clockwork garden: on the mechanistic reduction of living things

title: ClockworkGarden:OntheMechanisticReductionofLivingThings

author: Faber,RogerJ.publisher: UniversityofMassachusettsPress

isbn10|asin: 0870235214printisbn13: 9780870235214ebookisbn13: 9780585083445

language: English

subject Mechanism(Philosophy),Mindandbody,Quantumtheory,Teleology.

publicationdate: 1986lcc: BD553.F251986ebddc: 113/.8

subject: Mechanism(Philosophy),Mindandbody,

Quantumtheory,Teleology.

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ClockworkGardenOntheMechanisticReductionofLivingThings

RogerJ.Faber

THEUNIVERSITYOFMASSACHUSETTSPRESSAMHERST,1986

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Copyright©1986byTheUniversityofMassachusettsPress

Allrightsreserved

PrintedintheUnitedStatesofAmerica

SetinLinotronSabonbyG&STypesetters

PrintedbyCushing-MalloyandboundbyJohnDekker&Sons

LibraryofCongressCataloging-in-PublicationData

Faber,RogerJ.,1931Clockworkgarden.Bibliography:p.Includesindex.1.Mechanism(Philosophy)2.Mindandbody.3.Quantumtheory.4.Teleology.1.Title.BD553.F25 1986 113'.8 8528408ISBN0870235214(alk.paper)

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Tomyfather

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Contents

Preface ix

1WholesandParts:IntroductorySurvey

3

2TheCaseforMechanism

12

3ReductionandCommonSense

33

4Teleology:ReducingCybernetics

55

5Teleology:GoalsandAdaptations

76

6Teleology:Selectionism

99

7NonreductivePhysicalism

122

8MentalEventsinPrequantalAtomism

139

9PotentialityintheQuantumTheory

157

10MentalEventsinanIndefiniteWorld

184

11NotesforaQuantalWorldPicture

227

Bibliography 257

Index 263

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PrefaceInthisbookItrytodiscernthehumansignificanceofourcurrentscientificworldpicture,evaluatingcompetinginterpretationsandarguingfinallyforoneofthem.Nowargumentsdonotspringspontaneouslyoutoftheair;wedeveloptheminordertoorganizeourintuitions,theinformaldistillationofourexperiencesoftheworld.Nordoargumentscompletetheefforttounderstand;theyserveonlyinsofarastheyhelptomakesenseoffurtherexperiences,clarifyingandperhapscorrectingourintuitions.Experiencesareboththesourceandtheendofreasoning;wecannotrestuntilwehavebroughtintuitionandargumentationintoharmony.Itseemsappropriate,therefore,tointroducethisvolumeonthemechanistphilosophyofnaturebyrecountingoneofthesourcesofmyownintuitions.

Lookingforacolleague,aherpetologist,Ioncewanderedintoanunoccupiedresearchlaboratory,wherewhatseemedtobethepostmortemdissectionofaturtlestoodinastateoftemporarysuspension.Thebody,minusthelowershell,waspinnedonitsbacktoawoodenslab,itsinternalorgansexposed.Isoonsaw,however,thatthiswasnocorpse;thecreature'slegswereslowlytracingacrawlingmotionintheair.Theimageofthatdisturbingsightstayedwithme.Tocoolmyindignation,Itoldmyselfthat

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thebodyIhadseenwasonlyamechanismmadeofcells;thatnothingwasoccurringonthedissectingboardthatdifferedsignificantlyfromwhatgoesoninanautomobilerepairshop.TheturtlewithbeatingheartandwavinglimbswasinallrespectsexceptforthestufffromwhichitwasmadelikeaVolkswagenonarepairrackwithitsengineidlingandwheelsspinning.Wasittryingtoescape?No,notinthefullsenseof"trying."Notmoresothanaheat-seekingmissile,say,couldtrytohitatarget.Wasitfeelingpain?No;likeanymechanismitcouldnotfeel,itcouldonlyfunction.Thefiringofitspain-sensingneuronswasliketheglowingofalampthatwarnsaboutoilpressureoroverheatinginanautomobile.Ilearnedlaterthatthedissectionhadbegunwiththeroutineprecautionofseveringtheanimal'sspinalcordjustbelowthehead,sothepossibilityofpaindidnotarise.Thewarninglamphadbeendisconnected.Still,awiderquestionremained:Itisthecommonthreadrunningthroughthisvolume.Doesalivingorganismdifferfromafunctioningmachineonlyinbeingmadeofcarbohydratesratherthanhigh-carbonsteelandinhavingbeenformedbythespontaneousself-assemblyofmoleculesratherthanbydesigninafactory?Havingsomepersonalexperienceofwhatitisliketobealivingorganism,Ifeltinclinedtoanswerno.

Togivethatansweristomakeanantireductiveconjectureabouttheorganicworld.Findingsupportfortheconjectureisadauntingtask,notleastbecausethemechanisticviewoflivingthingsisfirmlyrootedinmodernevolutionarybiology.Nevertheless,theattempttocounter,oratleasttotemper,mechanisticreductionismappealstohumanistsofallideologicalstripes.SomeChristianshaveobjectedtoevolutionismbecauseitconflictswithaliteralinterpretationoftheBookofGenesis;someMarxistshaveobjectedtotheelevationofpartsoverwholesbecauseitdegradesthecollectiveinfavoroftheindividual.ButIsubmitthatthreatstothesespecialorthodoxiespaletoinsignificancecomparedwiththeinsultthatreductionismoffersto

ordinary,nondenominationalhumanism.Thatthreat,thedemeaningofthehumanperson,touchesreligiousandnonreligiousalike.

Havingexposedalittleoftheoriginofthisstudy,letmealsoalertthereadertothecharacterofitsdestination.Thisbookisofferedinsupportoftheantimechanistconjecture.Chapters1through7explorewhatcanbedonewithoutraisingtheancient

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riddleofmindandbody.InthemIlookforantireductiveargumentsthatwillstanduptotheseverestcriticismareductionisticmaterialistcouldlevelatthemwithoutchallengingthematerialist'sontology.Iconcludethatargumentsofthattypedonotdeliverwhatantireductionistsseek.Turning,then,tothemind-bodyquestion,Iargueinchapters8through11alongtwoindependentlinesforadeservedlyunpopularmetaphysicalposition,adualismofmindandmatter.

Doesadualistconjecturehangtogetherlogically?Doesitaccuratelyreflectthenatureofthings?Howweanswerthosequestionsdependsfinallyonwhetherornotwecanbringourbestargumentsandourtrustedintuitionsintoharmony.Pendingtheultimatejudgmentonthetruthofdualism,however,itisproperatthisstagetonotesomeofitsattractivefeaturesaswellasitsrepulsiveones.Bothkindsprovidereasonsfortakinganinterestintheconjecture.

Onthesinisterside,onemayfearthataddingmindstothefurnitureoftheuniversewouldcrackthedikeofReason,floodingtheintellectuallandscapewithmindreading,spoonbending,andfortunetelling.Ontheotherhand,onemightwelcomeadualisticframeworkinwhichwecouldhonormorewholeheartedlysomereasonableandhumanisticissues,suchastraditionalconcernswithaesthetics,ethics,andthedisciplinedmysticismsofWestandEast.Besides,dualism,forallitsinternalproblems,offersamoreinterestingprogram;itisamoreentertainingsourceofpuzzlesandspeculationsthanitsmonistalternatives.Canweaccommodatedualismwithoutsuccumbingtoblindunreason?Ithinkwecan.Iwanttourgethatweneednotdwellindesertlandscapesinordertopreservearationalsobriety.

Manypeoplehavehelpedtomovethisworkalongwithinspiration,criticism,andadvice.ForemostamongthemisAbnerShimony,whoguidedmeinmyfirstventureintoanewarea,whosuggesteddoinga

book,andwhosethoughtfulcriticismkeptitmoreorlessontrack.Manyothershavealsoreadandcommentedencouraginglyonvariousstagesofportionsofthemanuscript:especiallyWilliamC.Wimsatt,DonaldT.Campbell,ClaireMichaels,ForestHansen,LaurieShrage,RobertGlassman,PatriciaMcGoldrick,andRobertMannweiler.Theexpositionofquantummechanicsisconsiderablylessmuddled

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thanitmighthavebeen,becauseofthechallengingcriticismofDavidKavesh.IthankJulianaH.FederandCharlesA.Louchforshowingmesomeoftheoddnessandexcitementofmodernbiology.FormativestagesofseveralchapterswerereadattheCenterfortheInterdisciplinaryStudyofScienceandTechnologyofNorthwesternUniversity,tothefacultysack-lunchseminar,whoseabilitytosurvivetheemigrationofitsnucleus,DonaldT.Campbell,testifiestohowwellhefoundedit.ApaperreadtotheBostonColloquiumforthePhilosophyofSciencegrewintwodirections:moretechnically,intoanarticleinBostonStudiesinthePhilosophyofScience,vol.84,andlesstechnically,intochapters4,5,and6ofthiswork.IwishtothankM.PatriciaFaberformoralandpracticalsupportthatcarriedthewritingovermajorhurdles.ThanksareduealsotoLakeForestCollegeforitsfinancialsupport,andtoBostonUniversity,especiallytheDepartmentofPhysicsandtheDepartmentofPhilosophy,foritsstimulatinghospitalitywhileIwastakingsabbaticalleavefromLakeForest.Finally,IamgratefultoVirginiaCrist,whoseskillfultypingmadeprogresspossibleduringtheearlyandlatephasesofthisproject.

OneWholesandParts:IntroductorySurveyCommonwisdomabouttheworldguidesuswellindailyliving,butgettingalongpracticallyisnotenough;wealsowanttoweaveanaturalphilosophywithyarnspulledfromtheworkbasketofcommonsense.Thetaskischallenging,becauseourbeliefsandspeculationsaboutourselvesandourplaceinnaturemakeaknottysnarl,whosestrandspullincontrarydirections.InthisbookItrytodisentangletwostrongthreadsofopinionabouthumannaturewithoutcuttingeitherone.Iwanttopreservethetraditional,humanisticideathathumanbeingsactascausalandmoralunits;andIwanttodoequaljusticetothemodern,scientificstorythatweoperateascellularorbiochemicalmechanisms.Thehumanisticviewgrowsoutofordinaryhumanexperienceandhasbeenenshrinedinlawandintheworld'sreligions.Themechanistichasbeenassembledpiecebypieceasscientistsandothershavesoughttoworkouttheas-

sumptionsofrealism,materialism,andatomism;itfindsaninstitutionalhomeinWesternmedicine.

Atomism,thesourceofthelatterview,isaprogramforresearch,aprescriptionforhowtosetaboutthetaskofmakingsenseoftheworld.ThisprogramhaspersistedasanelementofWesternscienceandofWesterncommonsensefromthedaysofDemocritusandEpicurustotheageofWatsonandCrick.Thoughsomehavepronounceditterminallyill,atomismwillnotliedown.Norshouldit.Therevelationsproducedalmostdailybyresearchersinmolecularbiologyattesttothepresentvigorofthemechanistphilosophy.Rumblingsofdissatisfactionwiththeatomistprogrammayechodownthecorridorsofthephysicsbuilding,butinthegeneticslaboratorymechanisticreductionismlivessecureandbreatheswithnewvitality.

ADilemma

Despitethetriumphsalreadyachievedbytheatomistprogram,however,anditspromiseofstilldeeperinsightsintothemechanismoflife,therearereasonstofeeldistressedaboutmechanismasaphilosophy.Ifscientificknowledgeiscontinuouswithcommonsense,extendingandcorrectingtheknowledgeofthemarketplace,thenourmosttrustworthyinformationaboutthenatureofthingscomesfromourbestscientifictheories.Andtheyareatomistic.Atomismasaphilosophyofnaturecastsachillingshadowuponourimageofhumannature.Inthisgloomordinarythings,humanbeingsamongthem,acquireashadowyontologicalstatusbecause,accordingtotheatomistprogram,partsarespecifiablymorerealthanthewholestheycompose.ThefundamentalrealityisDemocritus's''atomsandvoid.''Thepatternsofarrangementandinteractionthatcharacterizetheobjectsofeverydayexperiencearemerelytheautomaticoutcomeoftheactivitiesoftheatoms.Thepatternshavenocausalefficacy;they

arenotimposeduponbrutematterbutarespunofffromthemindlessdanceoftheatoms.AccordingtoLucretius,

Slavery,riches,freedom,poverty,War,peace,andsoon,transitorythingsWhosecomingsandgoingsdonotaltersubstanceThese,andquiteproperly,wecallby-products.[LUCRETIUS,trans.HUMPHRIES,1968,p.33]

Inourordinarytalkabouttheworld,wehabituallyascribecausalagencytomacroscopicthingswhich,accordingtoatomistreductionism,areeitherconglomeratesofatomsorwhirlingpatternswhoseatomicmembershipscontinuallychange.Wenamethesethingsascausalagentsforconvenience,tosimplifythestorieswetell,oroutofignorance;buttruecausalagencyresidesintheparticlesalone.Accordingtoatomism,wearewhatouratomsdo.

Hereisadilemma.Ontheonehandweholdthatonecansaywhatsomethingreallyiswhatitisinitselfandapartfromtherelationsitsustainswithourselvesorotherthingsbylistingitsparts,tellinghowtheyarearrangedandmove,andmentioningthegenerallawsthatgoverntheirinteractions.InthisweechoarecurrentthemeofLucretius,whosethree-pointprogramofreductionlacksonlyareferencetogenerallaws:

...manythingshaveelementsincommon,Butdifferentlycombined......ItismostimportantBothwithwhatotherelementstheyarejoined,Inwhatpositionstheyareheldtogether,Andtheirreciprocalmovement.[P.43]

Ontheotherhand,wetakeahumanbeingtobetheverymodelbothofcausalagencyandofindividuality.Ournotionsofwhatitistobeaunifiedwholeandofwhatitistoactarebothderivedfromourexperienceashumanbeings.

Sometimesatomismiscriticizedonthegroundsthatitentailsadeterministicnegationofhumanwill.ButtheobjectiontomechanismraisedbyBrandBlanshard,himselfanavoweddeterminist,clearlyshowsthattheoffenseiscausednotbydeterminismpersebutbythepeculiarnatureofmechanisticdeterminism:

Whatmostaffronts[theplainman],Ithink,isthesuggestionthatheisonlyamachine,abigfoolishclockthatseemstoitselftobeactingfreelybutwhosemovementsarecontrolledcompletelybythewheelsandweightsinside.[BLANSHARD1958,p.10]

Blanshardgoesontoassertthatneitherhenortheplainmanfeelsaffrontedbyadeterminismthattreatsthethinking,willing

humanbeingasanindividualcausalagent,constrainedbythelogicalandaestheticnecessitiesinheringintheobjectsofhisthoughtandwill.IfIhavecorrectlypointedtothereasonformechanism'srepellentvisage,thenitiseasytoseebothwhyBlanshardcouldacceptaformofdeterminismwhilerejectingmechanismandwhyintroducingindeterminismintoanatomistphilosophywouldnotsoftenitsfeatures.Weobjectnottodeterminismassuchbuttothetransferralofcausalagencyfromhumanbeingstotheirparts.WhetherthosepartsmoveandcollideinstrictconformitytothelawsofaLaplaceanuniverseorswervefreelyasEpicurusandLucretiuswereforcedtoassumeor,indeed,whetherthosepartsexhibitquantumindeterminacy,theatomsretaintheirclaimtobetherealactorsonthestageoftheuniverse;whatevertheremaybeoffreedomornecessityintheworldremainsthefreedomornecessityoftheatoms.

Thedilemmaimplicitincommonsense(augmentedbyscience)issharpenedbythefactthatthegeneralprogramofreductionneednotalwaysproduceadehumanizedpictureofthings.Theworldseemstobesoconstructedthatthereductionofwholestopartscanbecarriedoutinstagestherearepartswithinparts.Atcertainstages,declaringtheinnerrealityofacompositeentitytobecomprisedinthearrangementandinteractionsofitspartsmayleadtoamore,notless,humaneunderstandingofthesystem.Considerforexamplethetensionbetweenourupper-leveldiscourseaboutstateandsocietyandourlower-leveltalkaboutindividualpersons.JeanJacquesRousseau,whofavorsholismhere,criticizesthosewhoconsider"themoralpersonwhichconstitutestheStateasacreatureoftheimagination,becauseitisnotaman"(Rousseau1791,1947,p.18).Rousseau'sdescriptionofdemocracyfurtherillustrateshisholism:

Butwhenthewholepeopledeterminesforthewholepeople,itconsidersonlyitself;andifarelationisthenformeditisonlyarelationofthewholeobjectfromonepointofviewtothewholeobjectfromanotherpointof

view,andthewholeitselfisnotdivided.[P.33]

IncontrasttoRousseau'sfavoringoftheupperlevel,JohnStuartMill(1859,1975)takeshisstandagainstthecontrolofindividualsbythestatesimplybyrefusingtotreatthecompositeentityasaunit:

Itisnowperceivedthatsuchphrasesas"self-government"and"thepowerofthepeopleoverthemselves,"donotexpressthetruestateofthecase.The''people"whoexercisethepowerarenotalwaysthesamepeoplewiththoseoverwhomitisexercised;andthe"self-government"spokenofisnotthegovernmentofeachbyhimself,butofeachbyalltherest.[P.5]

ThehumaneeffectofMill'sresolutereductionismisnotlostinthisageofgeneticengineering:WeneedtoberemindedthatloftytalkaboutMancontrollinghisownevolutionarydestinytranslatesintotheplainandancientfactofsomemencontrollingothers.Butaprinciple,onceadopted,mustbeappliedconsistently.Anditseemsthattheconsistentapplicationofatomismmustcarryusdownthroughtheworld'slevelsoforganizationuntilweacknowledgethatthefulltruthaboutanythingwhateverresidesinstoriesabouttheparticlesofphysics.

PopularRemedies

CantheconflictbetweenthereductionistandholiststrandsofcommonsensebeassharpandintractableasIhavesuggested?Onlyaclosescrutinyofcarefullyconstructedargumentsandcounterargumentswillleadtoasatisfactoryanswertothatquestion.Butbeforeundertakingsuchastudy,andtomakethelaborseemworthwhile,letmebrieflyconsiderandbrieflydisposeoffivesimple,yetpopularattemptstoescapethereductionisthornofthedilemma.

1.Awhole,anywhole,ismorethanamerecollectionofparts.Thisreplyiscertainlytrue,butitmisrepresentstheatomistprogram;hence,itisnotareplytoreductionism.Asnotedabove,Lucretiusrecommendsathree-partprogram:Theatomistsetsforththetruenatureofanycompositeentity,notonlybylistingitspartsbutalsobyspecifyingtheirrelativepositionsandtheirmotions.Tothisprescriptionamodernatomistwouldaddareferencetothelaw-

governedinteractionsamongtheparts.Sothefirstreplyfailsbyunderestimatingtheresourcesoftheatomistprogram.Thenatureofacompositethingmaynotbeconveyedbyasimpleenumerationofitsparts,butwecancapturethewholedynamicalactivityinacompletedescriptionofwhatthepartsaredoing.

2.Noonewilleverbeabletoturnthescienceofhumanbehaviorintoabranchofappliedphysics.Thisreplyisalsocorrectinwhatitstatesbutmisrepresentsthequestion.Noteventhemostenthusiasticreductionistthinksthatupper-levelsciencessuchasbiologyandpsychologywillinfactbereplacedbyappliedphysics.Anyattempttoexplainanypartofthenaturalworldmuststrikeabalancebetweenthecompetingclaimsofutilityandliteraltruth.Forallsortsofreasons,theneedforbrevityperhapstheleastofthem,sciencesthattreatcompositeentitiesasunitswillalwaysbenecessaryinpractice.Thequestioniswhethertheyarenecessaryinprinciple.Sothesecondreplyfailsbyansweringanirrelevantquestion.

3.Thepropertiesofwatercannotbeexplainedbythepropertiesofhydrogenandoxygen.Thisreplyisasampleofaclassofrepliesassertingthatupperlevelsoforganizationdisplayirreducible,emergentproperties.Idonotknowhowtomakeageneralcriticismofthewholeclass,andIintendtoconsidersomemorechallengingexamplesofsupposedemergentpropertiesinsubsequentchapters.Butthisparticularreplyiseasilymet.Ofcoursethepropertiesofwaterinbulkcannotbeunderstoodintermsofthebulkpropertiesofhydrogenandoxygen.Themacroscopicsubstancewaterisnotmadeupofthetwosubstanceshydrogenandoxygen;itiscomposedofwatermolecules.And,althoughchemistsstillwritetheformulaforamoleculeofwaterasH2O,nochemistactuallythinksofthemoleculeasthuscomposed.Rather,asinglemoleculeispicturedasmadeupoftwoprotons,anoxygennucleus,andeighteenelectrons,interactingdynamicallybymeansoftheelectromagneticforceandaccordingtothelawsofquantummechanics.Theatomistmustbesuretoidentifycorrectlytheconstituentsofthecompositeentitieshestudies;therecentsuccessesofabinitioquantum-mechanicalcalculationsofthepropertiesoffairlycomplexmoleculesshowthatmodernchemistryhasmadetherightidentification.Thepropertiesofwatercanbe

explainedbyreferencetotheproperties(includingtheinteractivepropensities)ofneutrons,protons,andelectrons.Sothisattempttoestablishanirreduciblepropertyfailsbyincorrectlyidentifyingtheconstituentsoftheupper-levelentity.

4.Thecomponentsofasystemcannotbeunderstoodapartfromtheirmembershipinthewhole.Thisreplypointsout,quite

rightly,thattounderstandwhatonecellofalivingorganismisdoingwemuststudynotjustthepropertiesoftheisolatedcellbutalsohowthecellinteractswithothers.Andtounderstandahumanbeingwemustnotehowthepersonisaffectedby,andinturnaffects,othermembersofsociety.Anecologicalattitudetowardnatureemphasizestheinterrelatednessofthingsthebalanceofopposingforcesintheequilibriumbetweenpredatorandprey,andthecooperationamongotherlivingthingsformutualbenefit.Butinteractiondoesnoterasedistinctions.Thingsthatinfluenceoneanothercausallystillretaintheirindividuality.AtomicparticleAwouldbedoingsomethingelsetodayhaditnotcollidedwithByesterday,butevenwithoutthatencounterAwouldstillexistandwouldstillhavethesamemassandchargewouldhavethem,indeed,evenifBhadneverexisted.Causalinterdependencedoesnotentailontologicaldependence,stilllesstheundifferentiatedwholenessadvocatedbysomeWesterninterpretersofEasternthought.Theatomists'worldcontainsdistinct,individualparticles,buttheatomsdointeract.Pointingoutthatthepiecesarenotisolatedmerelybrushesasideastrawopponent.Thisreplyshowsthatanyadequateaccountofacompositeentitymustencompassasufficientlylargesetofparts;apictureofanisolatedpartisnotapictureofasystemofinteractingparts,andahistoryofanisolatedpartisnotahistoryofthepartasitisacteduponbyothers.But,asIshallargueinmoredetailinchapter2,itisessentialtodistinguishanappealforadequatescopeatthelowerlevelfromanargumentfortheirreplaceabilityinprincipleofupper-levellanguage.Thefourthreplyestablishestheneedforscopebutfailstoblockthemovefromuppertolowerlevel.

5.Realityhasnostructureofitsown.Accordingtothisreply,suchstructureastheworldseemstodisplayisimposeduponitbythearbitrarylinguisticandconceptualcategoriesweemployinourdescriptions.Thusthepartitionoftheworldintoatomsrecommends

itselfwithnogreaterforcethandoalternativepartitionsthatpresentotherthingshumanbeings,forinstanceasthecausalagents.Tosatisfyourdescriptivepurposes,wearefreetochooseanyoftheseapparentlyrivalwaysofdividingupreality.ThiscriticismofatomismwasraisedbyLudwigWittgenstein(1958),givenameasureofscientificstandingbyBenjaminWhorf(1956),andpopularizedbyCarlosCasteneda(1974).

Butthecriticismignoresthefactthatwecannotfreelyadoptjustanysetofdescriptivecategories.Mostofourattemptstoformulatetheorganizationalpatternsoftheworldraiseexpectationsthatsubsequentexperiencedashestopieces.Inthiswaytheworlditselfdisposesofallbutatinyfractionofthetheoriesweproposeinourattemptstounderstandit(Campbell1960;1974a).Thescientificenterprisesucceedsonlybecauseitmeeklyapproachestheworldonitsownterms,withoutinsistingonpreconceivedconceptualschemes.

Sweepingasidetheseweakormisdirectedattacksonreductionismmerelyclearsthewayforthemaineffort.Manymorecarefullyconstructedargumentsremain,argumentsthatpromisetorefute,oratleasttomitigate,themechanisticpictureIhavesketched.Ofonemajorclassofreplies,however,Ishallhavenothingtosayuntiltheclosingchapters,namely,thosebasedonadualistontology,suchasthemind-braininteractionismofPopperandEccles(1977).Ishallconsideratfirstonlyrepliesthatare,ifnotexplicitlymaterialist,atleastcompatiblewithamaterialistontology.Suchrepliesappealbecauseoftheireconomy:Iftheywork,theirsuccessisthemoreimpressivefortheirhavingdrawnuponaminimaltheoreticalarsenal.If,evenwithinamaterialistphilosophy,mechanismcouldbesoftenedorrefuted,thentherefutationwouldbesecureindeed.

Summary

LetmesummarizethisintroductionbystatingmycentralquestioninaformthatshowshowIintendtoapproachthisassessmentofthemechanistworldpicture.

IwishtoaskwhatWillardQuine(1960)identifiesasthecentralquestionofontology:Whatisthere?And,althoughIshallbesatisfiedwithalessformalcriterionthanhis,IshallfollowQuineinlookingtoourcurrentscientificworldpictureforatleastpartoftheanswer.

Whatweacknowledgeasreal,our"ontologicalcommitment,"isrevealed,hesays,inourlogicallyformalizedscientifictheories:thetermsoverwhichthequantifiersofthetheoriesrangerepresenttheitemsthatpopulatetheuniverse.Alessformaltestofonticcommitmentwillsufficeformypurposes.Thepictureoftheworldthatwegetfromscienceandfromcommonsensehighlightsamultitudeofactivities:thegrav-

itationaltuggingthatdivertsJupiterintoitsellipticalorbit;thepressingofaquantityofheliumgasagainstthewallsofaneopreneblimp;thesurvivingintolatergenerations,throughnaturalselection,ofcertainallelesinsteadofotherslessfavored;therespondingofpersons'mentalstatestothephasesofthemoon,andsoon.What,infact,isbeingdoneoutthere?Isnaturalselectiontrulyanactivityperformedbysomeagent?Doesaperson'smentalstatereallydependonwherethemoonisinrelationtothesun?

Havingsettledsuchquestionsaswellaswecan,wenextinquire,foreachactivity:Whatisdoingit?Herewestriveforparsimony:Ourtaskmustbetowinnowthelistofactors.Thisparingdown,theprincipaltaskofreductionism,producesanincreaseinunderstanding.Thegaspressesontheinnerwallsofitscontainer;butthemoleculesofwhichthegasiscomposedcollidewiththemoleculesthatcomposethewalls.Shouldweretainbothactivitiesonourlist?No,answersreductionisticscience,thepressingdonebythegasisnothingoverandabovethecollidingdonebythemolecules.Theactivityofthewholeisbuiltupoutoftheaggregatedactivitiesofitsparts.Whattheydoincludes,byaggregation,whatthegasdoes;andtheydomuchmorebesides.Therefore,thegreatdramaoftheuniverseisnotplayedoutbybothgasesandmolecules;onlythemoleculesneedtobefeaturedonthemarquee.Throughoutthisinvestigation,then,Ishallfocusuponactivities,assumingthroughoutthateveryrealactivityisdonebysomereal,individualdoerorsetofdoers.Theseagentsaretheinhabitantsoftheuniverse.Atomisticsciencehastakenupthechallengeoftryingtounderstandeveryactivityasbuiltupbythebustlingofmaterialparticles.Iwanttoaskwhetherwecanfindanyactivitiesthatcannotbesounderstood.

TwoTheCaseforMechanismAtomismis,ofcourse,merelyastrategyorprescriptiveprogramforresearch,butitssuccesseshavemadeitvirtuallysynonymouswiththecontentofmodernscience.Althoughphilosophersofsciencehaveundertakenquiteproperlytoproducegeneralanalysesofcausalexplanation,inthepracticeofsciencewearenotsatisfiedwithanexplanationthatfailstoestablishtheconnectionbetweencauseandeffect;and"connection"heremeans"mechanism."Theassociationsandcorrelationsreportedbymedicalresearchersandsociologists(e.g.,thestatisticalassociationofsmokingwithvariousdiseases)areregardedasmereindicationsofunderlyingmechanisms.Whenweclaimthatacorrelationdiscoveredinasystemismorethanacoincidence,weimplythatsomepatternofinteractionsamongthepartsofthesystemliesoutthere,waitingtobediscovered.

Threefeaturescharacterizeatomictheory:separability,context-independence,andlocality.Thepartsmustbeseparablefromthewholestheycompose,notjustconceptuallybutphysi-

callyaswell.Theymustbecapableofindependentexistence.1Second,thepartsmustcarrytheirpropertiesunchangedfromonecomplexsituationtoanother.Theintrinsicpropertiesandmodesofinteractionthatdistinguishthevarioustypesofparticlebelongtothemabsolutelytheydonotdependuponthedegreeofcomplexityortheorganizationalpatternsofthelargersystem.Inpracticethismeansthatthepartscanbecharacterizedbythepropertiestheyrevealinsimpleexperimentalcontextsandthatthesepropertiesaccountforallthatgoesoninmorecomplicatedcontexts.Consequently,thedirectionoftheoreticalexplanationmustrunexclusivelyfromthepartstothewhole.Nowthisexplanatoryasymmetrybetweentheoriesaboutpartsandtheoriesaboutwholesreflectsitsontologicalcounterpart:Thewholesdonotexistintheirownrightbutdependupontheexistenceoftheirparts.Whenwelistthepartsandtellhowtheyarearrangedandinteract,wemakeitclearwhatthewholereallyis.

Third,withthesingleandperplexingexceptionofquantummechanics(Bell1965;Clauseretal.1969),allatomistictheoriesexhibitwhathasbeencalledlocality;thatis,theypresenteachparticleasbeingaffectedbyandasactingupononlytheobjects(includingtheparticlesthatmediateforcefields)initsimmediatespatiotemporalneighborhood.Interactionsremainlocalatalllevelsofdescription.Cells,forinstance,behaveinaccordancewiththeirowninternalstructureandinresponsetothecausalinfluenceimpingingupontheiroutermembranes.Theyarenotdirectlyaffectedbyanyotherobjectsorbyanyglobalpropertyofthesysteminwhichtheyparticipate.

Levels:SomeDistinctions

Curiously,amerelyincidentalfeatureofatomistreductionismhasbeenresponsibleforitssuccess.Atomismprobablywouldhavediedinitsinfancyhadtheworldnotbeensoconstructedthatthereductiveanalysisofwholesintopartscouldproceedbystages.Socialsystems

arecomposedofindividualorganisms,organismsaresystemsoforgans,organsaremadeupofcells,cellsofmolecules,moleculesofnucleiandelectrons,andsoon.For

1/Oneversionofthetheoryofquarksviolatesthisrule(Drell1978).

thatreason,wemaytalkabouttheworldconvenientlyatanyofseverallevels.Nevertheless,accordingtothereductionistprogram,thelowerleveloftwoaccountsofthesamesystemapproximatesmorenearlytothewaythingsare.Eventhoughwedonotyethaveanassuredlyfundamentalinventoryofultimateparticles,wemayeffectareductionfromonelevelofdiscoursetothenextbelowitconfidentthatastephasbeentakeninthedirectionwherethecompletetruthlies.

Inanydiscussionconcerningthereductionoftheoriesonagivenleveltotheoriesonalowerlevel,itisessentialtobeclearastowhichlevelagivensampleofdiscourseresideson.Usagevarieswidelyintheliteratureonlevelsofdescriptionandlevelsoforganization.AsIshallusetheterm''level,"thedistinctionbetweenpartsandwholeswillalwaysdecidetheissue.Languagethattreatsacompositeentityasaunit,avoidinganyimplicationastoitsbeingcomposedofparts,functionsontheupperlevelofthatpart-wholeinterface.Andastorythat,indirectlyorbyimplication,assignscausalrolesandotheractivitiestothepartsfunctionsonthelowerlevel.

Onemustnotconfuseanincreaseintherangeorscopeofanarrativewithashifttoahigherlevel.Letmeillustratethispointwithsomeexamples.

1.Whenaphysiciststopstalkingaboutthepropertiesofindividualatomsofheliumandstartstalkingaboutthedoingsofaswarmofatomsandoftheinteractionsamongthem,therangeoftheconversationhasbeenbroadened,butitslevelremainsthesame,fortheobjectsreferredtoarestillatomsofhelium.Onlywhenthephysicistleavesoffspeakingofatomsaltogetheranddescribesinsteadthebulkproperties,suchasthecompressibility,ofheliumgasortheinteractionofasampleofheliumgaswithotherobjects(e.g.,thepressureexertedbythegasonitscontainer)doesthediscoursereacha

higherlevel,foronlythenarethegasandthecontainertreatedasunitswithoutregardtotheirbeingmadeupofatoms.

2.Whenasociologistwarnsapsychologistthattheactionsofanindividualhumanbeingcannotbeunderstoodwithoutreferencetotheinfluenceuponthatpersonofmanyotherpeople,thesociologistisnotshiftingthediscoursetoahigherlevelbutmerelyextendingtherangeoftheconversationtoincludemoreindividualsatthesamelevel.Ahigherlevelisreachedonlywhen

thesociologistbeginstospeakofsocialgroupsandtheinteractionsamongtheminsuchawaythatthegroupsaretreatedasunitswithoutreferencetotheirbeingcomposedofindividualhumanbeings.

3.Considerajigsawpuzzle.Wemaysayofthepuzzlethatithasamassoffiftygrams.Noneofitspartshasamassoffiftygrams,sothepredicateattachestothewholepuzzle.Moreover,wehaveneithersaidnorimpliedthatitconsistsofparts.Consequently,toestimatethemassofajigsawpuzzleistoengageinupper-leveltalk.Butwemayalsosayofthepuzzlethatitconsistsof750interlockingpieces.Thatpredicate,too,attachestothewholepuzzle.However,theassertionthatthepuzzlehas750piecesisnotutteredattheupperlevel,becauseitreferstotheentityasasystemofparts.Notethatanupper-levelassertionaboutanentireentityneednotimplythatitisnotcomposite;toqualifyasupper-leveldiscoursethedescriptionmustmerelybefreeofimplicationsabouttheexistenceofparts.

4.Theconceptoftemperatureattachesonlytowholesystemsofmoleculesandnottoindividualones,butthehistoryoftheconceptshowsatransformationfromtheuppertothelowerlevel.Whentemperaturewasdefinedmerelyasthepropensityofanobjecttoexchangeheatwithothers,nothingwasimpliedaboutthemolecularcompositionofthebodiesinvolvedintheexchange;thus,theoriginaldefinitionoftemperaturewaspartofupper-leveldiscourse.Butinmodernsciencetemperaturehascometobedefinedasastatisticalpropertyofthedistributionofenergyamongthepartsofanobject,whichdistributionaccountsforthepropensity.Sothecurrentdefinitionoftemperaturereferstotheobject'sbeingmadeupofparts.Temperature,thoughitattachestothewholesystem,isnowalower-levelproperty.

5.Whenwemakeafunctionalanalysisofamechanism,weoftendesignateasubassemblyintermsofitsfunctionwithinthelarger

mechanism.Suchadescriptionmoveswithinthelevelofthemechanism'spartsbutnotthestilllowerlevelofthepartsofthesubassembly,fortheirpresenceisnotimplied.However,althoughbeingafeedbacksystemisapropertyofanentiremechanism,itisalower-levelproperty.AsIshallargueinchapter4,whenwecallsomethingafeedbacksystemweimplythatitspartsarearrangedandcausallyactuponeachotherinacertainspeci-

fiedway.Byimplyingthatthesystemhasparts,weplacetheconversationattheirlevel.Talkaboutfeedback,thoughaboutwholesystems,islower-leveltalk.

Aretheentitiesnamedatvariouslevelsallonanequalontologicalfooting?Aresocieties,organisms,cells,molecules,andsubatomicparticlesequallyreal?Theassumptionthattheyarewouldestablishanuneasytruceamongtheacademicdisciplinesassociatedwiththeselevels.Nevertheless,iftheprogramofreductionhasmerit,suchalaminarrelativismwillnotdo.Accordingtotheprogram,thedescriptions,includingthecausallaws,appropriatetoanyupperlevelpresentalessfaithfulpictureoftheworldthanthedescriptionspropertolowerlevels;thus,theentitiesnamedinupper-leveltheoriesmustforfeitanyclaimtobelistedasagentsintheworld'saffairs.

Butprogramsandpromisesarenotenough.Aboutaprogramasancientasatomismitisentirelyappropriatetoaskwhethertheprogramfitsthenatureofthings,whetherthepromisescanbemadegood.Weneedanargumentinsupportoftheatomistreductionprogramfortworeasons:First,weneedtoknowwhethertotakethereductionistclaimsseriously.Second,becauseweshallshortlyturntotheconsiderationofanassortmentofantireductionisticclaims,weshallrequireanopposingargumentagainstwhichtheymaybetested.Putintodirectconfrontationwithastrongargumentforreductionism,theantireductionisticargumentswillbeabletoshowtheirstrength.Canreductionismbeexpectedtowork?Letusconstructanargumentontheaffirmativesideofthisquestion.

EliminativeAtomism:ATargetArgument

Ourlinguisticfreedomtomoveatwillfromonelevelofdescriptiontoanotherexposesustoalogicaltrap.Weareoftentemptedtointroduceintoanarrativetoldatonelevelanagentwhosenativecountryliesat

ahigherorloweraltitude.Rousseau,scrupulousinthisrespect,warnsagainstmixingthelevelofdescriptionatwhichastatemayfunctionasaunitofthenarrativewiththelevelatwhichpersonsformtheunits:"Infine,StatescanonlyhaveotherStates,andnotmen,forenemies,becausetherecanbenotruerelationbetweenthingsofdifferentnatures"(1791,1947,

p.11).TheblunderRousseaushunsexemplifieswhatGilbertRylehastermedthecategorymistake(Ryle1949,p.16).InwhatfollowsIshallarguethatanyattempttoproduceacompletedescriptionoftheworldatalevelhigherthanthemostbasiconewilldisplaymysteriouscausalgapsthatcanbefilledonlybyconscriptingentitiespropertoalowerlevel,therebyillicitlyrelating''thingsofdifferentnatures."Intheinterestsbothofcompletenessandoflogicalcoherence,then,weareforcedtoabandoneachupper-levelnarrativeinfavorofalowerlevel.

Toillustratethecategorymistake,Ryletellsastoryaboutavisitortoauniversitywho,afteratourofthebuildings,gardens,andplayingfields,askstobeshowntheuniversity.NowRyle'snaivesightseermadearathermoreinterestingerrorthanthekindIwishtofocuson,forauniversityismorethanjustthebuildingsandotherlandmarksconsideredasapatternedwhole;itisalsoanetworkofhumanconventions,intentions,andobligations.Butlessinterestingmistakesmayalsobeinstructive.Supposethatthesameobligingtouristcouldbeinducedtodisplayhissimplicityinapoultryyard.Afterbeingintroducedtoeachindividualchicken,heaskstobeshowntheflock.That,too,thoughmoreelementarythanhisfauxpasinacademe,isindeedablunder.Anarrativeaboutanindividualhen,orevenaboutseveralhensasindividuals,occursonthehen'slevel,butmentioningaflockraisesthestorytoanotherandhigherplane.Thesuggestionthatonehenattackedanotherorevenseveralothers,framedasitisconsistentlyatthelowerlevel,isacoherentsuggestion;equallycoherentistheupper-levelassertionthatoneflockattackedanotherflock(thoughonewouldhardlylookforsuchorganizedbelligerenceinpoultry).Buttosuggestthatanindividualheninteractedinanywaywithaflockistolapseintoincoherence.Thoughourtalkabouttheworldmaybeframedatmanydifferentlevels,weoughttomaintainthepurityofourlayers;ifwemixthemupwebreednonsense.Hens

interactwithotherhens,notwithflocks.Aheniscapableofmanythings,includingpeckinganotherhen;buteventhemostaccomplishedofchickenscannotpeckaflock.Mixinglevelsinourdescriptionsoftheworldsimplyconfusesthem.ToadaptoneofRyle'saphorisms,thewordsforhensandflockscannotbeputtoroostinthesamelogicaltree.

IncoherenceofUpper-LevelDescriptions

Ifourlinguisticpracticesreflectthenatureofthings,surelytheycanbepursuedwithoutthreatofinevitableincoherence.Descriptivemodesthatproduceincoherence,evenifonlyoccasionally,mustberegardedwithsuspicion;howeverusefultheymaybe,thetruthisnotinthem.Butwefindinpracticethattheworldissoconstitutedthatourtalkingofflocksandotherupper-levelentities,ifpracticedwithoutrestraint,inevitablyleadstoincoherence.Thoughwemaysetouttodescribetheworldconsistentlyatacertainupperleveloforganization,wewillencountereventsinvolvingtheupper-levelentitieswhichoccurinsuchawaythat,tospeakofthematall,wemustdropourdescriptiontoalowerplane.Thelinguisticstrata,sotheworldisconstituted,arenotwatertight.Letmecitetwoexamplestosupportthisclaimonefictitiousandonebasedonreportsofspacetravelers.

Supposethefollowingdramaunfoldsinsomepoultryyard(Igivefirstalower-levelaccount):Theassortedbiddiesareindustriouslyscratchingamongthepebblesandseedswhenamaraudingfoxincautiouslyshowsitsfaceinsomenearbybushes.Oneofthehenshappenstonoticetheenemyandrunsforcover,squawkingagitatedly.Theothersdonotseethefox,buttheyknowconsternationwhentheyhearit,sotheyallfollowthefirsthen.Next,considerhowanupper-levelaccountofthesameincidentwouldrun:Theflock,wemightsay,relocatesitselffromtheopenyardtotheshelterofthehencoop.Attheupperlevelthestorycondensestoamereheadline.Buthowdocausalinfluencesfareatthislevel?Whatcausedthatunit,theflock,tomove?Thefoxdid,certainly(andherewealreadyfeeluneasy,forisalonefoxonthesamelogicalplaneasasocialentitylikeaflock?),buthowdidthefoxcausethatevent?Bywhatmechanismormodeofinteraction?Well,italloweditselftobeseenbyahen;sowemightbe

temptedtosaythattheproximatecauseoftheflock'sremovaltoshelterwastheactionofthatalerthen.Butnotehowthatsentencemixeslogicalcategories.Itcanbesavedfromincoherenceonlybysubstitutingfortheterm"flock"areferencetoalltheindividualsthatcomposeit.Ifachickencannotpeckaflockbutcanonlypeckotherchickens,italsocannotputaflocktoflight.Soitturnsoutthat,althoughitmaysuitourconvenienceasnarratorstospeakofflocksandtheirhistories,the

worldwillnotcountenanceourdoingsoconsistently.Flocks,wediscover,getthemselvesintotroublefromwhichonlyhenscanrescuethem.Likewise,ourupper-leveldiscourseleadsusnarratorsintodifficultiesfromwhichweescapeonlybyabandoningtheupperlevel.And,havingrelocatedtothelowerlevel,weencounternoneedtoriseagain,exceptforthesakeofemployingaconvenientshorthand.Henceforth,upper-levelthings,thoughnamedasunits,areconceivedofascollections.

Mysecondexamplewaswidelyreportedwhenastronautswerefirstspendingextendedperiodsinorbitbeyondtheprotectiveinfluenceoftheearth'smagneticfield.Severalofthesespacetravelersreportedexperiencingthesensationofirregularflashesoflightwhilerestingindarknesswithclosedeyes.Theexplanationproposedforthisphenomenonwasthatthelightsensationswerecausedbymassiveandhighlyenergeticcosmic-rayparticlesstrikingindividualphotoreceptorcellsintheretinasoftheastronauts.Thishypothesiswascorroboratedwhensomeintrepidterrestrialexperimentersplacedtheirownheadsinthebeamsofparticleaccelerators(McNulty,Pease,andBond1978).Therefore,wemightgliblyandincautiouslysay,theastronautsdetectedcosmicrays.Avisualexperience,aneventinvolvingahumanbeing,wascausedbywell,wewouldliketosayanucleusofiron-57.But,asRylehascautionedus,personsandatomicnucleidonotcontendforseatsonthesamelogicalbench.Personsinteractwith(amongotherthings)otherpersons,andnucleiwithothertinychargedparticles.How,then,arewetodescribetheeventinwhichthepersonandthenucleusparticipated?Notbyclingingtotheupperlevel,fortherenucleiarenotpermittedtofunction.Onthatleveltheperceptualeventhasnocause.Sowemustrelinquishourreferencetopersonsanddescendtothelevelofatoms;onthisdescriptivelevelthestoryunfoldsinitscompleteness,withoutasuddenreticenceimposedbylogicalscruples.

Itwouldbeeasytomultiplymoreprosaicexamplesofthistype.Cosmicraysareknowntoproducethefamiliarvaportrailsincloudchambersandarethoughttotriggerlightningflashes.AsingleXrayphotonmaycauseamutanteyecolorinastrainoffruitflies;and,torevertoncemoretohigherlevels,theactionofasinglepersonmayleadtotheoverthrowofastate.

Whatcanwesay,then,aboutourhabitsofspeakingabout

upper-levelentities,includingpersons,asunits?Only,itseems,thatwemaycontinuetodosowithinlimitsandforthesakeofconvenience,recognizingthattheworldissoconstitutedthatsuchtalkmustsimplybedroppedintheinterestsofaccuracywhentheoccasiondemands.Butperhapsnotmerelydropped.BecauseincidentsofthesortIoutlinedforthepoultryyardhavebeenfamiliarpartsofeverydaylifesincebeforetheEnglishlanguagewasformed,wehaveastandardlinguisticdevicefordealingwiththem:Wetreattheterm"flock"asacollectivenoun,toshowthat,thoughaflockmaybeaunityinourspeech,itisapluralityinitself.Wehavenotalwaysregardedhumanbeingsaspluralities,butrecognitionofthefactis,nevertheless,ofgreaterantiquitythanthespaceprogram.Theelderlybonvivantwhoinformsusthatthesluggishnessofhisliverisresponsibleforhisattendanceatamineralspringsresortmayhavestoppedmixinghisdrinksbutnothislevelsofdescription.Languageistherepositoryofourknowledgeabouttheworld;eventhestructureoflanguagereflectstosomedegreethatknowledge.Butstructurechangesmoreslowlythanknowledgegrows.Flockisacollectivenounbecausewehavealwaysknownthataflockisacollectionof,forexample,hens.Ironbarisnotacollectivenounnotbecauseabarofironisaradicallydifferentsortofentitybutbecausewehavebutlatelylearnedthatabarofironisanarrangementofironatoms.

Atwhateverlevelofdescriptionourtalkabouttheworldmaybeset,itcouldnotpretendtobecompleteunlessitincludedsomereferencetocausalinteractionsamongtheentitiesthatbelongtothatlevel.Thecausalinfluenceofonethingonanotheris,atanylevel,whatmakesournarrativehangtogether.Yetwefind,wheneverwelookcloselyatcausalactions,thattheflowofupper-levelnarrative,whenfollowedfarenough,alwaysvanishesintothesands,onlytoberecovered,freshandbroaderthanbefore,asasubterraneanstream.Whenwecharacterizethingsandeventsatanupperlevel,whatmaybethe

natureoftheconnectionsbetweenthemisultimatelymysteriousuntilwedescendtolowerstrata;butwhenwedescendwealwaysfindthatthemysterybeginstoclarify.Theconnections,aboutwhichwewereunabletospeakcoherentlyattheupperlevel,areseentobeinteractionsamongthepartsthatcomposetheupper-levelentities.Allthisisnottosaythattheultimateresultofoureffortstolookinto

causalconnectionsisthedispellingofallmystery;thecausalinteractionsamongtheultimateatoms(ifweeverfindthem)cannotthemselvesbeexplicatedintermsofstilllower-levelmechanisms,preciselybecausetheyaretheultimateparticles.Butsurelyweoughtnottomultiplymysteriesbeyondnecessity.Howquarksandgluonsinteractmayturnouttobejustbrutefactandhenceanultimatecausalmystery;buttheinfluenceoffoxesuponflocksisnotmysteriousifwearewillingtotalkofhens,noristhehereditaryinfluenceofparentsupontheiroffspringmysterioustoonewhoacknowledgestheexistenceofmoleculesofDNA.Forthesereasons,anintegralpartofthereductionistprogramistheclaimthatallcausationmustultimatelybeunderstoodasphysicalcausation.

Whenflocksinteractwithhensandpersonsinteractwithatomicnuclei,theonlycoherentlevelofdescriptionisthatofthelowerlevel:Flocksmustberegardedaspluralitiesofhensandhumanbeingsaspluralitiesofsubatomicparticles.Thecausallawsweemployinupper-leveldiscourseareeitherhelplesslymuteatinconvenientpointsor,ifweintroducelower-levelentitiestopatchupthegapsintheupper-levelnarrative,crazilyincoherent.Upper-leveldescriptionsmaybeconvenient,economical,practical,andevocative,buttheyarenotfaithfultothewaythingsare.Havingrecognizedthesefacts,wehavebeenforcedtoalterourunderstandingofupper-levelthingsforever.Wearecompelledtoadmitthatanyupper-levelentity,beitaflockofhensorahumanbeing,farfromactingasacausalagentinitsownright,ismoreaccuratelydescribedasacollectionoflower-levelentitiesarrangedinsomefashionandinteractingaccordingtotheirowncausallaws.

Soourordinary,causal,explanatorytalkaboutmacroscopicobjectsiseithersuperficialtothepointoferrororsuperfluoussuperficial,infact,erroneous,ifitistakenasidentifyingtheactualcausalagents;superfluousinthatthemicroscopicaccountdoesnotneedtobe

supplemented,forinmentioningalltheinteractionsitlistsbothallthecausalagentsandtheirrelevantproperties.Itissuperfluousalsobecause,ifanupper-levelentitysimplyisitspartsarrangedandinteractingassuchpartsdo,thenupper-levellawsareobtainablebymeansofacombinationofapproximation,hypostatization,andinference,accordingtotheusualstandardsofwhatphysicistscallderivation.

InsubstantialityofUpper-LevelThings

Thingsatanylevelendure.Thatispartlywhywedesignatethemasentities.Ishallarguethatthemanneroftheirenduringprovidesanadditionalreasonfordenigratingtherealityofsomeupper-levelthings,amongthemlivingorganisms,whoserealitywemoststronglywishtouphold.Considerthefollowingexamples.

Intheworldasreconstructedfromanatomistontologywefindcollectivesofquitedifferentsorts,allofwhicharetreatedalikeinordinaryspeechbutdifferintherelationofparttowhole.Ononeextremewefindenduringsetsofatoms,suchasbilliardballsandrocks,whoseatomicmembershipremainsfixedornearlyso.Ontheotherextremewefindourselvesapplyingnamestocollectionswhosemembershipsarecontinuallychangingandtreatingthesecollections,linguisticallyatleast,justaswetreatrocks.Inthiswaywemayassertthatthetrafficonanexpresswaywasverydenseateighto'clockbutthatithadthinnedoutbyten-thirty,speakingofthetrafficasifitwereanenduringobjectundergoingchangesinoneofitsproperties,justaswemightsaythataboulderhaswarmedupinthemorningsun.Butthetruth,orsomethingnearerthetruth,isthatthereareotherandfewercarsonthehighwayatten-thirtythantherewereateight.

Amoreelaborateandinstructiveexamplemayalsobedrawnfromthehighway.Alineofcarsisstoppedatatrafficsignal.Thelightturnsgreenand,aboutasecondlater,thefirstcarinlinebeginstomove,leavingagapbetweenitselfandthenextcar.Thesecondcar'sdriver,joltedfromhisorherreveriebythesightofthefirstcarinmotion,drivesoffaswell,againwithaboutasecondofdelay,andsoon.Ateachinstantthereisapointalongthelineofcarsononesideofwhichtheyarerelativelyfarapartandmovingandontheotherbumper-to-bumperandatrest.Thispointistobefoundfartherbackfromthetrafficsignalastimeelapses.WhatIhavejustgivenisalower-level

descriptionofthephenomenon.Butwecanassignavelocitytothepointofdemarcationandgiveitaname:Wemaycallitapulse,aspecialsortofwaveform.Describingthesameprocessnowinupper-levellanguage,wemaysaythatawaveorpulseofdecompressionmovesbackalongthelineofcarsatarateofaboutfourmeterspersec-

ond.Nowalineoftrafficisonlyonetypeofmediuminwhichwavemotioncanoccur,andeachmediumhasitsowncausalmechanismwherebywavesformandpropagate.Butthetrafficwaveservesaswellasanyotherexampletoillustratethefactthat,inanatomisticreconstructionoftheworld,wavesarenotthings.Inreductionisticscience,justasinordinaryspeech,wemaintainthesortofdistinctionthatappearsonthepagesofanyprinteddramaoronanyplaybill:Wespeakoftheactors,andwespeakoftheiractions.Theactorsaretheentitiestowhoseexistenceourtheoriescommitus;theyarereferredtobythenounsofoursuitablypurgeddescriptions.Thestorywetell,fullofincident,isthestoryofthosethings.Accordingtotheatomistparadigm,itwouldbewrongtolistwavesamongthedramatispersonaeofthecosmicdrama;instead,theyshouldbecountedasactivitiesperformedbythetrueagents,theatoms.

Thisisnottosaythat,givenourepistemologicalconnectiontotheworld,allwavesaredeliberatelyhypostatizedprocesses,astrafficwavesclearlyare.Somewavesareperceivedmoredirectlythanthemediainwhichtheymove,sotheyaretakenbyus,unreflectively,tobesubstantialentities.Theripplesinthesurfaceofanotherwisecalmpoolattracttheeyemorethandoesthewaterwhosedistortionstheyare.Butaswereconstructtheworldintheorythisdistinctiondisappears.Oursenses,connectedastheyaretothecausalinfluencesofourenvironment,sometimesleadustorespondtosuchtransientconfigurationsaswavesasiftheywereconcretethings.Werespondtoatravelingwavejustaswedotoamovingswimmer,byshiftingourgazehorizontally;but,whenwefollowawave,theonlyobjectsengaginginhorizontalmotionareoureyes.

Livingorganisms,consideredasarrangementsofparts,aremorelikewavesthanlikerocks.Takeasingle-celledorganism.Astheprocessesofmetabolismproceed,withasteadyimportingofnutrientsandexportingofwastes,notmuchremainsatalatertimeofthematerial

thatoncecomposedthecell,evenifithasdonenothingsodrasticastoreproducebyfission.Justasaparticularwavecrestiscomposednowofoneportionofthesurfaceoftheseaandlater,asthecrestmoveson,ofanotherportion,soanindividualcelliscomposednowofonesetofmoleculesandionsandlater,afteringestion,metabolism,andexcretion,ofadistinctsetofmoleculesofthesamekinds.Eachcell,and,there-

fore,theentireorganism,isanenduringconfigurationinthejumbleofnutrientsandwastes;itisawaveoreddyinthemolecularflux.Anorganismisacomplexdanceintowhosedynamicpatterntheatomsinsertthemselvesforatime,performingtheirintricatestepsuntil,displacedbynewcomers,theymoveontootheractionsinotherplaces.Justasawaveisproperlyunderstoodastheactionofabodyofwaterorothermedium,soalivingorganismisproperlythoughtofasconcertedmotionpassedonfromonegroupofmoleculestothenext.Themoleculesaretheactors;theorganismiswhattheydo.

UnwelcomeImplications

That,Isubmit,isinroughoutlinetheprogramofreductionisticatomism.Nowisthereanyreasontofeeluncomfortablewiththissortofreductionism,anyreasonwhywemightwelcomemitigatingconsiderations?

Thereis,andtherootsofourdiscomfortliedeepinourconceptofself.Wedonotmindbeingtoldthatourlanguageaboutthebilliardtableisonlyarough-and-readyapproximationtothetruth,aconvenientaccommodationtoourperceptualorgansandareflectionofourlimitedinterestintheeventsonthetable.Wedonotevenmindbeingtoldthatweourselvesaremadeupofallmannerofwonderfulmechanisms,ofpipes,bellows,pumps,andvalves:Suchknowledgeinitself,takenasaddingtoourfundofself-knowledge,mightonlyincreaseoursatisfactioninourselves,showingthatweare''fearfullyandwonderfullymade."Thetroubleariseswhenwearetoldthatthestoryaboutpumpsandbellowsisnottobeaddedtothestorieswealsotellaboutdreamsandemotionsbuttosupplantthem.Wearewillingtoconceiveofourselvesasthinking,feeling,andwillingbeingswhohappenalsotobemadeupofcellsandfluidsorofatomsandmolecules;whatwefinddistastefulisthesuggestionthat,althoughwemaysaythatwearesmellingrosesorbaskinginthesun

oropeningadoor,thesedescriptionsofourselveslieconsiderablyfartherfromthetruththanthelower-levelaccountsthataretoreplacethem,that,inshort,whatisreally,ormorenearlyreally,goingonistobetoldinsomestoryaboutcellsandtheirways.

Whatitcomesdowntoisthis:Asintheoryweconstructthe

worldfromitsparts,wefindourselvesgreatlyinconveniencedbyhavingtorecordtheactionsofamultitudeofatoms.Tosimplifythetaskofstorytelling,weadopt,whenpossible,theexpedientofattachingnamestocollectionsoflargenumbersofatoms,treatingthesegroupsasmodules,ashonoraryindividuals.Inthiswaythenamesoftheobjectsofeverydayexperiencearebroughtbackintothenarrative,buttheyfunctionthereonlyasaconcessiontothedemandsofeconomy.Atermlike"theeight-ball"isnowseentobejustanameweapplyforconveniencetoacertainsetofatoms,anditistheatoms,nottheball,thatareconcretelyreal.Asrealistsaboutatomswehavehadtobecomenominalistsaboutbilliardballsandaboutourselves.Infact,thesituationissomewhatworsewithregardtolivingorganisms,fortheyturnout,onthisreconstructionoftheworld,tobeattworemovesfromtheactualagents.Livingsystems,alongwithmanyothersortsofentity,arenotevenconcretesetsofatoms.Rather,theyturnouttobemereconfigurationsorpatternsinthefluxofmaterialparticles:Theyturnouttohave,inshort,theontologicalstatusofwaves,ofbaseballteams,andofsocieties.Yet,onefeels,ifanythingisconcretelyrealnotjustanabstractionitisone'sself.

Accordingtothestandardatomistparadigm,weapproachclosertothewaythingsarewhenweleaveoffspeakingofacomplexsystemanditsactionsandbegintospeakofthesystem'spartsandtheiractions.Regardlessofwherethisprocessofreductiveexplicationmayendandtheendisnotinsightthisgeneralprogramforunderstandingtheworldcommitsustotheviewthatcomplexsystemsarenotthemselvesthetruecausalagentsintheaffairsoftheworld.Butthisviewisasourceofperplexity:Humanbeingsarecomplexsystemsofparts;andifhumanbeingsarenotseenascausalagents,howcantheyberegardedasmoralagents?Ifwearemechanismsinthisveryliteralsense,thenwhatwedoisinfactmerelywhattheatomsdoastheyflowthroughthedynamicconfigurationthatbearsourname;how,

then,canwebeeitherpraisedorblamedforwhataresimplytheanticsofourparts?

Theconflictbetweenatomismandourintuitionsabouthumannaturecentersonthequestionofunity.Ourconceptofinnerunityspringsfromwhatweexperienceofourselves,yetthemechanistpicturehasroomonlyforthesortofexternalunity

Rousseaugrantstoastate:"Withrespecttowhatisexternaltoit,itbecomesasimplebeing,anindividual"(1791,1947,p.17).

Wemaybetemptedtosupposethattheschemeoforganizationofacompositesystemforgesaninnerunityoutoferstwhileindividualparts.Thetemptationarisesbecausewetendtothinkofsuchorganizationalpatternsonthemodelofhumanplansanddesigns:theblueprintsforabuilding,thescoreofaconcerto,thewiringdiagramofanelectroniccircuit,thesequenceofcallsforasquaredance.Throughthecreativeagencyofhumanbeings,allofthesepatternsplayanactiveroleinconstitutingthesystemsthatembodythem.Theatomistprogramrejectstheseanalogies.Everygroupofparticlesmustdisplaysomepatternorother,mostofwhich,likethepatternofarrangementoftherocksinaminetailing,failtoholdourinterest;butallpatterns,eventhosedisplayedbytheatomsmomentarilycomposingahumanbeing,mustberegardedasincidentalresultsofthebehavioroftheparticles.Theatomsactaccordingtotheirsimplelaws,regardlessofsetting,lavishlygeneratingpatternsofmanysorts,noneofwhichhasanycausalroletoplayintheworld'saffairs.

IfweareunwillingtoplaceourselvesatthemetaphysicalcenteroftheuniverseandastheheirsofCopernicusandDarwinthatisjustwhatweareunwillingtodothenweareobligedtoconcedetorivers,trees,andotherexternalobjectswhatweclaimforourselves:Ifwehaveintrinsicnaturesifwearewhatweareinourselves,apartfromtherelationswesustainwithotherthingsthenthosethingsmusthavetheirintrinsicnatures,too.Butscientificrealismalsoinsiststhattheirnaturescanbeknown.Takentogether,thesetwoassumptionsmeanthatourdescriptionsoftheinnernaturesofexternalobjectsoughttoserveasmodelsofthedescriptionsweapplytoourselves.Butthemodelrepels.Wefindoncloseinspectionthatexternalthingsareeitherpluralitiesofatomsorwavelikepatternsinthefluxofatoms;thattheyarepluralitiesinthemselvesandunitiesonlyinthewaywe

thinkofthem.Then,givenourmodestassessmentofourplaceinthemetaphysicalschemeofthings,whatwesayabouttheinnernatureofotherorganismswemustsayalsoaboutourselves.Thatmeansthatwetooareunitiesonlyintheregardofotherbeings;weonlyappearasunits.Yetourdeepestintuitionsofselfinsistotherwise.

Letusnowconsiderwhatmannerofreplymaybemadetothe

argumentforreduction.AsIhaveformulatedit,theargumentrestsonseveralassumptionsaboutthenatureofscience,aboutthenatureofcommonsense,andabouttherelationbetweenourknowledgeoftheworldandtheworlditself.Letmesurveythoseassumptionsmorecloselyinordertoexposepointsintheargumentthatmaybevulnerabletocounterattacksofonesortoranother.

AssumptionsofEliminativeAtomism

1.Inposingtheproblem,Ihaveassumedthatscientifictalkabouttheworldisofapiecewith,thoughanextensionof,ourcommonsensetalkabouttheworld.Ihaveassumedthatanyscience,andinparticularphysics,aimstoproduceadescriptionofthewaythingsare;thisdescriptionmaybemorepreciseandmoredetailedthanourordinarydescriptionsofthings,butitisintendedtobealiteraldescription.

2.Theproblemwasposedagainstabackgroundofcommonsenserealism,whichincludesacommonsense,prescientificvarietyofatomism.Thiscommonsenserealismis,simply,abeliefinaknowablebutobjectiveworld.Theworldisobjectiveinthissense:Whatissoisquitedistinctfromourknowingitandfromhowwecometoknowit.Theexternalworld,inthisview,isnotinextricablyintertwinedwithhumanaimsandattitudes.Thingsintheworldarewhattheyareindependentlyofwhatwemaythinkofthem,whatweintendtodowiththem,orhowwecomparethemwithotherthings.Andcommonsenseatomismrequiresustospellouttheintrinsicnatureofanythingintermsofitscompositionandstructure.Initself,aparticularwallisjustagroupofstonesinadefinitearrangement.Alandholderwithintentionsofhisownputthemthere,sothewallisalsoaboundarymarker;butthatisnothingtothatpileofstones.Localsweetheartssometimesholdclandestinemeetingsthere,sothewallisalsoatrystingplace;butthatisnothingtothatpileofstones.

Whenwecallitatrystingplacewemayseem,fromthegrammaticalsimilarityofthetwosentences,tobedescribingitinthesamewayaswhenwecallitanarrangementofstones.Butifweholdtocommonsenseatomism,wedonotintendthetwosentencestodothesamesortofworkatall.Incallingthewallapileofstoneswetellwhatitis,objectively,initself,whereasincalling

itatrystingplacewearesayingsomethingaboutthehabitsofloversinrelationtothosestones.

Onewaytosaywhatsomethingisistotellwhatkindofthingitis.But,accordingtocommonsenseatomism,thekeytoanyparticularthing'sintrinsicnatureisitscomposition:Wesaywhatitiswhenwetellwhatpartsitiscomposedof,howtheyarearranged,andwhattheydo.Forexample,supposesomeone,lookingupintothesky,remarksthatsheseeswhatlookslikeadark,undulatingribbonmovingnorthataconsiderablealtitudeandaskswhatitis.Anornithologistmayinformherthatitisacollectionofgeeseflyinginformation.Bothparties,iftheyholdtothecommonsenseviewoftheobjectiveworld,wouldfeelsatisfiedthattheornithologisthadproperlytoldwhattheobjectreallywas,initself.Hemightalsohavecalleditasignofspring,butthatwouldhavebeenaquitedifferentsortofreply.Theornithologist'sactualreplywasnot,ofcourse,asdetailedasitmighthavebeen,thoughdetailedenoughtosuittheoccasion.Butsupposethequestionerhadpersistedandaskedwhatagooseis?OnewaytoanswerwouldbethemethodofLinnaeus:Tellherthatagooseisaspecialsortofbirdwithacertainsetofdistinguishingcharacteristics.Butsupposetheornithologisthadbeenpressedtosaywhatanindividualgooseisinitself.Hemightthenquiteproperlyreplythatitisanarrangementofbones,muscles,feathers,andsoon,actingassuchthingswillact.Thisreplywouldshowthesamespiritashisreplytothequestionabouttheribbonintheskyhewouldbesayingwhatsomethingisbytellingwhatcomposesit.

Dependinguponthesocialcircumstances,oneoranothermethodofdescribingathingmaybetheappropriatewaytosaywhatitis.Ifthethingisunfamiliarbutmadeupoffamiliarobjects,wenaturallyspecifythesecomponentsandtheirarrangement.If,however,theobjectitselfisaninstanceofafamiliarkindofthing,wemore

naturallyspecifythekind.Wenaturallycharacterizeaparticularforestasagroupoftrees,ratherthanasaninstanceofvegetativegroundcover,thoughusuallywecharacterizeaparticulartreeasaninstanceofitskindoftree.Butthegeneralknowledgepossessedbythepeoplewhoaskuswhatthisorthatobjectisandtheirintentionsinaskingarenothingtothoseobjectsinthemselves.Whenwecallaforestaninstanceof

vegetativegroundcoverwealludetothefactthattherearemanyotherobjectssimilarincertainrespectstothisone;wedothesamewhenwecallanotherobjectamapletree.Buttosaythataparticularforestisagroupoftreesarrangedinacertainwayandtosaythataparticulartreeisagroupofcellsinacertainarrangementistospecifywhatthoseobjectsareinthemselves,independentlyofourproclivitiesforcomparingandclassifying.Whenweidentifysomethingasaninstanceofakindwechooseasubsetofallthethingswecouldsayaboutitandwelikenittootherobjectsaboutwhichthesamethingsmaybesaid.Wemighthavecalledthetreeavascularplantandtheforestabattleground.Ourchoiceofkinddependsonourpurposesinmakingthedescription.Butwhatanindividualthingisintrinsically,inallitsindividuality,isacertaingroupofpartsarrangedandinteractinginacertainway.

3.If,accordingtocommonsense,weareabletosaywhatthingsareinthemselvesbytellingwhattheyarecomposedof,andifscienceiscontinuouswithcommonsense,thenwearelednaturallytoathirdassumption,orsetofassumptions,formingpartofthebackgroundoftheproblemIhaveposed:Ihaveassumedtheviabilityofscientificatomismasaprogramforspellingoutthenatureofthings.Aswecontinuetoprobeintotheinnercompositionandstructureofthings,wemovebydegreesfromwhatisobviouslyprescientificcommonsensetowhatisobviouslyhighlyscientific.Whataboutaparticularmuscle?Whatisitinitself?Wehaveanearlycommonsenseanswertothat:Itisacollectionofcellsandintercellularfluids.Andwhatofaparticularcell?Andwhatofthatcell'snucleus?Andwhatofaparticularchromosome?AndwhatofaparticularDNAmolecule?Andwhatofaparticularcarbonatom?Thesamesortofanswerisgiventoeachofthesequestions.Soaccordingtothisviewofanobjectiveworld,thewaytospelloutwhatsomethingreallyisinitselfwhichisnotthesameastellinghowweknowaboutit,orwhatwehopeor

intendaboutit,orwhatrelationsitbearstootherthingsistosaywhatcomposesit.Andintheprogramofscientificatomismthemostaccurate,themostthoroughspellingoutofwhatsomethingismustalwaysbeastatementthatdescribesitasanarrangementofitsultimateparts,interactingintheirownways.Theseultimatecomponentsformtheonlytruly

naturalkinds.Onemapletreeisnotexactlylikeanother,norareanytwophloemcellsquitealike,buttheatomsofagivenkindaredistinguishedonlybytheirspatiotemporallocations.

4.Finally,theprogramofscientificatomismadmitsofonlyonekindofeffectivecausation:physicalcausation.Everyinstanceofcausalactionofonethingonanotheristheactionofultimateatomuponultimateatom.DavidHume'sindictmentofcausationpersistseveninthefaceofthemechanistictreatmentofcauses.Thenotionofphysicalnecessityorcausalconnectionremainsasmysteriousasiteverwas.ButtheforceofHume'sskepticismcanbemoderatedconsiderablybyamechanisticphilosophy.Likeasavingsandloanassociation,mechanisminvitesustoconsolidateourdoubts.Thelinkbetweensmokingandcancercanbeclarifiedbythediscoveryofcarcinogenicsubstancesintobaccosmokeandtheelucidationoftheactionofsuchmoleculesonlivingcells.Theactionofonemoleculeonanotherisclarifiedbythetheoryoftheelectronpairbond.Theelectrostaticattractionbetweenprotonsandelectronsisexplainedbytheexchangeofvirtualphotonsbetweenthem.Inthisway,thecausalmysteriesofoneleveloforganizationaredispelledbythecausalprocessesatthenextlowerlevel.Asaresultofthisreductiveexplanationofcausation,themysteriesareconfinedtotheultimatelevelofreduction,wheretheyremainultimatelymysterious.Tounderstandanyinstanceofeffectivecausationonemustthinkoftheultimateatomsasthecausalagentsbecausethatisthewaythingsare.

SixRejoinderstoAtomism

Thissetofassumptionsmaybeassaultedatseveralpoints,twoofwhichlieoutsidethescopeofthisessay.First,onemightattackrealismbyarguing,forexample,thatourcommonsensetalkabouttheworldcarriesnoontologicalclaims,thatitisonlyawayoforganizingourexperiences.Second,whileretainingarealisticattitudetowardthe

world,onemightrejectatomism,anontologicalprogramofconcretematerialparticulars,andcampaignforsomerivalmetaphysicalprogram(Campbell1976).Ishallnotconsidereitheroftheselinesofattack;indeed,Iaimtoseehowwelltheprogramofcommonsenserealismcoupledwithatomisticreductioncanbemadetowork.Third,without

discardingcommonsenserealismorcommonsenseatomism,onemighttrytodriveawedgebetweenscienceandcommonsense,notbymodifyingtherealistclaimsofcommonsensebutbysettinglimitsonwhatsciencecanclaimtotellusaboutthenatureofthings.Thiscounteroffensive,launchedbyGilbertRyle(1954),willformthesubjectofchapter3.

Fourth,onemightcomplainthatthemechanistsresttoocomfortablyontheirlaurels.Thereductionofmacroscopicthermodynamicstostatisticalmechanics,thoughanadmirableachievement,providesnomodelforthereductionofsuchupper-levelconceptsaspurpose,goal,andfunction;hence,itdoesnotjustifytheexpectationthattheycanbegivenreductiveexplications.Chapters4,5,and6willbeconcernedwithrivalapproachestotheexplicationofgoal-directedness:areductive,cybernetictheory,originatedbyArturoRosenblueth,NorbertWiener,andJulianBigelow(1943);andanonreductive,selectionisttheory,proposedbyWilliamWimsatt(1972.).

Fifth,withoutattackingrealism,ordenyingthecontinuityofscientificwithcommonsensedescriptions,orquestioningtheproprietyoftheatomistprogram,onemighttrytomitigatereductionismbyshowingthatthereareobjective,thatis,non-anthropocentric,reasonsforlistingthemacroscopicobjectsofeverydayexperienceamongthedramatispersonaeofthecosmicdrama.ThisisthelinetakenbyJerryFodor(1968;1975)inhisdefenseoftheautonomyofpsychology.Brieflysummarized,Fodor'spointisthatthelawsofupper-levelsciences,formulated,ofcourse,intermsofupper-levelthings,areassertionsabouttheworld,yettheyareincapableofbeingexpressed,atleastinclosedform,intermsoftheentitiesoflowerlevels.Therefore,toexcludenamesforupper-levelentitiesfromourvocabularyisnotmerelyinconvenient;todosoistorenderourselvesunabletoexpresssometruthsaboutthenatureofthings.Fodor'ssuggestion,withapplicationsofitbyDavidHull(1974)andWilliam

Wimsatt(1976),willformthesubjectofchapter7.

Finally,onemighttrytogroundadefenseofeverydayobjects,oratleastofcertainspecialthingssuchascentralnervoussystems,ontheholisticfeaturesofquantummechanics.Thisproposedsolutiontotheproblemposedbyreductionismwouldnotthreatenanyoftheassumptionslistedabove;rather,itwouldshowthatatomism,ifpursuedfarenough,producesitsown

answerbyjustifyingourtreatingcomplexsystemsasunitarywholes.Indeed,someinterpretersofquantummechanicsseeinitaradicalchallengetotheontologyofmaterialism,bywayofsupportformind-matterdualism.Argumentsforthesupposedholisticanddualisticfeaturesofthequantumtheorywillbeconsideredinchapters9and10.

ThreeReductionandCommonSenseCouldtheproblemIhaveposedinthepreviouschapterbeonlyapparent?Wouldarightassessmentofthenatureandlimitsofthescientificenterpriseshowthatwhatittellsusabouttheworlddoesnot,afterall,clashwithourcommonsenseformulationsofthewaythingsare?GilbertRyle(1954),defendingthelegitimacyofourcommonsenseviewofthings,suggeststhatreductionisticscienceonlyseemstochallengeourcommonsense.UnlikethephilosopherswhomIshallconsidernext,Rylefeelscalleduponneithertoenlistinabattlebetweenscienceandcommonsensenortoofferhisservicesasanarbitrator,becauseinhisviewthereisinfactnofeud:Thenotionthatscienceconflictswithcommonsensecouldariseonlyfromamistakenideaastowhatscienceisabout.

Ryle'sconjectureispresentedin''TheWorldofScienceandtheEverydayWorld"anditssequel,"TechnicalandUntechnicalConcepts"(1954).IntheseessaysRyleoffershisreadersaseriesofexamplesandsuggestiveanalogiesandleavesituptothemtodeterminehowtheanalogiesmayapply.FormypurposesRyle's

allusivenessisavirtue,foritrequiresmetofillouthispartialrecipeforanargumentbysupplyingsomeingredientsofmyown.Itallowsmetoraiseandproposeanswerstoseveralquestionsabouttheconnectionsbetweenscienceandcommonsense,ofwhichpossiblyonlyonemaycaptureRyle'sintendedpoint,butallofwhichneedtobeairedandsettled.IshalltakeupRyle'schallenge,then,aimingattwoobjectives:totesttheargumentofthepreviouschapterthatscientificrealismclasheswithimportantcommonsenseintuitions,andtobuildafoundationfortheargumentsofsucceedingchaptersbyspellingouthowatomismcanaccommodatesomeofthestandardcomplexitiesbuiltintoourordinarytalkabouttheworld.

Ryledistinguishesthecosmos,theworldwealllivein,fromthenarrow''worlds"ofspecialistsofvarioussorts.Examplesofspecialworldsaretheworldofpoker,theworldofaccounting,andtheworldofstampcollecting.Thoughcertainlypartsofthecosmos,thesespecialworldsstandapartbecausetheyaretheprovincesofspecialistswiththeirownaims,vocabularies,andtechniques.MostsignificantlyforRyle'scase,thepracticeofthesespecialtiesoftenleadstotheintroductionoftechnicalconcepts,bywhichheseemstomeanconceptsthatariseinthecontextof,andapplyto,theaimsandtechniquesofthespecialareaofinterest.Ryleoffersanumberofexamplesofwhatappearsuperficiallytobeclashesbetweenclaimsmadeinthecontextofdistinctspecialworldsbutwhichareeasilyseennottobeclashesatall.Letusconsidertwoofhisexamples.

Aparticularhandofplayingcardsmaybesaidtocontainhonorsintrumporaroyalflushbutnotatthesametime.Whereaseitherofthesedescriptionsmaybetrueofthehand(dependingonwhetheritarisesinthecontextofbridgeorofpoker),bothcannotbetruesimultaneously.Butthatdoesnotmeanthatbridgeandpokerconflict;itmeansonlythatonecannotplaybothgamesatonce.Theworldsofbridgeandpokeroverlap,becauseeachinvolvesthestandardpackof

playingcards.Inthatsensethetwoworldsarerelated,butnotinsuchawaythattherecouldbeaclashbetweenpokerstatementsandbridgestatements.

Anaccountantmayrecordthebusinesstransactionsofacollegelibraryandproduceatidyandpleasingbalancebetweentheincomefromendowmentsandfinesandtheexpendituresforbooks.Whattheaccountantsaysaboutthelibraryisormaybe

trueofthefiscalaspectsofthelibrary.Buttheaccountant'struthcouldnotclashwithwhatanundergraduatesays,forthestudentisconcernedwiththesubjectmatterofthebooks,nottheirprices.Neithersetofstatementsaboutthelibraryneedbefalse;yeteachisirrelevanttotheother.

Insomesuchway,suggestsRyle,theclaimsmadebyscientistsaboutobjectsintheworldbearuponoureverydaydescriptionsofthings.JusthowtheanalogyisaptRyledoesnotsay,soIshallexamineinturnseveralwaystheanalogymightbeapplied,usinghintsgleanedfromthetwoessays.

Rylesaysthatappearanceofaclashbetweenscienceandcommonsensedoesnotoccuronallfronts.Thefindingsofbotanists,forinstance,orofastronomers,donotevenseemtochallengecommonsenseinanyimportantway.AccordingtoRyle,thetroubleseemstoarisewhenweconsiderthephysicsoftheverysmall.ButasIhaveformulatedtheproblem,warbreaksoutlongbeforethefrontiersofthelightmicroscopehavebeenpassed.Commonsenseintuitionsarechallengedwhereversciencetellsusthatanordinaryobject,asitisinitselfapartfromconsiderationsaboutitsrelationstootherthingsortohumanbeings,istobeunderstoodasnothingmorethanasetofinteractingparts,evenwhenthosepartsareorgansorcells.Ryledoesnotsaywhetherhisanalogiesaretobeappliedtosciencesofallsortsoronlytochemistryandatomicphysics.Butsomeofhisanalogiesseemtometoapplyrathernicelytosomeofthescienceshesinglesoutasobviouslycompatiblewitheverydaydescriptionsofreality,soIsupposeheintendstosuggestthattheworldofanyscience,notjusttheworldofatomicphysics,isaspecialist'sworld.Moreover,onlyifRyle'sconjectureisconstruedinthisbroadsensecanitserveasapossibledissolutionoftheproblemofreductionism,sothatishowIshallconstrueit.

How,then,areRyle'sanalogiestobeapplied?Inwhatrespectsarehisexamplesliketheconfrontation,ormockconfrontation,betweenscienceandeverydayexperience?

Specialists'Worlds

Onefeaturethatmaydistinguishaspecialworldisitsspecialmatter.Philatelistsoperateinaseparateworldatleastpartlybecausetheydealwithobjectsofaspecialsort,namely,stamps.

Likewise,entomologistsstudyinsectsbutnotsnakes,andastronomersobservestarsbutnotbeetles.However,thatcannotbethewayRyle'sanalogiesaretobeappliedtothecaseatissuebecause,ashepointsout,thedisciplineatthecenterofthestorm(orseemingstorm)isatomicandsubatomicphysics,whichisconcernedwitheverythingthereis:rocks,insects,plants,andpeople.Insuggestingthattheclaimsofphysicsdonot,afterall,clashwithoureverydayviewsoftheworld,hedoesnotwishtosuggestthatphysicistsareconcernedonlywithspecialsortsofobjectstotheexclusionofothers.

Anotherfeaturethatsetssomespecialworldsapartistheirconcernwithhumanconventionsandrulesofbehavior.Thatisclearlytrueoftheworldsofvariousgames.Pokerisaworlduntoitselfbecausethegameisasetofarbitrarysocialconventions,apurelyformalactivity.Althoughsnakeswouldstillcrawlevenifherpetologistslostinterestinthem,insidestraightswouldsimplyceasetoexistifpeoplestoppedplayingpoker.Whatpokerplayerssaydoesnotchallengeoureverydayexperienceoftheworldbecausepokertalkisaboutaworldformedbythepeoplewhoplayit.Aspokerplayersconcentrateontheartifactsofthegamingtable,soaccountantsdealwiththeartifactsofthemarketplace.Thewaywehandlemoneyisgovernedbysocialconventions;itissomethinglikeagame.Ifhumanbeingsceasedtotakeaninterestinmoneyandcontractualobligations,then,thoughwheatandironwouldremain,debitsandcreditswouldfadeaway.

CouldthatbethewayRylewishesustolookatscience?Certainlyonecanfindinstancesofthissortofthinginthevarioussciences:Theconceptofthestandarddeviationofasetofmeasurements,forexample,appliestothetechniqueofmeasuring,nottotheobjectsonwhichmeasurementsaremade.Ifpeoplegaveupmeasuring,therewouldbenomorestandarddeviations.But,unlikechessandpoker,scienceisnotapurelyformalactivity,andunlikeaccounting,naturalsciencedoesnottakehumanconventionsasitssubjectmatter.

ConceptsthatapplymerelytoscientifictechniquearenottheonesRyleisorshouldbeconcernedabout.

ButthereisanotherwaythatwemayconsiderRyle'sparableofacollegelibraryasananalogytothedistinctionbetweenscienceandcommonsense.Theaccountanthassomethingtosayabouteverythinginthelibrary;whatsetsherworldapartisnotaspe-

cialsetofobjectsofinterestbutaspecialwayofbeinginterestedinthem.Sheisconcernedonlywiththefiscalaspectsofthecollege,with,forexample,thepriceofeachofthelibrarybooksbutwiththeliteraryvalueofnone.PartofRyle'squarreliswithacertainviewofthenatureofatomicphysics,which,ashestipulates,appliestoeverythingthereis.Soitseemsclearthathewishestosuggestthat,liketheaccountant,anatomicphysicistisconcernedonlywithsomeparticularaspectorfeatureofeveryobjectintheworld.

Whatcouldthatspecialfeaturebe?What,inRyle'sview,istheatomicphysicist'speculiarperspectiveontheworld?Againwemustrelyonhintsgleanedfromhisexamples,butitseemsthathehasinmindthephysicist'scharacteristicpreoccupationwithmattersquantitative.Ibasethisguessprimarilyontheopeningparagraphof"TechnicalandUntechnicalConcepts.""Ascientifictheory,"Rylesays,

hasnoplaceinitfortermswhichcannotappearamongthedataortheresultsofcalculations....Sincescientifictruthsareaboutwhatcancarryandbecarriedbycalculations,colours,tastesandsmellswhichcannotbesocarriedmustbelongnottothefactsofphysics,butelsewhere,namelyeithertothefactsofhumanandanimalphysiologyortothefactsofhumanandanimalpsychology.[1954,p.82]

LaterRyledeniestheconsequentofthatsentencebutallowstheantecedenttostand.Thepassagequotedshowsmostclearly,Ithink,howRyleintendshisanalogiestobeapplied,butthereareothersignsthatpointinthesamedirection.Oneofthemisthefactthattheaccountant,intheonlyexamplethatseemsatallclosetothecaseofatomicphysics(aswehaveseen),isalsoconcernedwithaquantitativeaspectoftheworld,with"whatcancarryandbecarriedbycalculations."Theaccountantspeaksnotaboutlibrarybooksthemselvesbutonlyabouttheir(numerical)prices.Similarly,accordingtoRyle,physicaltheorists"donotdescribechairsandtables

atall,anymorethantheaccountantdescribesbooksboughtforthelibrary"(1954,p.79).AnothercluethatnumberandcalculationarethekeystoRyle'sanalogiesturnsupinalaterchapter,''Perception,"inwhichheofferstodefendcommonsensenotionsofperceptionfromtheonslaughtsof"thinkerswhowishtomaintainthepre-eminenceofmathe-

maticalknowledgeoverotherbeliefs"(p.94).Stilllater,in"FormalandInformalLogic,"hereferstotheearlierchaptersasinvolving"litigations"between"mathematiciansandmeninthestreet''(p.111).Ryleseemstobesayingthis:Scientistsperformmeasurementsontheobjectsofeverydayexperience,therebygeneratingnumericaldata.(See,forexample,howhecontrasts"thermometer-temperature''and"warmth,"p.91).Scientificdiscourse,then,isaboutthesenumericaldataand,properlyunderstood,doesnotprovidedescriptionsoftheobjectsfromwhichthedatahavebeenextracted.Anysuggestion,then,thatscientificstatementscouldconflictwithcommonsensetalkaboutobjectslikechairsandtablesmustrestonafailuretodistinguishtalkaboutthenumericalartifactsofmeasuringfromdescriptionsofactualthings.

Whenweexplainthefuzzyappearanceofadandelionheadbypointingoutthatclosescrutinyshowsittobemadeupofamultitudeoftinywhitefilaments,weareengagedinonesortofcommercewiththeworld,Ryleseemstoargue,butwhenweexplaintherigidityofabarofsteelbypointingoutthatindirectevidenceobtainedbymeansofinstrumentsotherthaneyesormicroscopesshowsthebartobecomposedofatomsarrangedandinteractingincertainways,thenourcommerceisofquiteanothersort.Abotanist'sclaimaboutadandelionisanactualdescription,butametallurgist'sclaimabouttheatomiccompositionofabarofsteelisneitheradescriptionnoramisdescriptionofthebar;itis,Ryleseemstosay,astatementaboutthenumericalresultsofmeasuring,justaswhatanaccountantsaysisaboutpricesandneitherdescribesnormisdescribesbooks.

ContinuityofScienceandCommonSense

Itisnoteasytoassess,muchlesscriticizeortrytoreplyto,aseriesofsuggestionsbackedupbyplausibleanalogies.Letme,however,maketheattemptbyproposingsomesuggestionsandanalogiesofmyown.

Doesthescientists'preoccupationwithnumericaldatasettheirworldapart?Considerthisexample.Aphysicistwithapenchantformathematicalspeculationandahearty,nonmathematicalcricketplayerarebothobservingahutwithonedoorandnowindows.Astheywatch,threepersonsenterthehut,andaftera

shorttimetwoemerge.Thephysicistperformsamathematicaloperationonhisdataandconcludesthatonepersonremainsinside.Thecricketerrunsuptothehut,peersthroughthedoorway,andseesonepersoninside.Bothnowvoicetheclaimthatthehutcontainsoneperson.Ryle'sargument,asIhaveinterpretedit,wouldleadustosaythatthecricketer'sclaim,basedasitisonthesortofevidencethatanyable-bodiedpersoncouldobtain,isabouttheworldwealllivein,whereasthephysicist'sclaim,basedonabranchoflearningrightlyshunnedbythecommonman,isaclaimaboutthespecial"world"ofthephysicist;itisaboutonlythosepeculiarquantitativeaspectsoftheworldthatintriguephysicistsandboretherestofus.Clearly,thatisnonsense.Thephysicistemployednumericaldataascluestowhatwasgoingonintheworld,butalthoughwhathesaidwasbasedontheresultsofdatagatheringitwasnotaboutthosedata.Likethecricketer'sclaim,hiswasanactualdescriptionofthehut.

Soitis,Iclaim,withatomicphysics.ThequantitativereasoningthatledDaltontoconcludethattheworldismadeupofatomswasofthesamesortas,andhardlymorecomplicatedthan,thequantitativereasoningemployedbythephysicistwatchingthehut.Andifitisnonsensetosuggestthatthephysicistintheparablewasnottalkingaboutanordinaryflesh-and-bloodpersoninthehut,itisequalnonsensetosuggestthatDaltonwasnotassertingaclaimabouttheactualcompositionofoureverydayworld.Daltonreasonedfromanarrowsetofquantitativefactsaboutchemicalreactionstoaconclusionabouttheworldweallshare.Totheextentthatheandhissuccessorsdidtheirjobproperly,theiratomsareeveryone'satoms.

IsuggestthatRylehasnotnoticedhowscientistsactuallyemploymathematicsintheirwork.Incompanywithmanypeopletowhomtheapparitionofanequationonaprintedpageisasparalyzingasthesightofaserpenttoasparrow,1hehasseenthemathematicalformulasbuthasnotheardtheextensivediscoursethatsurroundsand

interpretsthem.Itisasif,inthestoryofthephysicistandthecricketer,abystanderhadnoticedthephysicist'sscrapofpaper,onwhichthefigure2wassubtractedfrom3buthadfailedtonoticethatthephysicist'saim,inperforming

1/IdonotknowhowRylefeltaboutmathematics,butthisaccuratelydescribesmanyofmyfriends.

thisfeat,wastodescribethecontentsofthehut.NeitherRylenoranyoneelsewouldclaimthatthephysicistwasmerelyabstractingoutoftheconcretesituationapurelyformal,mathematicalstructureinkeepingwithhisprofessionalpreoccupationwith"whatcancarryandbecarriedbycalculations."Todosowouldbetomistakethephysicist'smeansforhisends:Hedidnotscantheworldinordertopulloutofitamathematicalformula;rather,heusednumericaldataascluesandaformulaasanaidtoreasoning,inordertoaugmenthisdescriptionoftheworld.Rylewantstosetupacontrastbetweentheviewsof"mathematiciansandmeninthestreet."Butphysicistsarenotmathematicians.Askanymathematician,oranyphysicist.Mathematiciansandpokerplayersmakenoattempttodescribethematerialworld;physicistsandmeninthestreetdo.

Itseemsthatamistakenviewoftheusesofmathematics,whichwouldtemptnooneinasstraightforwardacaseasdeterminingthecontentsofahut,hasbemusedmanypeople,Ryleamongthem,whentheyconsiderthelessreadilyaccessiblefieldofatomicphysics.Rylewouldsay,ofcourse,thatanornithologistwhointerpretsthesightofablack"ribbon"intheskyasaflockofgeesearrangedinaVspeaksinthesamematter-of-facttoneusedbythephysicistandthecricketerwhenspeakingaboutthehut,buthewantstorejectthesuggestionthatDalton'ssuccessorsusedthattonewhenclaimingthatanironbarreallyisalargenumberofironatomsarrangedinalattice.Iclaimthatnodistinctionbetweenthetonesofvoiceofatomicphysicistsandmeninthestreetcanbebasedonthefactthattheformersometimesreasonfromnumericaldatabymeansofmathematicalformulas.

Theory-LadenTerms

Rylealsosuggeststhattheclaimsscientistsmakeabouttheworldarecouchedinavocabularywhosemeaningderivesfromthewayitstermsareusedinscientifictheories.Manyofthetermsusedby

scientists,heasserts,are"theory-laden,"whereasourordinarydiscourseabouttheworldisnot.2Therefore,scientificclaimsabouttheworlddonotstandonthesamegroundas,

2/Orsome,atleast,ofcommonsensediscourseisnot.Ryledrawshiscontrastbetween"thetechnicalconceptsofascientifictheoryandthesemi-technicaloruntechnicalconceptsofthepavement"(1954,p.91).

andcannotbemadetofightwith,commonsenseclaims.Thiswayofavoidingaconfrontationbetweenscienceandcommonsenseisindependentoftheargumentfromthemathematicalpredilectionofatomicphysicists,for,ifthisargumentworksatall,itdoessowhetherscientifictheoriestakeamathematicalorsomeotherform.Letusseeifitworks.

ItisimportantnottoconfuseRyle'sclaimthatscientifictalkabouttheworldistheory-ladenwiththesuggestionsoflaterphilosophers(forexample,Feyerabend1970)thatallourtalkaboutanythingwhateverisboththeory-ladenandhopelesslysubjective.Rylewishestoalignhimselfwiththemaninthestreet;atleast,hewantstodefendtheplainman'sviewthattheworldasweknowitfromeverydayexperienceisreal,nota"dummyworld"nottoberelegatedtotheinsidesofourheadsbutreallyoutthere.TheworldRyledefendsistheworlddefendedbySamuelJohnsoninhisfamousretorttoIdealism.Thatworldisasitis,regardlessofwhatwethinkaboutit;againstitwecanstubourtoesandshatterourtheories.Ryle,Ithink,wishesseriouslytodefendsomekindofcommonsenserealism;heisnotGeorgeBerkeleyrelaxinginwhiteflannels.

Howmightscientifictalkabouttheworldbeinfectedwiththeoryinsuchawayastoquarantineitfromourordinarydescriptions?Intheabsenceofworked-outsamplesfromRyle'sownpen,wemusttrytoguesswhathehasinmind.Theanalogyheoffersisthewaythetermsofbridgeandpokerareladenwiththerulesofthosegames.OfthetermsofgeneticsRylesays(1954,p.90),"Thetechnicaltermsofgeneticsare...laden...withtheluggageofgenetictheory.Theirmeaningschangewithchangesinthetheory.Knowingtheirmeaningsrequiressomegraspofthetheory."Similarly,hesuggests,knowingthemeaningof"straightflush"requiressomegraspoftherulesofpoker.Butageneralallusiontogeneticsishardlyanexample.Ryledoes,however,suggesttwospecificexamples(withoutworkingthem

out)ofwhatheconsiderstechnicalconcepts:theconceptof"lightwave,''whichhecontrastswiththecommonsenseconcepts''pink"and"blue"(p.91),andtheconceptof"thermometer-temperature,"whichhecontrastswith"warmth"(p.88).Letusseewhatcanbemadeofthesehints.Ryleissurelymistakeninsuggestingthat"lightwave"and"blue"arecontrastingconcepts,becausealightwaveisanobjectofsomesortwhereas

"blue"specifiesapropertyofobjects;surelynoonewouldbetemptedtosubstituteoneofthesetermsfortheother.Butincomparing"thermometer-temperature"with''warmth"Rylechoosesausefulexample.Someonemightinfactwishtosuggest(mistakenly,Rylewouldsay)that"thermometer-temperature"doesthesamesortofworkas"warmth''butdoesitbetter."Wecan,"saysRyle,"beseriouslyperplexedbythequestionwhetherbehindthewarmthofthebathwaterwhichthechildfeelswithhishand,theredoesnotcovertlyresidesomegranderpropertywhichhefailstodetect,namelythethermometer-temperatureofthewater"(p.88).Buttothinkthatthereisa"logicalrivalry"betweenthetwoconceptsistobemistakeninsomewhatthesamewayaswhenwesupposethatthereisrivalrybetween"trumpcard"and"queenofhearts,"accordingtoRyle.Agivenbitofpasteboardmaysimultaneouslybethequeenofheartsandatrumpcard,butthesearetwologicallydifferentsortsofconditionsinwhichacardmayfinditself.

Nowthereisasense,butatrivialone,inwhich"thermometer-temperature"illustratesRyle'spoint.Itistruethattounderstandthatthebathwaterisfairlywarmrequiresnograspofscientifictheory,buttounderstandthatitisat50°CdoesrequiresomegraspoftheconventionsoftheCelsiusscaleoftemperature.Butfromthesefactsitemphaticallydoesnotfollowthatbeingat50°Candbeingfairlywarmaretwoquitedifferentsortsofconditionsinwhichthebathwatermayfinditself.Thestatements,"Itisat50°C,"and"Itisat78°C,"thoughladenwithconventions,areneverthelessattemptstospecifymoreaccuratelythesamesortofthingwespecifyby"Itisfairlywarm"or"Itisverywarm."Thephrase"boilinghot"ismademoreprecisebutnottransformedintoanotherlogicalcategorywhentranslatedas"nearly100°C."One'saiminutteringeithersortofstatementistotellhowwarmthebathwateris.AndRyleissimplymistakeninhissuggestionthatanyonewouldfeeltemptedtothink

thatthethermometer-temperatureofthewaterliesbehinditswarmthandgoesundetectedwhenwetouchthewater.Behindthethermometerreadingliestheabilityofthewatertocausetheexpansionofmercury,andbehindthewarmth-sensationliestheabilityofthewatertocausesensationsofwarmth.Butcommonsenserequiresustotakethethermometerreadingasasymptomofthesameintrinsicpropertyofthewaterthatwarmth-sensationsare

cluesto.Thepropertyofobjectswedetectandmeasurebymeansofthermometersisthesamepropertywedetectandestimatebytouch.AsIshallargueatgreaterlengthbelow,thepropertywehavealwaysunderstoodourselvestobereferringtobytheterm"warmth"hasturnedouttobeastatisticalfeatureofthedistributionofenergyamongthepartsthatcomposewarmthings.

Sothetheory-ladennessoftechnicalconceptsliketemperaturedoesnotjustifyquarantiningscientificfromcommonsensetalk.Notonlydoesouremploymentofthermometrictermsmergecontinuouslywithouruseoftermslike"cool,""warm,"and''hot,"butwehavethesameaimaswell,namely,todescribeanobjectbyspecifyingaparticularoneofitsintrinsicproperties.

Letusmakeonemoreattempttoseewhetherthecloseconnectionbetweenscientifictermsandscientifictheoriesmayforestallpossibleconflictsbetweenscienceandcommonsense.Notethat,whenwesaythattheintrinsicpropertyofwarmbodiesthatwedetectbytouchandbythermometryisafeatureofthedistributionofenergyamongthemicroscopicparts,ourclaimisonlyasfirmasthethermodynamictheoryonwhichitrests.Scientificdescriptions,unlikethoseofcommonsense,frequentlystanduponelaboratetheoreticalfoundations;ifthetheoryonwhichascientificdescriptionisbasedshouldbeabandoned,thedescriptionmightlikewisecollapse.IsthathowweshouldinterpretRyle'sobservationthatscientifictalkabouttheworldisladenwiththeory?Wouldthatinterpretationpreventscientifictermsfromclaimingaseatonthebenchnormallyoccupiedbythetermsofcommonsense?Thefollowingsimplecounterexampleshowsthatthisinterpretation,too,failstosupportRyle'sthesis.Therearetwowaysinwhichanewplanetmaybediscovered.Onewayistolookverycarefullyintheregionoftheeclipticforapointoflightwhosepositionchangesslowlywithrespecttothebackgroundstars.Thatishowtheplanetsknowntotheancientswerefound,anditisthe

wayofcommonsense.Theotherwayistocomparetheobservedmotionsofknownplanetswiththeoreticalpredictionsofhowtheyoughttomove,givenourpresentknowledgeofthestructureanddynamicsofthesolarsystem.Then,iftheplanetfailstomoveasweexpectitto,wehypothesizethatanunknownplanetisresponsibleforthediscrepancybetweenobservationandprediction.Thatwasthemethodused

byAdamsandLeverrierindiscoveringtheplanetNeptune,amethodthatistheory-ladeninasmuchasitemploysNewton'slawsofplanetarymotion.Becausethissecondmethodoperatesbymeansofscientifictheories,ItakeittobeanexampleofthescientificwayofdealingwiththeworldthatRylewantstodifferentiatefromcommonsense.

Ryle'sdistinction(asappliedtothisexample)mighthavelookedmoreplausibleifourbeliefintheexistenceofNeptunehadcontinuedtorestonlyontheperturbationsoftheorbitofUranusandhadnotbeensubstantiatedbythetelescopicobservationsofJ.G.Galle.ButwhonowcouldseriouslysuggestthatGalle,thefirstpersontoseeNeptune,andtheancientpeoplewhofirstnoticedthewanderingsofSaturnwereengagedinaradicallydifferentsortofenterprisefromthatofLeverrierandAdams?Clearly,theywereallaskingthesamequestionsandmakingthesamesortsofclaimsabouttheworld.Theiremployingdirectvisualobservationsontheonehandandindirectones,supplementedbycarefulreasoning,ontheotherdoesnotatallservetodriveawedgebetweentheirenterprises.

IncontrasttothescienceofNewton'sday,modernsciencehasburgeonedtosuchadegreethattheordinaryeducatedpersonoftenfeelsshutoutfromthescientificenterprise.Anditistruethatscientistshaveinventedtechniquesandconceptsthataremerelytechnical,suchastheconceptsofmolalityandoftareweight.Butdothefactsthatrelativelyfewpersonshaveaconfidentgraspofmodernscienceandthatscientistsemploysomepurelytechnicalconceptsintheirworkshowthatscienceisatbottomatechnicalworlduntoitself?Surelynot.Scienceaimstofindoutwhattheworldislikewhatitismadeofandhowitworks.Andscienceclaims,rightlyorwrongly,toanswerquestionsofontologyandofcausation.

WhenWatsonandCrickfoundthattheDNAmoleculeismadeupof

nucleotidesarrangedinadoublehelix,theywereengagedinthesamesortofactivityasweretheearlymicroscopistswhofoundthatlivingtissuesarecomposedofcells;indeed,inthesamekindofactivityaswereourprehistoricancestorswholearnedthatcattlearecomposedofbones,muscles,viscera,andsoon.Thenotionofaplanksteakisabutcher'stechnicalconceptandsignifiesnothingmuchaboutthecompositionofacow.Butthenotionofaboneisnotatechnicalconceptitisas

everydayandcommonsensicalastheconceptofagrainofsand.Whenweapproachasideofbeefasbutchersdo,bearinginmindthedemandsofourcustomers,wecanseethecarcassasconsistingofsomanysteaks,chops,androasts.Butwhenweapproachitonitsownterms,carryingwithusnothingofthespecialist'stricksandproceduresbutmerelyaskingwiththecommonman,"Whatisitlike?"and"Howdoesitwork?"thenwefindittobemadeupofbonesandmuscles.

Butwhatofthismuscle?Whatisitmadeof?Theattitudeofopeninquiry(commonsenseextendedbutnotalteredinspirit)leadsustoanswerthatitconsistsofcells.Andthecell?Andthecell'snucleus?AndtheDNAmolecule?Andthecarbonatom?Allthesequestionsandtheiranswers,tentativethoughtheybe,areputforwardinthespiritofthecommonman.Theyarenotspecialist'squestions,eventhoughtheytendtobeaskedbyonlyasmallfractionofthepopulace.Whatturnsdiscourseintospecialist'slingoisnotitslimitedpopularitybutthespecialsocialcontextinwhichitresidesandthepeculiaraimsitserves.Theargotofthepokerplayeristechnicaltalkbecauseitacquiresitsmeaningfromtherulesofthegameandtheaspirationsofitsplayers.ButwhenamoleculargeneticistinquiresintothecompositionofastrandofDNA,heorsheengagesinthesamekindofactivityasonewhowonderswhatisinthesouptonightorwhethertherestaurantismadeofbrickorstone.Nearlyeveryoneknowstheslangofthebaseballdiamond,andveryfewareathomeinalaboratoryofmoleculargenetics;yettheworldofbaseballisaspecialist'sworld,andtheworldofgeneticsiseveryone's.

Ifthebusinessofscienceisthebusinessofcommonsenseinquiryintothecompositionandworkingsoftheworldwealllivein,thenwemayexpectoccasionallytoencountergenuineclashesbetweenwhatwebelievetobetrueoftheworldonthetestimonyofcurrentscientifictheoriesandwhatweholdtobetrueonothergrounds.Suchaconflict

isnotaproblemgeneratedbythepracticingofanesoterictechnique;itisgeneratedbytheworkingoutofanattitudetowardtheworldthatispartofthegeneraloutlookofWesterncommonsense.Becausetheoutlookbelongstoeveryonetheproblemdoes,too.Thereisreal,notjustapparent,strifebetweentheontologyofreductionisticatomism,whichtellsusthatthepiecesthatcomposetheobjectsofordinaryexperiencearetheonlyeffectivecausalagents,andourdeeplyrooted

intuitionthatweourselves,thoughmaterial,physicalbeings,areaspersonsbothcausalandmoralagents.Wehavereal,notmock,warfareonourhands.Theserivalclaimscannotbeexplainedaway;theymustbeadjudicated,notignored.

AtomisticStrategies

IhavebeenabletofindnosupportinRyle'sownexamplesorinmyattemptstofollowhishintsforthethesisthat,becauseofthetechnicalnatureofthescientificenterprise,whatsciencetellsusabouttheworldisnotadescriptionandsocouldnotconflictwithourcommonsenseintuitionsanddescriptionsoftheworld.Ibelievethatthesistobemistaken.Nevertheless,Ryle'sexamplesandanalogiesraiseotherquestions,whichIhavenotyetaddressed.Clearly,thelanguageweemployinordinaryaffairsismarvelouslysubtleandcomplex.Sovariedareourmodesofupper-levelspeechthatreductionismfacesaformidabletask;thesimplesubstitutionofatomisticnounsandverbsforthetermsofcommonspeechisbutapartofwhatneedstobedone.Indeed,theantireductionisticargumentstowhichIshallturninthefollowingchaptersclaimtoshowthattherearesomevalidandwidelyusedformsofupper-levellanguagethatcannotbereduced.Letme,then,concludethischapterandprepareforthenextbysettingforth,moresystematicallythanIhavedonehitherto,how,accordingtothereductionistprogram,thevariouspatternsofupper-levelspeecharetobebroughtintoastandardatomistformat.

Thedescriptionsweproduceinordinaryconversationandintheupper-levelsciencesdisplayseveralfeatures,eachofwhichpresentsitsownchallengetothereductionistprogram.Iamabletodistinguishfivesuchfeatures:First,wesometimesrefertoupper-levelentitiesbytheirpropernames.Second,inreferringtoupper-levelthingsasinstancesofkinds,wesometimescharacterizethembyintrinsic

properties.Third,someupper-levelkindsarecharacterizedbyrelationalproperties.Fourth,someofthepropertiesweassigntoupper-levelentitiesarepropensities,orabilities.Fifth,someoftheseabilitiesareabilitiestoproducesubjectiveexperiences.Letusconsiderhowtheatomistprogrammeets,orisintendedtomeet,eachofthesechallenges.

ProperNames.

Consider,first,thesimplestofthesetypesofupper-levelnarration.Whateverotherfeaturesmaybepresent,upper-levelandcommonsensetalkdoespickoutentities,actions,andcircumstancesforwhichtherearenolower-levelnames.Supposetheupper-levelreferenceoccursbymeansofapropername.Insuchacase,toreplacetheconventionalupper-leveldesignationforacompositeobjectorprocessbyanatomicspecificationforexample,toreplace"thatobject"(pointingtoacrystalofsalt)by"thosesodiumandchlorideionsarrangedincubicarray,"andsoonistoconveyalltheinformationoftheupper-levelformulationandmore.Thereisnolossbutratheragainwhenthespelling-outofthecompositionandstructureofanobjectissubstitutedforitspropername.Initselfthatis,apartfromitsabilities,itsrelationstootherthings,andtoourexperiencesofitanyindividualcompositeobjectjustisitsparts,arrangedastheyareanddoingwhattheydo;nothingmore.

IntrinsicProperties.

Second,whenwepickoutanordinaryentityasaninstanceofakindwhosecharacterizingpropertyisintrinsictotheentity,aswhenwerefertotheobjectasasaltcrystal,then,too,explicationoftheupper-leveltermbymeansofthestructuralfeaturesandinternaldynamicsoftheupper-levelentityleadstoagainofinformation,notaloss.Intrinsicproperties,atleastaccordingtotheatomistprogram,canalwaysbegivenalower-level,structuralexplication.Thus,saltcrystalsarecharacterizedmicroscopicallyascubicarraysofsodiumandchlorideions;galaxiesarecollectionsofenormousnumbersofstars,protostars,planets,gases,dust,andotherdebris;anddeuteriumnucleiareneutron-protonpairstightlyboundbythenuclearforce.

Now,whenwereplaceacommonsensedescriptionorformulationbyitstranslationintothelanguageoftheparts,wemustreplacethe

commonsensetermsforkindsbythelower-levelexplicationsofthosekinds.Assuredly,somethingmaybelostinthistranslation.Whatmayvanishisthesetofimplicationsandreferencestootherpiecesoftheworld(whenthekindsarespecifiedintermsofrelationalproperties)andtooursubjectiveexperiences.Butifouraimistodescribetruly,accurately,andexactlyalimitedsectionoftheworldasitisinitself,andonlythatsec-

tion,thenweneednotrefertootherpartsoftheworldandtooursubjectiveexperiences,fortheyarenotpartoftheintrinsicsituation.Still,thereareotherfactsthatmustbeincludedinacompletedescriptionofthewholeofreality,amongthemthetruthsweexpressinrelationaltermsandintermsofoursubjectiveexperiences.

RelationalProperties.

Whenwedescribeanyobjectorspatiotemporalportionoftheworldaccordingtothestandardformatofreductionisticatomismweleaveoutthoseassertionsabouttheobjectorpieceoftheworldthatrefertorelationsbetweenitandotherthings.Whatmustbedonewiththisleftovercontentoftheupper-leveldescriptions?Arelationalpropertyofanobject(thatis,apropertynotintrinsictotheobjectandsonotexplicableintermsofitsstructure)isshowntobeanintrinsic,structuralpropertyofalargersystemthatincludestheobject.Thistreatmentofrelationalpropertiesisnotatechnicalpeculiarityofthereductionisticprogram;itfitsequallycomfortablywithinthepurviewofcommonsense,asthefollowingexamplesshow.Detroit'shavingapopulationinexcessofonemillionisapropertydiscoverablebyonewhoseattentionisconcentratedwhollyuponthecityitself,butDetroit'sbeingnorthofTampa,arelationalpropertyofDetroit,issimplyastructuralproperty,havingtodowiththearrangementoftheparts,ofalargersystemofwhichbothDetroitandTampaarecomponents.WhileengagedinactionoffthecoastofBrittany,HoratioHornblowerbecameafather;buteventhoseofhiscompanionswhowereregardinghimmostcloselyatthetimefailedtonoticetheevent.WhatweactuallyrefertointhisapparentdescriptionofHornbloweristhebirthofachildtoawomaninEnglandandtheprevioussigningofamarriagecontractbythatwomanandHornblower.Werefer,thatis,toanetworkofcausal(andperhapsother)connectionsinalargersystemofwhichHornblowerisapart.

Butnoticethat,althoughinthesecasesassigningarelationalpropertytoanobjectisequivalenttoassigningastructuralpropertytoalargersystem,theequivalenceinvolvesnoshifttoalowerlevelofdescription.Thisobservationsuggestswhatappearstobeapromisinglead.Unlikedescriptionsofobjectsintermsofintrinsicproperties,whichplacethediscourseona

lowerlevelwherethepartsdothecausalaction,descriptionsintermsofrelationalpropertiesseemtoretaintheoriginallevelofdescription,merelybroadeningthescopeofthediscourse.Theyrequireustoaddtothecastofcharacterswithoutdismissinganyofthem.Thetendencyofthisobservation,thoughnotexplicitlyantireductionistic,isatleastnotexplicitlyreductionistic.Itisreasonabletosuppose,therefore,thatsomeofthelawsoftheupper-levelsciences,statedintermsofrelationalproperties,mayresistreductioninthismanner.ArgumentstothiseffecthavebeenproposedbyMichaelPolanyi,KarlPopper,andJerryFodor.Becausethesesuggestionsrepresentadeparturefromstandardreductionistdoctrine,Ishallpostponeadetaileddiscussionofthemuntilchapter7.

Abilities.

Bothinupper-levelsciencesandinourordinarytalkabouttheworldwemakefreeuseofamodeofdescriptionthatincludesreferencetotheabilitiesofupper-levelentitiestoactincertainwaysand/ortoproducecertaineffects.Forexample,inascribingthepropertyshininesstoabarofsteelwerefertoitsabilitytoreflectincidentvisiblelightwithoutappreciablescattering.Thedescription"Xisshiny"isequivalentto"Xisabletoreflectlightlikeamirror."Asecondexampleofacommonsensepropertythatturnsouttobeapropensityisthecommonsensemeaningof"warmth.''Thedescription"Xiswarm"isequivalentto"Xisabletoinducewarmth-sensationsinanormal,suitablypreparedhuman.''

Asprescribedbytheatomistprogram,anyabilitymustbeexplicatedintermsofthecompositionandstructureoftheobjectthathasitandintermsofthegenerallawsthatgovernthebehavioroftheobject'sparts.Toseethatthisprescriptionisreasonableandinaccordwithcommonsense,considerthefollowingcharacteristicsofthewayweordinarilyascribeabilitiestoeverydayobjects.

Note,first,thatabilitiesareintrinsictotheobjectsthathavethem,becauseanabilityisdistinctfromthetestsbywhichwedetectit.TheabilityofXtodoYincircumstancesCcanbedetectedbyarrangingthecircumstancessothatXactuallydoesY.Buttheabilitytodosomethingisnotidenticaltothedoing.Forexample,itwouldnotbeincoherenttosuggestthatacertainbarofsteelisshiny,thoughitbeforged,polished,andmelteddown

againindarkness.Theabilitytoreflectvisiblelightlikeamirrordoesnotdependontheactualpresenceofvisiblelight.Warmth,too,isanintrinsicproperty.SupposeItouchanobjectontwooccasionsfiveminutesapartandfindittobewarmbothtimes.Icanthenassert,possiblyincorrectlybutnotincoherently,thatitiswarmalsoduringthefive-minuteinterval.Imayevenassert,againnotincoherently,thatanotherobjectiswarmeventhoughnoonehaseverfeltit,evenifithasnevertouchedanotherobject.Callingitwarmisequivalenttoclaimingthatifithadbeentoucheditwouldhaveproducedasensationofwarmth.Similarcounterfactualstatementscanbeextractedfromthepropertyshininess.Theconnectionbetweenabilitiesandcounterfactualsisacluethatabilitydescriptionscanbetranslatedintolawlike,causaldescriptions.

Asecondfeatureofabilitiesisthattheyareopen-ended.Warmthistheabilitytoproducewarmth-sensationsinanindefinitenumberofhumanbeingsandinanindefinitenumberofcircumstances;butitis(orislawfullytiedto)theabilitytodomanyotherthingsaswell:tocausethermometers(ofanindefinitevarietyofdesigns)torespondincertainways,totransferheattocoolerobjects,andsoon.

Abilitiesareintrinsictotheobjectsthathavethem,buthavingacertainstructureisalsoanintrinsicpropertyofacompositething.Moreover(andstillwithinthedomainofcommonsense),theabilitiesofthingsarefrequentlylinkedtotheirstructures.Considertheabilityofarattlesnaketostrike.Inonesenseof"abletostrike,"everynormal,healthyrattlerisabletostrike;yet,inanothersense,onlyarattlerthatiscoiledinacertainwayisabletostrike.Arattlesnakehastheability(inthesecondofthesetwosenses)byvirtueofitsbeingcoiled.Wesaythatthestructuralproperty(beingcoiled)accountsfortheability;therattler'sstructureenablesittostrikeorgivesittheabilitytostrike.Yet,suchareourlinguistichabits,weresistsayingthattheabilitytostrikeinthesecondsenseisidenticaltobeingcoiled.

Now,theremaybegoodreasonsforourhabitsinthiscase.Theactionthatanobjectisabletodobyvirtueofitsstructureisrelatedtothatstructuresomewhataseffectistocause,oratleastaseffectistocausallyantecedentconditions.Andapervasivefeatureofcausationisthenonspecificityofeffecttocause;generally,agiveneffectcanbeproducedbyavarietyofcauses.Perhaps

becauseofthisasymmetrybetweencausesandtheireffectswefindasimilarasymmetryinourlinguistichabits:Wearewillingtosaythattobecoiled3istobeabletostrikebutunwillingtosaythattobeabletostrikeistobecoiled.Itmaybethatnorattlerhaseverstruckfromanuncoiledposition,yetwefeelthatunusualcircumstancesmightarisesuchthatanuncoiledrattlerwouldbeabletostrikeforexample,itmightbesupportedinsomemechanicalcontrivanceorwedgedbetweentwostones.

Finally,causesoccurintransitivesequences.Thisfeatureoftheworld,too,hasitscounterpartinourspeakingaboutstructuresandabilities.Anormal,healthyrattlesnakeisabletocoilitselfbyvirtueofitsmuscularandskeletalstructure.Therefore,wesaythattohavethenormalrattlesnakestructureistobeabletocoilup.Buttobeabletocoilupistobeabletoplaceitselfinapositiontostrike.Therefore,tohavethenormalstructureistobeabletostrike.Sothedifferencebetweenthetwosensesof"abletostrike,"notedabove,isamatterofproximityinthecausalchain.

Soweseethattalkingaboutabilitiesandtalkingaboutstructuresthatconferthoseabilitiesarebothnormalfeaturesofourcommonsenseformulationsofthewaythingsare.Therefore,thegoalofreductionisticsciencetoaccountforallthepropensitiesoftheobjectsofeverydayexperienceintermsoftheirstructuralfeaturesandthepropensitiesoftheirpartsisnotforeigntoourordinarywayofdealingwiththeworld.

Butcanwe,merelybyspellingoutthecomposition,structure,andlawsofbehaviorofthepartsofcompositesystems,sayatalowerlevelallthatwesayatanupperlevelintermsofabilities?Wehaveseenthat,ingeneral,theabilitytodosomethingisnotstrictlyidentifiedwiththeobject'sstructure.Nevertheless,wedohabituallyidentifyabilitieswithstructuresundernormalcircumstances.We

naturallysay,speakingofrattlesnakesingeneral,thatforthemtobeabletostrikeistohavethenormalrattlesnakestructure.Thegeneralizationswemakeaboutrattlesnakesandtheircharacteristicabilitiesaremadewiththeunderstandingthatnormalcircumstancesprevail.Awoundedsnakemightbegiventheabilitytostrikebysomeprostheticdevice,butwhenwe

3/Ofcourse,otherconditionsmustbeadded,suchasbeingalive,awake,healthy,etc.Theseareomittedhereforthesakeofbrevity.

speakingeneraltermsofstrikingabilityinsnakeswetacitlyruleoutsuchartificialcircumstances.

Thispointisevenmoreobviousinthecaseofwarmth.Theabilitytoinducewarmth-sensations(nomatterhow)cannotbeidenticaltothermodynamicorstatistical-mechanicaltemperature,for,ifwearewillingtoconsidernonstandardcircumstancessuchasunusualstatesofthehumanperceiver,thenobjectsinidenticalintrinsicstatesmaybewarmonsomeoccasionsandnotwarmonothers.Butwenormallydeterminethatwarmthshallbeanintrinsic,public,objectivepropertyofobjects,andwecarryoutthisresolutionbysettingupstandardconditionsunderwhichthepropensityistobedisplayed.Soresolved,wesaythat,understandardconditions,tohavethestatistical-mechanicalpropertyistobeabletoinducewarmth-sensationsandtobeabletoinducewarmth-sensationsistohavethestatisticalproperty.Giventhelawsofphysicsandthestandardconditions,agivenobjectinduceswarmth-sensationsifandonlyifithasthatstatisticalproperty.Thesestandardconditionsincludethestateoftheperceiver,themodeofconnectionbetweenperceiverandobject,andthemannerofpreparationoftheobject.

Itmaybethat,inspeakingoftechnicalandsemitechnicalconcepts,Ryleisreferring,amongotherexamples,tothesortofstandardizationIhaveoutlinedforwarmth.Inthatprocess,standardconditionsarespecifiedsothatouruseof"warmth"canbeobjective,sothatindescribinganobjectaswarmwecancutourascriptionloosefrom"thefactsofhumanandanimalphysiologyandthefactsofhumanandanimalpsychology."Butissucharefinedconceptreallytechnicalorsemitechnical?Eveninordinaryspeechweintendwarmthtobeanintrinsicproperty.Therefore,whenaphysicistorotherspecialistdoesmaketheefforttostandardizethermometry,sheisnotturningacommonsenseconceptintoatechnicalorsemitechnicalonenot,forexample,givingapeculiartwistorspecialmeaningtotheconceptbut

merelyfulfillinganobligationthatbindseveryuseroflanguage.Inthislaborthephysicistworksonbehalfofeveryone.

Tosummarize:Wheninupper-levelspeechweascribeanabilitytoanobject,wemeanthatitisabletoperformaspecifiedactionorproduceaspecifiedeffect(andpossiblyweaddadescriptionofthecircumstancesunderwhichthisabilityisdemonstrated).Thelower-leveltranslationofthisability-ascriptioncon-

sistsofaspelling-outofthecompositionandstructureoftheobject,alower-levelexplicationoftheactionoreffect,andanexpositionofthelawsofbehaviorofthepartsintermsofwhichtheselower-levelexplicationshavebeenformulated.Fromthisinformationonecanobtain,bythestandardtheoreticalmethodsofthelower-levelscience,astatementthattheactionoccursorthattheeffectisproducedundersomespecifiablecircumstances.Andwhenweshowthattherearenomologicallypossiblecircumstancesunderwhichanobjectperformsacertainaction,wehavecapturedallthatwemeantoconveywhenwesayitisabletoperformthataction.

SubjectiveExperiences.

Finally,letusconsiderthemostrecalcitrantsortofcommonsenselocution:descriptionsformulatedintermsofabilitiestoinduceexperiencesinhumanperceivers,as,forexample,"lookingblue,"or"beingpainfullyhot."Thestandardresponsetothischallengeproceedsbytwostages.First,wearguethatthefactthatastateofaffairsobtaininginaportionoftheworldoutthere,thatis,inabitoftheworldthatdoesnotincludeahumanobserver,isabletoproduce,underappropriateadditionalcircumstances,certainresultsintheperceiverisnothingtotheobjectorstateofaffairsinitself.Therefore,theabsenceofreferencetopotentialhumanexperiencesintheatomistdescriptionoftheobjectorstateofaffairsdoesnotconstituteafault,for,thoughthosepotentialexperiencesareoftremendousimportancetothehumanperceiver,theyarenotalegitimatepartofanobjectivedescriptionofthatexternalthing.

Nevertheless,thosereferencestoobjectiveexperiencesarepresumablytrueandbelongsomewhereinacompletedescriptionofwhatthereis.Therefore,acompletedescriptionoftheworld(notjustadescriptionofthenonhumanportionsofit)mustsomehowfindawayofcomingtotermswiththoseexperiences.Thisbringsustothe

secondstageofthestandardresponsetothechallenge.Abilitiestoaffectorproducehumanconsciousexperiencesaretreatedinthesamemannerasabilitiestoaffectother,nonsentientobjects,asoutlinedaboveforthetreatmentofpropensitiesingeneral.Abilitiestoaffectconsciousnessareexplicatednotasintrinsicpropertiesoftheobjectsthathavethembutaslawlikegeneralizationsaboutthecomposition,structure,

andinternalprocessesofportionsoftheworldthatincludeperceivers.

Butonthisfronttheprogramhasnotprogressedveryfar,forwhenthestandardtreatmentofpropensitystatementsisappliedtoabilitiestoproducesubjectiveexperienceswefindthatweneedalower-levelexplicationofwhatitistocauseasubjectiveexperience,andatleastatthemomentweareunabletoproducelower-levelexplicationsofwhatanindividualsubjectiveexperienceis.Wecomefacetoface,inshort,withthemind-bodyproblem.Atthisjuncturereductionistshaveproposedavarietyofscenariosforthefuturedevelopmentoftheprogramofreduction,allofthemgoingundertheheadingofphysicalism.Ifatomisticreductionistosucceed,somethingalongthelinesofthephysicalisttheoryofmindmustultimatelycarrytheday.Ishallreturntothatportionoftheatomistprograminchapter8.

FourTeleology:ReducingCyberneticsWhatfeaturesdistinguishlivingorganismsfromallotherthings?Canthedistinctionbeexpressedinpurelymechanisticterms,ordoesitresistareductiveanalysis?Hintstowardanswerstothesequestionsmaybegleanedfromthefactthatanorganismissomethingtowhichteleologicalconceptsapply.Livingthingstypically,humanbeingsharborintentions,seekgoals,andadaptmeanstoendswithconsciousdeliberation.Theseactivitiesareparadigmsofteleology.Butwealsofinditappropriatetoapplysuchteleologicalconceptsasfunctionandadaptationtoorganismsassimpleasplants.Clearly,then,functionalityamongthepartsofanorganismdoesnotentailconsciousnessinthewhole.Norneedtalkoffunctionsimplyanythingproorconaboutanorganism'shavingbeenproducedbyadivineDesigner.Thatmuchisevidentfromthewaynaturaltheologywasdoneinpre-Darwiniantimes.Theproponentsoftheargumentfromdesigndrewtheirtheologicalconclusionfromtheirobservationsoftheadaptednessoforganisms.Becausetheadaptednessisdiscernibleindependentlyoftheologicalconsid-

erations,itislogicallypriortothem.Andbiologiststodayspeaknontheologicallyoftheadaptationsoforganismstotheirenvironment,andsomeevendebatewhetherthe"ultimategoal"ofnaturalselectionistheproliferationofgenesorsomeother,higher-levelresult.Clearly,evenaverysimpleorganismmayseekgoalsofitsown,itspartsmayhavefunctionsandserveends,anditmayadaptitselftothreateningorchallengingcircumstances.Teleologicalactivitiessuchasthesecanberecognizedforwhattheyarepurelybyreferencetotheorganism'sowninternalstructureandtoitsinteractionswiththeenvironment.Anorganismisateleologicalthing,simplyonitsowntermsandapartfromanypossiblerelationtoconsciousnessortointelligentdesign.

Naturalobjects,then,fallintotwocategories,oneoflivingthingsandhumanartifacts,whichhaveteleologicalfeatures,andanotherofthenonartifactualinorganic,whichdonot.Thequestionarises,therefore,whethertheorganicsciencesaredividedfromtheinorganicbyanunbridgeablegulf,sothatlivingcreaturesshouldrateaseparateandirreducibleentryinourcatalogofnaturalobjects.Isalivingthingmerelyanunusuallycomplicateddynamicalarrangementofparts,astheatomistprogramsuggests,ordoesitdisplayanutterlynovelfeature?Aregoals,functions,purposes,andthelikemerelyinterestingexamplesofwhatatomscandoandhowtheycanarrangethemselveswhentheyfalltogetherinsufficientlylargenumbers,oraretheyirreduciblecharacteristicsoflife,symptomsofadeepdichotomyinnatureandguarantorsoftheultimateautonomyoftheorganicsciences?

Thesearebroadbutalsovaguequeries.Wecantakeafewstepstowardansweringthembyposinganarrower,moreclearlydefinedquestion:Cansometypicalteleologicalconceptsbereducedtostandardmechanicalconcepts?Canweunderstandfunctions,goals,andadaptationsincomplexorganismssimplyintermsofthearrangementsandinteractionsoftheiratomicparts?

APeculiarKindofReduction

Clearly,thequestionwehaveposedconcernsthereductionofupper-levellanguagestoalowerlevel;itlacks,however,someofthefeatureswefindintheparadigmsofinterlevelreduction

oftheories.Inthestandardcases,onestartswithtwotheoriesthatapplytothesamesetofobjectsbutoperateatdifferentlevelsofanalysis.Thesetheoriesaresufficientlycompletetobeformulatedasaxiomatizedlogicalstructures,sothattheycanserveassourcesofdeductive-nomologicalexplanations.Thequestionofinterlevelreductioncanthenbephrasedinthismanner:Cantheaxiomsandtheoriesoftheupperlevelbededuced,withtheaidofbridgingpostulates,fromtheaxiomsofthelower-leveltheory?Theprimaryexampleofthiskindofreductionisthederivationofmacroscopicthermodynamicsfromthestatisticalmechanicsofcollectionsoflargenumbersofatoms.Thereductionestablishesconnectionsbetweenupper-levelandlower-levelconcepts.Entropy,heat,andtemperature,forexample,acquireexplicationsintermsofthestatisticalpropertiesofswarmsofmicroscopicbodies.Thisexplicationofupper-levelconceptsintermsoflower-levelonesproceedshand-in-handwiththederivationofupper-leveltheoriesfromtheoriesthatoperateatlowerlevels.Thecoherenceoftheentireprocessvalidatesboththederivationandtheexplication.Whetherthetemperatureofagasmustbeunderstoodastheaveragekineticenergyofitsmoleculesorassomemoresubtlestatisticalpropertyofthepartsdependsonwhethersuchanunderstandingallowsustoderivefromthelower-leveltheoryallthatmustbesaidaboutmacroscopicobjectsinupper-levellanguage.

Paralleltothisdevelopmentinthermodynamicsrunattemptstoreduceportionsofbiologytotheprinciplesofphysicsandchemistry.WhentheeffortsofMaryB.Williams(1970;1973)toconstructanaxiomsetforevolutiontheorygaingeneralacceptance,andwhenandifsuccessfulderivationsoftheseaxiomsfromthelawsofmolecularbiologyareproduced,thenwemayexpectanalysesoftheconceptsofadaptationandfunctiontoparticipateintheprocessaslinksbetweenlowerandupperlevels.Butweneednotwaitfortheaxiomatizersof

upper-leveltheoriestocompletetheirtasksbeforeweaskwhetherteleologicalconceptsarereducibletomechanisticones.Eventhough,strictlyspeaking,theissuewillnotbesettleduntilthelogicalstructuresofthetwolevelsofdiscoursehavebeenformallydisplayedonceandforall,thedebateovertheexplicationandpossiblereductionofteleologyhasproducedanumberofcogentargumentsbothproandcon.Thereareplentyofinformalbutsufficiently

clearusesofteleologicalconceptsbothinordinaryspeechandintheorganicsciences.Wemaybesatisfiedatpresent,therefore,withaninformalreductionanditsconcomitantexplicationofteleologicalconcepts.Suchareductiveexplication,providedwecanconstructone,wouldbeallthatweneedasweattempttodecidewhetheronecanplausiblyaffirmorreasonablydoubtthatalivingthingisanythingoverandaboveacollectionofmechanicallyinteractingatomicparts.

AttemptstogeneratereductiveexplicationsofteleologicalconceptsdeservetostandalongsidethemicroreductionofthermodynamicsandthestilldebatedreductionofMendeliantomoleculargeneticsasvalidadditionstoourstockofexamplesofinterlevelreduction.Thequestionweshallfaceinthischapterdoesnotdirectlyconcernthederivationofonewell-formulatedtheoreticalstructurefromanother;rather,itconcernstheexplicationofasetofsomewhatmurkyupper-levelconceptsintermsofclearerconceptsthatoperateatalowerlevelofdiscourse.Wecannotmeasurethesuccessoftheenterpriseagainstastableandformalupper-leveltheory;rather,wemustaskwhetheraproposedexplicationsquareswiththeintuitionsdevelopedthroughusingtheupper-levelconceptsininformaldescriptionsandexplanations.Intuitionsaretosomeextentmalleable,subjecttomodificationandgrowth.Wemayexpect,therefore,thatourattempttoexplicateteleologicalconceptsintermsofmechanisticoneswillclarifytheupper-levelconceptsandsharpendistinctions.Iftheeffortsucceeds,wewilldiscoverwhatweoughttohavemeantallalongbyfunction,goal,adaptation,andtheirkin.

Philosophicalanalysesofteleologydifferastothedegreetowhichtheyconcentrateuponbiology.Some,ofwhichtheworksofBerentEnc(1979),PeterAchinstein(1977),ChristopherBoorse(1976),AndrewWoodfield(1976),andLarryWright(1973;1976)arerecentexamples,aimatthegreatestpossiblegenerality,assigningaprominentplacetothewayweuseteleologicaltermsindescribingthe

activitiesofhumanbeings,incontextswherethereisapresumptionofconsciousintentionordesign.Theseanalysestreattheuseofteleologicaltermswhereconsciousnessisnotimplicatedasaspecialcase.Subhumanbiologyprovidesrestrictedexamplesatbest;andinWoodward'sanalysisnonconsciousteleologyturnsouttobedefectiveormerelyanalogical.Theotherapproachtotheanalyticaltask,of

whichErnestNagel's(1977),WilliamWimsatt's(1971),andFranciscoAyala's(1970)inotherrespectsverydifferentanalysesarerecentexamples,concentratesonbiology.Withoutdisavowinganinterestintheanalysisofteleologyingeneral,thisapproachdrawsitsparadigmsfromfunctiontalkasitappliestothepartsofsimplelivingsystems.Ishalladoptthemorerestrictedofthesetwoapproaches,proceedingfromparticularcasesinnonconscioussystemsonlyasteportwointhedirectionofgenerality,fortworeasons.First,althoughbyfocusinginitiallyuponfunctionsinordinarybiologywepostponeageneralunderstandingofallusesofteleologicalconcepts,wegaintherebyagreaterappreciationofthecomplexityanddiversityofuseswithinbiologyitself.Second,wewouldviolatethespiritoftheatomistreductionprogramifwetooktheanalysisofteleologyinmentalistictermsasaparadigm.Accordingtothisprogram,talkofpurposes,goalsandfunctionsinhumanaffairsmustbeunderstoodintermsoftheteleologyofnonconscioussystems;mentalisticconceptsmustbereducibletomerelymechanisticterms,notthereverse.Thatreductionmayturnouttobeimpossible,butwemustnotprejudgetheissue.Bytakingtheinductiveapproach,proceedingfromfunctiontalkinsimpleorganismsandinmachinestowardtheanalysisofteleologyinconsciousbeings,wecangivetheatomistprogramafairhearing,allowingittodemonstrateitsfullstrength.

Havingchosenthissecondapproach,wefaceanotherpairofalternatives,oneseemingtofavorthereductionistconjecture,theothertheantireductionist.Theolderalternative,proposedoriginallybyArturoRosenblueth,NorbertWiener,andJulianBigelow(1943),analyzesteleologyinlivingthingsandhumanartifactsintermsoftheconceptsofcybernetics.Accordingtotheirconjecture,whichhasbeendevelopedandrefinedbymanyauthors,whenweascribeafunctiontoapartofanorganismormachineweclaimthatthecontainingsystemisorganizedaccordingtoacyberneticpattern,

typicallyfeedback;thatbeingsoorganizeditseeksagoal;andthatthepartinquestioncontributesinsomewaytowardtheachievingofthatgoal.Thiscontributionisitsfunction.Amorerecentconjecturehasbeenproposed,withvariations,byWilliamC.Wimsatt(1972)andbyLarryWright(1973;1976).Whereasthecyberneticanalysistakeshumangoalseekingandbiologicalhomeostasisaspara-

digmatic,thenewerconjecture,whichIshallcalltheselectionistanalysis,drawsitsparadigmsfromhumancreativeactivityandfromthetheoryofnaturalselection.Accordingtotheselectionisttheory,whenweascribeafunctiontoapartofanorganismormachine,wecallattentiontotheprocessbywhichthesystemcametobeasitis,withthatpartinitspresentplace;wealsoclaimthattheprocessinvolvedaweeding-outorselectionandthatthepartcontributedinsomewaytowardthesystem'ssurvivingtheselectionprocess.Thiscontributionisthepart'sfunction.

Theserivalanalysesofteleologysuggestatleastprimafaciecasesforandagainstthereductionistprogram.Proponentsofthecybernetictraditionanalyzegoalorientationandfunctionalityintermsofthearrangementsanddispositionsofanorganism'sparts.Thethrustofthisapproachmovesinwardanddownwardtothepartscontainedinthegoal-seekingsystem,andsotolowerlevelsoforganization.Althoughthecasemuststillbearguedindetail,thereisreasontosupposethatthecybernetictheoryofteleologywillpermitustoconstructareductiveexplication.Thatreductionwouldbefar-reachingindeed,forWilliamT.Powers(1973;1978)hasshownushowtosubjectevenhumanbehaviortoacyberneticanalysis.Theselectionisttheory,ontheotherhand,pointstoselectivesystemsandotherprocessesthatenclosetheteleologicalsystemand,forthatreason,perhapspointsalsoupwardtohigherlevelsoforganization.Again,thecasemustbeexaminedindetail,andIattempttodosoinchapter6;nevertheless,wemayreasonablysupposethat,iffunctionalityinbiologycanbeunderstoodonlyintermsofselectionprocessesandthesystemsthatsupportthem,ourexplicationofteleologywillconveyanon-orevenantireductiveflavor.

Therivalrybetweenvariousanalysesofbiologicalexamplesofteleologyhassparkedavigorousdebate,whichIshallreviewbelow.AlthoughErnestNagel(1977)hasdefendedhisversionofthe

cybernetictheoryagainstvariouscriticisms,includingWright'sandWoodfield's,LowellNissen(1981)raisesadditionalquestions,whichIshallexamine.ButperhapsthemostpersistentimpedimenttothecyberneticalreductionofteleologymaybetheonepointedoutbyWimsatt(1971).Untilwehaveproducedaconvincingreductionofatypicalcyberneticconceptsuchasfeedback,wecannotplacemuchconfidenceinthereductiveclaimsofcyberneticism.Andfeedbackhasturnedouttobesurprisinglydifficulttoexplicate.(SeealsoManier1971.)

Cyberneticism

Itisnecessary,then,thatIattempttoestablishthecybernetictheoryasathoroughlyreductivealternativetotheselectionistaccount.Thatwoulddemonstratethepertinenceoftheirrivalrytoquestionsabouttheontologicalreductionoflivingthings.IdosobyproposingananalysisoftheconceptoffeedbackthatextendstheexplicationsofNagel(1961;1977)andBeckner(1959;1968;1969)andshowingthattheunderstandingsoachievedcanbeputtogooduseintheatomistreductionprogram.Havingestablishedthereductionistcredentialsofthecyberneticalanalysis,Ishall,inthefollowingtwochapters,attempttojudgebetweenitanditsselectionistrival,concludingthatcybernetics,andnotselection,canhelpustoclarifyandjustifytheonlyscientificallyimportantsenseinwhichbiologistsemployteleologicalterms.

StagesInTheProgram.

Brieflystated,thereductionstrategyofthecybernetictheoryofteleologycallsforthefollowingfour-stepprogram.(1)Thetheoryassertsthatanorganismorothersystemisorientedtowardagoalstatejustifthepartsaresoarrangedthatundercertaincircumstancesitwouldactinawaythattendstomakethegoalstateoccurormorenearlyoccur.Withinlimits,thesystem'sinternalstatedisposesittomeetdeviationfromthegoalbyemployingappropriatecountermeasures.Thesystemmaybesosimplethatitsrepertoireincludesjustonestrategy,oritmaybesocomplexthatitcanshifttoamoreeffectiveoneasconditionschange.(2)Thecybernetictheoryclaimsthatthetypeoforganizationknownasnegativefeedbackistheprimeexampleofsuchaninternalstate.Inatemperature-controlledhouse,forexample,thefurnaceturnsonoroffasthetemperaturefallsbeloworrisesaboveacertainaimed-atrange.Inthebodiesofmammals,totakeonemoreexample,bloodvesselsconstrictordilate

andshiveringbeginsorceasesasthetemperatureofthebloodfallsorrisesbeyondtheorganism'snormaltemperature.Somespecialhookupofwiresandswitchesorchestratesthefurnace'sbenigninfluenceonthetemperatureoftheroom,andasetofspecialanatomicalpartsperformsasimilargoverningactivityinthemammal'sinternaleconomy.Theseregulatingmechanisms,whetherhumanartifactsorphysiologicalhomeostats,arefeedbackdevices.(3)Inacyberneticreduction

wemustspecifyexplicitlywhatkindofassemblageofpartswhatcharacteristicwiringdiagramqualifiesasystemasanegativefeedbackdevice.Doingthisamountstoreducingapropertyofanentiresystemtorelationalanddispositionalpropertiesofitsparts.(4)Wemustshowhowthischaracterizationcanbereducedinitsturntostilllowerlevelsofdescription,eventuallytotheleveloffundamentalparticles.Steps3and4willoccupyourattentionintheremainderofthischapter;theplausibilityofsteps1and2willbecomeapparentaswesubsequentlyexaminethebiologicalemploymentofcyberneticconceptsinteleologicalexplanations.

ObjectsAndTheories.

Letusthentakeupthetaskofexplicatingtheconceptofnegativefeedbackintermsofthearrangementandinteractionsofasystem'sparts.Herewemustmakeachoiceastomethod.Theobviousandstraightforwardwaytoexpresstheexplicationwerequireistosayhowthesystemdoesorwouldbehaveandhowitspartsinteractingeneratingthisbehaviorormakingitpossible.Thisanalysisspeaksdirectlyaboutthesystemitselfandabouttheobjectsthatcomposeit.Ishallcallthisanobject-referringexplication.Butanother,moreelaboratewayofformulatingtheexplicationhasalsobeenadoptedbythosewhoanalyzecyberneticconcepts,oftenwithoutclearlydistinguishingitfromthefirst.Theseexplicationsoffeedbackareformulatedintermsofthedescriptionsoneappliestocandidatesystemsofmathematicalvariablesandthefunctionsthatrelatethem.Ishallcallthissecondsortofexplicationatheory-referringexplication.Theobject-referringsortofexplicationhasthemeritsofsimplicityanddirectness.Butthetheory-referringsortisalsoessentialtoourtaskfortworeasons:First,wecannotcharacterizeafeedbackdevicesimplyintermsofthebehavioritdisplaysduringafiniteperiodofobservation,becausesuchacriterionwouldnotdistinguishacleverorfortuitousimitationfromthegenuinearticle.Rather,wemustalso

specifywhatthesystemwoulddounderarangeofconditionsnotactuallyobserved.Wemust,therefore,speakofthedispositionsofthesystemanditsparts,oftheirlawfulbehaviorunderconditionscontrarytofactinshort,ofthelawsofnaturethatgoverntheiractivities.Althoughweintendourexplicationtoexpressthewaythingsareaccordingtothelawsofnature,forpracticalandepistemologicalreasonswemustformulateitintermsofour

bestcurrentscientifictheories.Second,tocompletethefourthstepinreducingteleology,wemustdemonstratehowtoobtainthedescriptivestatementthatasystemoperatesinthefeedbackmodefromstatementsthatdescribethearrangementsandinteractionsofitsparts.Inshort,wemustproduceatheory-referringexplication.

Feedback

Rosenblueth,Wiener,andBigelow'seffort(1943;1950)toexplicategoalorientationinpurelybehavioristictermswassoconvincinglycriticizedbyRichardTaylor(1950a;1950b)thatsubsequentinvestigatorswhohavenotsympathizedwithTaylor'spreferenceforamentalisticaccounthaveconcentratedonsearchingforananalysisintermsofinternalcausalmechanisms.Indeed,despitetheirannounceddeterminationtodistinguishteleologyfromcausality,evenRosenbluethandhiscolleaguesalludetocausalmechanismsintheiranalysisoffeedback,stipulatingthat''signalsfromthegoalareusedtorestrictoutputswhichwouldotherwisegobeyondthegoal''(1943,p.19).Others,suchasNagel(1961;1977),Manier(1971),andWimsatt(1971),havespokenofcausalmechanismsandofthemathematicalvariablesandfunctionsbywhichwerepresentthem.Themostambitiousandsystematiceffortofthissort,andtheoneonwhichIshallmodeltheanalysistobepresentedbelow,istheexplicationoftheconceptof"teleologicalsystem"proposedbyMortonBeckner(1959).

Ireferthereadertomyearlieressay(Faber1984)foramoredetaileddiscussionoftheproblemsofexplicatingfeedback.HereIshallsimplypresentasummaryofthatargument,inthreesteps.First,Ishallsetdowntheintuitivedesiderataofanexplicationoffeedback.Second,Ishallexpressmyanalysisoftheconceptinobject-referringterms.Finally,Ishallstatethesameexplicationmoreformallyintheory-referringterms.Asnotedabove,thislasteffortisrequiredif

wearetolearnwhethertheidentificationofasystemasafeedbackdevicecanbederivedfromitstheoreticaldescriptionatalowerlevelofanalysis.

InformalCharacterizationofFeedback.

Athermostatinahouseoranautomaticsteeringmechanisminasailboatperformsataskthatmighthavebeencarriedoutbythehouse-

holderorthesteersman.Thepossessorofoneofthesefeedbackdevicesregulatesthetemperatureoftheroomorthecourseoftheboatbyproxy.Thethermocouple,wires,andtransformerofthethermostat,orthevane,gears,andleversofthesteeringmechanismareadditionstothesystemtheycontrol.Theycouldberemovedentirelywithoutalteringthecausalconnectionsinthecontrollablesystem.Thetemperatureofthehousewouldstillbedeterminedbytheratesofinflowandoutflowofheat,andthecourseoftheboatwouldstillbedeterminedbytheangleofitsrudderandthepressureofwindandwavesoncanvasandhull.Inanyteleologicallyregulatedsystem,then,wemayexpecttofindadistinctsubassembly,theregulatingdevice,whichcanberemovedbybreakingcertaincausallinks.Infact,thethermostatsustainstwodistinctconnectionswiththeroom.Itsensesthecontrolledproperty,thetemperature,bymeansofathermocoupleorbimetallicstrip,whichissituatedinthermalcontactwiththeair,anditcontrolsorcorrectsthetemperature,turningthefurnaceonandoffbymeansofasetofwiresandrelayswitches.Extractingthethermocouplefromthedeviceorcuttingoneofthewiresleadingtothefurnacewillequallydisrupttheregulatingactivity.Eitherconnectionmaybebrokenwithoutaffectingtheother,andeachisnecessaryinthissensefortheproperoperationofthedevice.Sotheregulatingsubsystemsensesandcontrolsthroughtwophysicallydistinctcausalprocesses.Thesetwoconnectionsdifferalsowithrespecttodirection.Throughthesensinglinkcausalinfluencespassfromthelarger,controlledsystemtotheregulatingsubsystem,andthroughthecontrollinglinktheinfluencespassfromtheregulatorbacktothemainsystem.Justasthehouseholder'sshiveringorperspiringsignalsanexcessivevariationinthetemperatureoftheroomwithouttherebymateriallyinfluencingit,sothebimetallicstripexchangesafewcalorieswiththeroomwithoutintheprocessmateriallyaffectingitstemperature.Similarly,thefurnaceroarsintoflameasaresultofaswitchhavingbeenclosedbythetwistingofthe

bimetal,withouttherebyexertingadirectinfluenceonthelatter'sshape.Causalinfluencespasspredominantlyinjustonedirectionaroundthefeedbackloop.

Tosummarize:Wehavenotedthreedesiderataforasatisfactoryexplicationoffeedback.First,acompleteteleologicallycontrolledsystemmustexhibitasufficientdegreeofcomplexity,con-

sistingatleastofacontrolledsystemandaregulatingsubsystem.Second,thissubsystemmustbeconnectedtotheregulatedsystemthroughtwophysicallydistinctor"orthogonal"causalchannels.Third,theregulatormustpassivelysensethroughoneofthesechannelsandactivelycontrolthroughtheother.

Havingidentifiedcertaindesirablefeaturesofanadequateexplication,Inowsetdownmoreformally,andinobject-referringterms,asetofseverallynecessaryandjointlysufficientconditionsforamechanism'squalifyingasafeedbackdevice.Ipresentthisexplicationwithoutfurthersupportingarguments.Afullertreatmentoftheissueandacriticismofotherexplicationsmaybefoundinmy1984essay.FollowingthepresentationIshallillustrateitsimportbymeansofafewexamplesnotpreviouslypublished.

Object-ReferringExplicationofFeedback.

Acomplexsystemofcausallyinteractingpartsisafeedbacksystemifandonlyifthefollowingconditionsaresatisfied:(1)Thesystemconsistsoftwophysicallydistinctparts,acontrolledmainsystemandaregulator,bothofwhicharesubjecttocausalinfluencesfromanenvironment.(2)Thecontrolledsystemhasavariablepropertyg,whichdependscausallyonatleasttwoofitsothervariableproperties,f1andf2;andthesearecausallyindependentonefromtheother.Thatis,externalinfluencesmayalterf1andthroughitg,withoutmateriallyaffectingf2,andviceversa.(3)Theregulator'sconnectiontothecontrolledsystemproceedsthroughapairofdistinctcausalprocessestothepropertiesgandf1.Oneoftheseprocessesoperatesthroughatleastonecomponentpartwhoseremovalfromthesystemhastheeffectofdisruptingtheregulator'sinfluenceuponf1withoutmateriallyaffectingeitheritsrespondingtogorthecausaldependenceofguponf1andf2.Likewise,thereisatleastoneothercomponentpartwhoseexcisionfromthesystemrenderstheregulator

unresponsivetothepropertygwithoutmateriallyaffectingthedependenceofgonf1andf2.(4)Finally,thefeedbackmustbenegative;thatis,environmentallyinducedchangesinthepropertyf2mustresultinsmallervariationsinthepropertygwhenthestructureisintactthanwouldoccurifeitherofthesurgicaloperationsmentionedincondition3wereperformed.

Ourinterestinthereductionofteleologicaldescriptionsand

explanationsleadsustoaskformorethanthisobject-referringcriterion.Weneedtoknowwhetherastatementcharacterizingacompositeobjectasafeedbacksystemcanbederivedfromadescriptionthatcharacterizesthearrangementandinteractionsofthelower-levelobjectsthatcomposeit.Consequently,werequireasetofseverallynecessaryandjointlysufficientconditionsthatspelloutthecharacteristicfeaturesofthelower-leveldescriptionofateleologicalsystem;thatis,werequireanexplicationoffeedbackthatreferstotheoreticaldescriptions.Again,Ishallsimplypresenttheconclusionofmy1984argument;thereadermayrefertothatessayfordetails.

Theory-ReferringExplicationofFeedback

Letussupposethatwehavealower-leveldescriptionofacertaincandidatesystemandofrelevantportionsofitsenvironment.Thelevelmaybetheoneatwhichweemploytermsforbitsofwire,nuts,bolts,andbimetallicstrips;oritmaybeanystilllowerleveldowntoandincludingthatofsubatomicparticles.Atanylevelwehaveaconsistentsetofexplanatorylaws,oratleastrulesofthumb,forpredictingthebehaviorofthethingsnamedthereandfordescribingtheircausalinteractionsandspatialrelations.Theissuehereconcernsin-principlereduction;therefore,itisappropriatetoassumefurtherthatthelower-levelnarrativeisascompleteasdescriptionsatthatlevelcanbe.Ishallassumealower-leveldescriptionofthecompositesystemthatcontainsacompletelistofthethingsatthatlevelthatcomposethesystemanditsenvironment,anadequatesetofnaturallawsthatexpressthemodesofinteractionofthoseparts,andanadequatesetofboundaryconditionsthatspecifythespatialarrangementsofthepartsandtheircausalconnectionsinthatsetting.Thistheoreticalmodelservesasasurrogatefortheputativefeedbacksystemandrelevantportionsofitsenvironment.Theoreticaloperationsonthemodelrepresentphysicallypossibleoperationson

themodeledsystem.

"Obtaining."

Wecanapplythestandardmethodsofphysicalanalysistothismodel.Inadditiontostrictlogicalinferencethededucingoftheoremsfromaxiomswiththeaidofnaturallawsandotherprincipleswemaycomputeaverages,definenewvariables,substitutesimpler,approximatefunctionsformoreac-

curatebutunwieldyones,inventnames,andthelike.Thisprocedureisakindofinference,bothlogicallylooseandcreative,anditiswhatphysicistsandotherscientistsmainlydowhentheyemploybasicscientificprinciples,naturallaws,andempiricalrulesofthumbinexplainingreal-worldobjectsandprocesses."Deriving"istoonarrowawordtoapplytothisprocess,soIshallcallit"obtainingbythestandardmethodsofphysicalanalysis,"orsimply''obtaining."

Truncating.

Oneofthethingswemaydowithacompletetheoreticaldescriptionistotruncateit,toleaveoutportions.Inparticular,wemaydeletesomecomponentsfromthelistofpartsandeliminatetheircausalconnectionstotherestofthemembersfromthelistofinteractions.Thisproducesthetheoreticalsurrogateforasimplersystem.Forexample,inthecompletesetofboundaryconditionsforsystemandenvironmentwehaveamodelfromwhichwecanobtainasubsetforthesystemalone.Thesesimplerboundaryconditionsdescribethesystemasitwouldbehaveifcausallyisolatedfromitsenvironment.Similarly,wecanobtaintruncatedboundaryconditionsthatdesignatewhatoursystemwouldbelikeandhowitwouldbehaveifacertainpartorasetofpartswereabsent.Becausewedonoteliminateanyinformationexceptaboutthepartscrossedoffthelist,weretainacompletesetofboundaryconditionsandlawsfortheremaining,simplersystem.

Obviously,thiskindofoperationonatheoreticalmodelrepresentsthephysicaloperationofcausingthepartorpartstovanishinstantlyfromthecompositesystem,leavingtherestofitmomentarilyasitwasbefore.Thatkindofsurgery,thoughpossiblyofgreatheuristicvalue,canbeexpensiveifperformedontheobjectitself;thatisoneofthereasonswhytheoreticalmodelsaresouseful.Becausecausalconnectionsbetweentwothingsareestablishedthroughmaterial

intermediariessuchasthewiresjoiningathermostattoafurnace,asuitablytruncatedsetofboundaryconditionscanrepresentthesystemwewouldgetafterinterruptingacausallink.Ishallcallsuchasetofboundaryconditionsacomponent-wisetruncationoftheoriginalmodel.

DynamicalAnalysis.

Atheoreticalmodelmayalsobeusedincalculatingwhatwouldhappeninasystemifoneoranotherofitspropertieswereaffectedbyenvironmentalinfluences.We

chooseavariablex,whichtheboundaryconditionsshowtobesubjecttosuchinfluences,insertanumberorsetofnumbersforthechangeinxthatweimaginetobeproducedbytheactionofanenvironmentalfactor,andcalculatethechangesthemodelshowstobeentailedbythisinputforstillothervariablepropertiesofthesystem.

CausalAsymmetry.

Wehavealsonotedthatcausalinfluencesmustpassunidirectionallybetweenactiveandpassiveelementsinthefeedbackloop.Thatasymmetrymustbediscernibleinanyadequatetheoreticaldescription.Supposethatthemodelofasystemallowsforthepossibilityofenvironmentalinfluencesontwovariablesxandyandspecifiesafunctionaldependenceofathirdsystemvariablezonbothofthem.Thentherelationamongx,y,andziscausallyasymmetricinsuchawaythatxandyarecausallyindependentofzwhileitiscausallydependentonthemjustifthefollowingconditionsaremet.Letadynamicalanalysisassignachangeinx(representingexogenousinfluences).Theanalysisthencalculatesresultingchangesinyandzwiththeresultthatzchangesappreciablywhileyremainsessentiallyunchanged.Similarly,aninputchangeinyentailsanappreciablechangeinzandnosignificantchangeinx.Finally,themodelallowschangesinbothxandy,entailinganappreciablechangeinz,withoutcontradiction.

Disconnectability:PhysicalIndependence.

Finally,wehavefounditnecessarytorequirethatsomeofthecausalconnectionsinafeedbackloopbedisconnectablewithoutbreakingothers,simplybytheremovalofsomecomponentpart.Thisfeatureofthecausalprocessesintheobjectsystemisreflectedbyakindofinferentialindependence(i.e.,independentobtainabilityfromthemodel)oftherelationsthatrepresentthem.Ishallcallthisindependenceofrelationsphysicalindependence.Idefineitinterms

oftheboundaryconditionsandthestandardmethodsofphysicalanalysisthus:Onerelationisphysicallyindependentofanotherwithrespecttoatheoreticalmodeljustifthereisacomponent-wisetruncationofthemodelsuchthatthefirstrelationcannotbeobtainedfromitbutthesecondcan.

FormalExplication.

Havingestablishedthesepreliminarydefinitions,wecannowdefinefeedbackasfollows:Supposewe

haveatheoreticalmodelofasetofcausallyinteractingobjectsandoftheirpossibleinteractionswithanenvironment,completeatsomelevelofdescription.Thismodelrepresentsafeedbacksystemjustifthefollowingcriteriaaresatisfied:

1.Fromthemodelandthelawsofphysicsorotherrelevantscienceandempiricalrulesofthumb,onecanobtainbythestandardmethodsofphysicalanalysis(atleast)thevariablesf1,f2,g,andh.

2.Thesevariablesarenotdefinedasfunctionsofthetimevariable,noraretheyrelatedtooneanotherbydefinitionoranyotheranalyticrelation.

3.Accordingtothemodel,thetwovariablesf1andf2,butnottheothers,areavailabletobesetintofunctionaldependenceonother,environmentalvariables.

4.FromthemodelonecanobtainthreenonanalyticrelationsG,H,andF,suchthatGrelatesgtof1andf2,Hrelateshtog,andFrelatesf1toh.Thisrequirementinsuresthatthemodelrepresentsacausalloop.

5.TherelationGiscausallyasymmetric,sothatgiscausallydependentonf1andf2buttheyarecausallyindependentofeachother.

6.TherelationFisphysicallyindependentoftherelationH,andbothofthesearephysicallyindependentoftherelationG.

7.(Herewerequirethatthefeedbackbenegative.)Adynamicalanalysisofthemodel,whichtreatsf2asan"input"variable,changingovertimewithinalimitedrange,yieldsanoutputtime-dependentfunctionforgwhicheitherisfiniteandapproximatelyconstantorvarieswithinfinitebounds.Inaddition,twocorrespondingdynamicalanalysesbasedoncomponent-wisetruncationsofthemodelfromwhichonecannotobtain,respectively,thedependenceofgonhandthedependenceoff1ongyieldothertime-dependentfunctionsforhthatrangemorewidely.

Applications

Ihaveappliedthesecriteriatoavarietyofexamples,truefeedback

systemsandcounterfeits,inmy1984essay.HereIapplythemtoadifferentsetofcloselyrelatedexamples,thesequenceofsafetyvalvesshowninfigure1.Thesequencerunsfrommildlycomplexassemblagesofmovingpartstoanordinaryliddedsaucepan.Ihavechosentheseexamplesfortworeasons.First,the

sequencestraddlestheboundarythatourdefinitionmarksoffbetweenteleologicalsystemsandsimplermechanisms.Theexamplesshowhowthecriterionofindependentdisconnectabilitycandistinguishamongagroupofotherwisesimilardevices.Inaddition,eventhemostcomplicatedofthesemechanismsliesfairlyclosetotheline;Isuspectthattheintuitivejudgmentofsomepersonswouldexcludeallofthem.Theywouldbeexcluded,forexample,byBeckner'sinformalrequirement(1959),whichhestatesinhispreliminaryremarksbutdoesnotretaininhisformalexplication,thattheenergybywhichafeedbackdeviceoperatesmustcomefromaninternalsource.IhavepresentedmyreasonsforfollowingtheexampleofBeckner'sformalrecommendationratherthanhisinformaloneinmy1984essay.

Inalloftheseexamplestheprotectedproperty(gintheformalanalysis)isthepressureintheboiler.Itsvalueisdeterminedbythejointoperationoftwoprocesses:therate(f1)atwhichsteamescapesthroughaventorgapandtherate(f2)ofinfluxofheatfromaflame.Thiscausalconnectionisbestrepresentedbyanequationovertime.Thevariablehthatrespondstopressurechangesisthepositionofthepiston,cap,orlid.Itsvalueisdeterminedbytheopposingforcesexertedbythegasandthespringorweight.Wecanrepresentthiscausalconnectionbyagraph,whichwouldtaketheformofastepfunctionforthegravity-operateddevicesandofanS-curveforthespring-loadedones.Finally,therateatwhichsteamescapesthroughtheventdependsuponthepressureandupontheextenttowhichtheventisuncoveredorthegapopened,andthisinturndependsonthepositionofthepistonorcap.Whenweapplycriterion6,independentdisconnectability,totheseexamples,wefindthatforcasesa,b,andcoffigure1thejudiciousremovalofamaterialportionofthesystemleavesthecausalconnectionsrepresentedbyGandHintactbutparalyzesthecontrollingaction,thecoveringanduncoveringofthevent.Thispieceofsurgeryismosteasilyvisualizedforthefirst

device:Wesimplyremovetherodthatconnectsthesensingpistononthelefttotheslidingvalveontheright.Incasesbandcwefindnosuchremovablemacroscopicpart.However,ifwecutthroughthemetalcylinderwithasawalongtheplaneindicatedbythearrows,wewillremoveamaterialportionofthesystem(whichwilllieontheworkbenchintheformofmetallicdust).Thisremovalwilldisconnectthesensing

Aseriesofpressurevalves,includingapressurecookerandaliddedsaucepan.Theseexamplesshowtheutilityofthecriterionofindependentdisconnectability.Systemsa,b,andcqualifyasrudimentaryfeedbackdevicesbecausetheirdegreeofarticulationissufficienttosatisfycriterion6.Systemsd,e,andf,however,donotcontainapartwhoseremovalwoulddisruptthecontrollingfunctionwhile

leavingthesensingfunctionintact.

motionofthepistonfromtheslidingmotionofthevalvejustaseffectivelyasdoestheremovaloftherodinthefirstcase.1Althoughexamplesbandccanthusbeshowntosatisfycriterion6,noanalogoussurgicalprocedureavailsfordevicesd,e,andf.Intheseexamples,anyremovalofmetalthathaltstheopeningandclosingofventorgapalsodisruptsthesensingaction.Thesedeviceshavetoofewindependentcausalconnectionsforthemtoqualifyasfeedbacksystems;theirdesignistoosimple.

Yetthenonteleologicalsystemsperformthetaskofreleasingexcesspressurenolesseffectivelythandotheirmorecomplexrelatives.Soweseethatourexplicationoffeedbackcommitsustothepropositionthatasystem'sbeingteleologicalisnotamatterofhowsensitivelyorefficientlyitperformsthetaskwehavesetforit;itisinsteadsimplyamatterofhowelaboratelyandwithwhatmannerofcomplicationitdoesso.

Thecriterionofindependentdisconnectability,whichdistinguishesamongthesafetyvalvesoffigure1,alsodiscriminatesbetweenfeedbacksystemsandaproblematiccaseproposedbyLowellNissen(1981)inhiscriticismofNagel'scyberneticaccountofteleology.NissenclaimsthatNagel'sanalysisincludestheprocessbywhichatmosphericconvectioncoolsageographicalareathatsunshineheatsabovethetemperatureofneighboringareas.(Thesameprocessoccursastheairaroundanincandescentlightbulbisheatedbythewarmthofthelamp,rises,andallowscoolerairtomoveuptoreplaceit.)Thissystemdoesnotdefineitsaimed-attemperaturerangebyturningonandoffatdefinitetemperaturesasanordinarythermostatdoes.Nevertheless,convectivecoolingresemblesthermostaticcontrolinthatonepartofacompositesystemrespondstotheincreaseintemperatureofanotherpartinsuchawayastoreduceitsextent.Shallweadmitconvectivelycooledlampsandislandscooledby

1/Hereweseetheusefulnessoftheatomistreductionprogram.Whileapplyingthesawwemustviewthecylinderoneofthecomponentsofthefeedbacksystematthefirstlevelofanalysisasbeingitselfcomposedofstillfinerparts,whichtheteethofthesawcanrevealtous.Thisillustratesthegeneralprinciplewenotedinchapter1,namely,thatattemptstodescribeasystem'scausalconnectionsconsistentlyatachosenlevelofanalysisoccasionallymustyieldtothenecessityofintroducingentitiesatstilllowerlevels.Inthiscase,weacknowledgethataforceexertedononeendofthemetalrodreachestheotherendbymeansoftheactionsoftheinterveningatomsontheirneighbors.

seabreezestotheclassoffeedbacksystems?Ifso,thenNissencouldrightlycomplainthatouranalysisqualifiesalmostanyobjectintheworldasagoal-directedsystem.Butitdoesnotqualifyconvectivecooling.Theprocessisnotcomplexenough,notintherequiredway,foritcontainsnopartwhoseremovalwouldretainthe''sensing"connectiontotheatmospheretheheatingofthesurroundingairwhilebreakingthe"correcting"connectionthereplacementofthiswarmerairbycoolerfrombelow.

AssessmentoftheReduction

Theaimoftheforegoinganalysisoffeedbackhasbeentoforgeaconceptualtoolsuitableforthemechanisticreductionoftheteleologicaldescriptionsandexplanationsofbiology.Thisaccountofteleologyoccupiesacentralplaceintheatomistprogramforreducingtheorganicsciences,whicharedistinguishedbytheiruseofsuchconceptsandexplanations,tothesciencesofinertmatter.Isubmitthattheattempthassucceeded,fortworeasons.

First,theanalysismakesnoreferencetoteleologicalprocessesinotherportionsoftheworld.Itdoesnotrefer,forexample,totheintentionsofthedesigner,manufacturer,oremployerofthefeedbackcontrivanceortoanypersonorcontainingmechanismthathasselectedthedeviceaccordingtosomecriterionorforsomepurpose.Thiscorroboratestheearlierconjecturethatthegeneralthrustofacyberneticanalysistendsinwardanddownward,tothepartsofanupper-levelthingandtotheircausalinteractions.True,theexplicationdoesnottreatfeedbacksystemsincompleteisolationfromotherthings,becauseitstipulatesthatthepropertyrepresentedbythevariablef2beopentodisturbancesfromtheenvironmentandthattheotherpropertiesrepresentedbytheothervariablesbefreefromoutsideinfluences.Nevertheless,theoutward-pointinglinesleadfromindividual,lower-levelfeaturesorpropertiesofthesystemthrough

causalchannelscomposedoflower-levelparts.Forexample,wehaverequirednomoreofathermostaticallycontrolledcomplexofpartsthanthatanobjectoutsidethesystembeabletodrawheatawayfromit,therebyofferingsomethingforthethermostattocorrect.

Second,becausetheexplicationconcernsthecausalinfluences

thatpassfromonematerialthingtoanotherwithinthedevice,thefurtherreductionoftheconcepttostilllowerlevelsofanalysiscanproceedalongwell-troddenpaths.Causalconnectionsthatmayappearasmysterious,unanalyzedfactsatanupperlevelofdescriptionbecomecleareraswedescendtothedescriptivemodethatnamesthemicroscopicentitiesthatmediatethem.

Itmustbeadmittedthatthetheory-referringexplicationisarelativeone,foritisstatedintermsofphysicallawsandempiricalrulesofthumbthatrepresentthebestthatphysicsorsomeothernaturalsciencecanofferatthepresentstageofitsdevelopment.Theselawsareofhumanconstruction,fallible,andsubjecttochange.Nissen(1981,p.130)seemstosuggestthatanexplicationsorelativizedcannotshowfeedbacktobeanobjectivepropertyofsystemsastheystand,self-contained,independentofhumandesiresandintentions.Butourplightisbynomeanssodire.Wehaveanalyzedfeedbackintermsofhumanknowledgeabouthowtheworldrunsgenerally,butthatfactsimplyplacestheclaimthatsomethingisafeedbacksystemonthesamefootingastheclaimthataccelerationsareproportionaltoforces.Botharefallible,butneitherimportsacovertreferencetohumanteleologyintoadiscussionofthenonhumanworld.

Itmustalsobeadmittedthatthisreductionoffeedbackdoesnotconformtothestandardsoflogicalrigorsetbythereductionofthermodynamicstostatisticalmechanics.Inthatparadigmoftheoryreductiononeproceedsbycarefuldefinitionandstrictimplicationtoderivethelawsofthemacroscopictheoryfromthelawsofthemicroscopicandtheprinciplesofstatistics.ThepresentanalysishasmadeextensiveuseofwhatIhavecalledobtaining,alogicallymuchlooserformofreasoningthatproceedsbymeansofaveragingandapproximating,aidedandabettedbyempiricalrulesofthumbandalltheothertricksoftheappliedphysicist'strade.InexplicatingfeedbackIhavenotshownhowonemayderiveastatementsuchas"thisobject

isafeedbackdevice"fromstatementsthatassignpropensitiesandrelativepositionstoasetoflower-levelthings.Rather,Ihaveidentifiedacertainsortofpatternofcausalinfluencesthatcanbefoundinsomecollectionsofinteractingparts,identifiedacorrespondingpatternoflinguisticrelationsinthetheoreticaldescriptionswemakeofsuchcollections,andshownhowtorecognizethelattersortofpatterninanydescriptionofthesameobjectsmadeatstill

lowerlevels.Inshort,wecanobtainacharacterizationofamacroscopicobjectasafeedbackdevicefromlower-leveldescriptionsonlybyexercisingourabilitytorecognizepatterns.Butthisadmissiondoesnotinanywayweakenourclaimtohaveproducedathoroughlymechanisticreductionofthiscyberneticconcept.Nothinginouranalysiscouldencourageanantireductionistinthinkingthatateleologicalsystemdefinedinthiswayissuchathingbyvirtueofanythingotherthanthespatialarrangementsandmechanicalinteractionsofitsmicroscopicparts.Itstillappearsthatateleologicalsystemisjustoneofmanyinterestingpatternsofactivitygeneratedbyatomsastheydashtoandfro.If,asIshallargueinchapter5,tobeagoalseekeristobeorganizedaccordingtothefeedbackpattern,thentheseekingofgoalsisjustoneofthethingsthatatomsdowhentheyhappentofalltogetherinacertainway.

FiveTeleology:GoalsandAdaptationsWithareductiveexplicationoffeedback,wehavemadethefirststeptowardreducingtomechanisticnotionsanyconceptexplicableintermsofit.Acyberneticanalysisofteleologyisanavenuethroughwhichtodrawtheorganicsciencesintotheempireofthephysical.Thischapterexploresthatroadbyaddressingthefollowingquestions:

1.Cangoalseekingbeexplicatedbymeansoffeedback?

2.Cananorganism'soramechanism'sgoalsbeidentifiedbyreferencesolelytothestructureandactivitiesofthethingitself,apartfromtheintentionsofitsemployerordesigner?

3.Canwesatisfactorilyunderstandtheteleologicalideasandexplanationsofbiologyintermsoftheseekingofgoals?

Irespondwithqualifiedaffirmativestothesequestions.Iarguethatbiologistsemploythenotionsofadaptation,function,andgoalintwosenses,astrongoneandaweaklyanalogicalone;andthatthecyberneticanalysissatisfactorilyaccommodatestheformer,whereastheselectionisttheoryfailstodoso.ButIalso

arguethatanapparentlyimportantclassofteleologicaldescriptionsandexplanations,thosehavingtodoprimarilywithreproduction,donotsleepcomfortablyinthecyberneticbed.Tounderstandtheseexamplesofteleologicallanguagewemustlookforhelptotheselectionisttheory.Althoughthisfailuretoaccommodatereproductivesystemsmayseemafaultofcyberneticism,itisinfactasuccess.Ishallarguethatcyberneticismdiscriminateswhereascientificallysignificantdistinctionshouldbemade,whereastheselectionistanalysisdoesnot.

Ifamechanismdoesseekagoalofitsown,thesought-forconditionmustbeastateofaffairsthattheactionofthemechanismtendstoachieveundersomepossiblecircumstancesand,havingachievedit,eitherrestsorentersa''hunting"phasearoundthegoalstate.Thisisanecessaryconditionofsomething'sbeingthegoalsoughtbyamechanismbutcertainlynotasufficientone:Evenapendulum"hunts"arounditsequilibriumpositionandtendstoceaseitsactivitywhenthatstateisachieved.Therefore,onobservingathermostat'sactionswhentheroom'stemperaturerisesaboveacertainvalueanddropsbelowalowerone,wemayspeculatethatthedeviceseeksatemperaturewithintherangeboundedbythosetwovalues.Buttheconjecturemustbetestedbyfurtheranalysis.

Whetherhumancontrivancesseekgoalsornot,theirdesignersanduserscertainlydo.Andthegoalofamachine,ifithasone,maynotcoincidewiththeonesoughtbyitsemployeror,inthecaseofsocialmachinery,byitscomponentparts.Ahouseholdermayinstallathermostatinthedomesticheatingsystemwiththeintentionofkeepingtheroom'stemperatureascloseto20°Caspossible;butanincandescentlampplacedtooclosetothisfeedbackdevice,oranicecubebalancedontopofit,willsoonrevealthatthemachineryitself,ifitaimsatanythingatall,aimsatatemperatureof20°Conlyforitsownbimetallicstrip.Asimilardisparityoccurshigheruponthescale

ofteleologicalsystems.Thepolicyofpromotingcivilservantswhodemonstrateanadequatecompetencetopositionsofgreaterresponsibility,andofnotdemotingthosewhoperforminadequately,maybeintendedbythemakersofthepolicytoachievetwoends:optimallytodeploythevariedtalentsofadministratorsandtoavoidthegrumblingofdemotedemployeeswhoarelearningtocopewithre-

strictedsalaries.Butifthispieceofsocialmachineryhasanygoalofitsown,itmustbethestateofthingsthatthepolicytendsnottoalter.Andthatstate,accordingtothePeterPrinciple,distributesamoderatebutconsiderabledegreeofincompetenceateverylevel.Similarly,wemaythinkthatthemachineryofrepresentativebureaucraticgovernmentaimsatthewelfareofeachindividualcitizenortheincreaseofjoyandcontentmentinthecommonwealthasawhole,butelectedlegislatorsinfactaimatsuchgoalsonlywhentheylieinthesamedirectionastheirrealtarget,thegainingofanothertermofoffice.Bureaucratsseeknotsomuchthepublicbenefitasthesmoothoperationoftheirowndepartments,followingMacaulay'sironicdictumthat"alliswellthatrunsquietly."Thisdiscrepancybetweentheaimsofthebuildersofsocialmachineryandofthemachineryitselfaccountsforapervasivefeatureofmoderngovernment,namely,acontinualtinkeringwithtaxcodesandthechartersofregulatingagencies,pilingupcorrectiveadditionsinthehopethatthistimethemachinewillsteerstraight.

Examplessuchastheseshouldputusonguardagainstimputingtooreadilytoallegedlygoal-seekingmachinerytheaimsofitsusers.Besides,therecanbenodoubtthatincallingamachinegoal-directedwestretch,perhapstoofar,therangeofapplicationofaconceptoriginallydesignedforhumanintentions,desires,andbeliefs.Yettheascribingofgoalstomachinesseemstobeappropriateinsomecases.Cantheconceptoffeedbackjustifythispractice?

AndrewWoodfield(1976)claimsthatwhenweascribegoalstomachineryandthelowerformsoflifeweexploitananalogytohumanmentalactivity.The"coreconcept"aroundwhichallofourtalkofteleologyhasgrownuphastodowithdesireandbelief.Iftheascriptionofagoaltoamachineisjustifiedatall,itisonlybecausethemachine'soutwardbehaviorresemblesgoal-seekinginsentientbeingsanditsinnermodeoforganizationislikeadesireinsome

essentialfeature.Withoutclaimingtospelloutthesimilarityindetail,Woodfielddoessetdownanecessarybutnotsufficientcondition,namely,thattheinternalstatemustrepresentthegoalstate.Itisnotclear,however,justhowamentalimagerepresentsitsobjectiftherearesuchthingsasmentalimages.Woodfieldacknowledgesthedifficultybynotattemptingtogivenecessaryandsufficientconditionsforrepresenting.YetI

believehissuggestionmaybehelpful,providedwedonotplaceundulyheavyrequirementsontheideaofrepresentation.Weshouldnot,forexample,requirethattheinternalstateofthemachinerepresentthegoaltothemachineitself.Instead,weshouldmerelyrequirethatthisinternalstructureofthemachineryrepresentthegoaltous;thatis,thatfromaknowledgeoftheinnerworkingsofthemachine(andperhapsofitsnormalenvironmentIshallreturntothispossibilitybelow)weshouldbeabletoinferwhatstateofaffairsthemachineisworkingtoward.

WhetherornotmylooseinterpretationofrepresentingaccordswithWoodfield'sintentions,theprogramIhaveadoptedrequiresmetotakeissuewithhimoverthekindofanalogythatisinvolvedinextendingtheconceptofgoalorientationfromhumanstosimplercreaturesandtomachines.Imustleavethequestionentirelyopenastowhetherthereductionprogramofatomismcanbecarriedintothetraditionalpreserveofmentalisticconcepts.Woodfieldmaywellbecorrectinassertingthatthereisamereanalogyatworkhere,somesharedabstractfeatureofthementalentitiesthatconstitutehumanteleologicalstatesandthephysicalentitiesthatmakeuptheinternalstatesofgoal-directedmachinery.However,theatomistreductionprogramaimstoconstructanunderstandingofdesiresintermsofpatternsofcausalconnections.Ishall,therefore,leaveopenthepossibilitythat,evenforahumanbeing,orientationtowardagoalconsistsinhavingthenervoussystemorganizedaccordingtothefeedbackpattern.

Despitehisappreciationofthecybernetictheory,Woodfieldclaims(1976,p.193)thattheconceptoffeedbackcontrolcannotexplicategoal-directednessfortworeasons.First,theclassesofobjectstowhichthetwoconceptsapplyoverlaponlyimperfectly.Onlythosefeedbacksystemsaregoal-directed,heclaims,thathavesomeadditional(unspecified)properties."Feedbackloopsareubiquitousin

electronics,buttheydonotcreategoal-directednesswherevertheyappear"(p.189).Andnotallgoal-orientedbehaviorparticipatesina"processorasequence,thepreciseunfoldingofwhichisguidedbyperceptions"(p.191).Becausethekindsofthingsexplainedintermsoffeedbackdonotoverlapexactlywiththethingsexplainedintermsofgoalorientation,thereisno"possibilityofanydirectreductionofonekindofexplanationtotheother''(p.191).

Woodfielddoesnotciteexamplesofthefeedbackloopssocommoninradioandtelevisionequipmentthathedisqualifiesasteleologicalsystems,butIsuspectthathehasacceptedtheengineers'verylooseemploymentoftheterm.Manyexamplesofpopularusagearedisqualifiedbytheexplicationpresentedabove.Whatiscalledafeedbackoscillator,forexample,doesnotsatisfythecriteria;suchanoscillatorworksbyso-calledpositivefeedback,whichdoesnotinvolveanysortofcontrolbytheloop.

AndWoodfieldissimplymistakeninrequiringthat,forfeedbacktoplaythedecisiveroleinqualifyingapieceofbehaviorasgoal-oriented,thebehaviormustbeguidedinits"preciseunfolding"bythefed-backperceptions.Hecitestheexampleofacuttlefishflingingoutitstentaclestograspashrimp:Oncethemusculardischargehasbegunthereisnopossibilityofcorrectingtheaimiftheshrimpshouldmove.Tothisexamplewecouldaddtwomore:Apersonreachesouttograspacoffeecupfromafamiliarspotonthetablewhilelookinginanotherdirection;andaspring-loadedrelayswitchsnapsshut,turningonafurnaceinresponsetoaweakelectricalimpulsefromathermocouplemountedonthewallofasittingroom.Ineachoftheseexamples,somekindofactivityoccursthatisgoal-directed,inthesensethatitpromotesthereachingofagoalbythesystemthatcontainstheactivepart;yetthepreciseunfoldingofthebehaviorisnotsubjecttocontrolbyperceptionorotherfed-backinformationaboutitseffects.Althoughthepersoncouldestablishsuchadetailedguidancemechanismsimplybywatchingtheprogressofthehandtowardthecup,nofeedbackofthissortinfactoccurs;andtherelayswitch,havingbeenpushedpastitsbalancepointbyasmallelectricalimpulse,flipscompletelytoitsclosedpositionundertheforceofaspring,whetherornotthetemperatureofthethermocouplechangesduringthisfractionofasecond.

IsubmitthatWoodfieldhasidentifiedausefuldistinctionhere,buthis

skepticalconclusionisunwarranted.Wemustdistinguishbetweenthegoal-directednessofawholesystemandthegoal-directednessofsomeofthebehaviorandinternalprocessesofthesystem.Accordingtothecybernetictheory,asystemisorientedtowardagoalbyvirtueofitsorganizationinthefeedbackpattern,andasampleofbehaviororaninternalprocessmaybesaidtobedirectedtowardthatgoalifitcontributestoitsachievement.Becauseonlysufficientlycomplexsystemscanbegoal-

oriented,theirpartsandbehaviorearnthatepithetonlyderivatively,onlyiftheycontributetowardthegoal-seekingactivityofthetotalsystem.Iconcludethatthefreedomfromdetailedcontrolofsomeoftheachievement-promotingprocesseswithingoal-seekingsystemsgivesusnoreasontoabandonthecybernetictheory.Thesystem,accordingtothisconjecture,aimstowardagoalbyvirtueofitsfeedbacklooporloops,andthebehaviororotherprocessisaimedbyvirtueofitsparticipationinoneormoreofthoseloops.

Woodfieldalsodiscussesanotherhelpfuldistinction,sortingteleologicalactivityintothreetypes:seeking,aiming,andkeeping.Keepingistypifiedbythethermostat,whichmaintainsavariablepropertywithinlimits;aiming,byanautomaticpilotorguidedmissile,whichhomesinonatarget.Butthis,too,isasortofkeeping,becausethehomingoccursbymaintainingacompassreadingwithinnarrowboundsorbykeepingtheimageofatargetwithinthesightsofthetrackingdevice.Seekingisdonebycertainguidedmissiles,whicharedesignedtoscaninvariousdirectionswhennotargetiswithintheirsights.Thisactivityisalsodirectedtowardthegoalofthemissileyetisnotitselfcontrolledbyfeedback.Havewehereanexampleofagoal-orientedmechanismorprocessthatfallsoutsidetheterritorymappedoutbytheconceptoffeedback?Again,thatconclusionwouldbeunwarranted.Imagineamachinewithascanningprogramthatisnotalsoprogrammedtobeginhomingwhenatargetappearswithinitssightsbutjustgoesonswivelingitselectriceye.Wewouldhardlywanttocallsuchbehaviorseeking.Althoughthescanningbehaviorisnotitselfunderfeedbackcontrol,itsconnectiontoafeedbackmechanismiswhatjustifiesourcallingitgoal-oriented.

Onceagain,ananalysisoftheconceptofgoalorientationhasledbacktotheconceptoffeedback.Iconclude,despiteWoodfield'scautiousskepticism,thatwemaycontinuetoentertainthecyberneticconjecture.

ErnestNagel(1977)reachesthesameconclusioninhisdiscussionofWoodfield'sarguments,thoughbyanotherroutethantheoneIhavetakenabove.Morerecentlystill,LowellNissen(1981)hascriticizedNagel'sposition,bringingnewexamplestobearinsupportofthesessimilartoWoodfield's.Nissenclaimsthatfeedbackisnotasufficientconditionforteleology,citingcasesofallegedfeedbackthatareclearlynotgoal-oriented.Hisexamples

oftheconvectivecoolingofanislandbybreezesfromthesurroundingoceanIhavediscussedearlier,showingthatitfailstosatisfythecriterionofindependentdisconnectabilityinmyproposedexplication.AsIunderstandthem,allofNissen'sproposedcounterexamplesfailtosatisfythiscriterion;thatis,theyaresystemsoftoolittlecomplexity.Iconcludethatthechargethatfeedbackisinsufficientasaconditionofgoal-directednessisstillunproven.ButNissenalsocontendsthatfeedbackisnotnecessaryforteleology,citingartifactssuchashammers,which,beingusedintheachievingofgoals,havefunctionsyetarenotfeedbacksystems.Ahammerhasitsfunctionbecauseoftheintentionsofthepersonwhograspsit,soNissensuggeststhatmentalisticconceptssuchasintentions(possiblynonconsciousones)maybeneededtoconstructacompleteanalysisofteleology.ThiscriticismcanbemetwiththesameanswerIproposedtoasimilaroneofWoodfield's.Wemustdistinguishtwosensesoftheterm"goal-oriented."Anobjectoradynamicalprocessmayaimatagoalthatis,itmaybeafull-fledgedteleologicalsystemor,likethehammer,itmaybeaimedbyasystemoftheformersort.Boththesystemthatactivelyaimsandtheonethatisaimedmayqualifyasgoal-directedbyreferencetoacyberneticanalysisoftheformer.

Havingclearedtheseobstaclesfromourpath,Imustnowshowthatwecanwalkitandthatitleadstoasatisfactoryunderstandingofteleologyinbiologicalsystemsandinhumanartifacts.

IdentifyingGoals

Canweextendtocertainmachinesandtosimplebiologicalorganismsthepropertyofhavingorseekingagoal,withoutstretchingthenotiontoofar?Andcanwedothisinsuchawaythatthegoals,purposes,anddesiresofhumanbeingscanbeunderstoodasnothingotherthanespeciallycomplexinstancesofwhataservomechanismcando?Canwe,inshort,understandhumanteleologicalbehaviorintermsof

interlockingfeedbackloopsandofnestedhierarchiesofthem?

Letusexcludeconsciousness,conceivedasanonphysicalthingorproperty,fromourdiscussionasamatterofpolicy.Noharmshouldresultfromthisexclusionforawiderangeofgoalseekingsystems,becauseevenhumanbeingscanhavegoalsanddesiresofwhichtheyarenotaware.Indeed,nodifficultyneed

ariseatanystageifthephysicalisttheoryofmindcanbemadetowork.Letusnotassumeherethatitwillfail.Andletusproceedinductively,startingwiththesimplestcases,namely,feedbackloops,andproceedingfromthatbasetoreconnoitertheterrainofmorecomplicatedsystems,glancingoccasionallytowardthedistantrangesofhumanintentionality.

Consider,then,athermostat.Doesitseekagoal?IhaveagreedwithWoodfield(1976)thatanecessaryconditionforanaffirmativeanswertothequestionisthatthesystemshouldrepresent(inaveryloosesense)itsgoalstate;thatis,weshouldbeabletoinferthegoalstatefromourexaminationofthesystem'sanatomyandinnerworkings.What,then,canwelearnaboutthestateofaffairsthatisaimedatbyathermostaticallycontrolledhomeheatingsystem?Thecorrectingactionofthedevice,theopeningorclosingoftherelayswitchthatturnsafurnaceonoroff,istriggeredbytherisingorfallingofthetemperatureofthethermostat'sbimetallicstrip.Thetwotemperaturesatwhichthesedistinctresponsesoccurdefinearangeoftemperature.Sowediscoverthatthesystemdiscriminatesbetweentwosortsofsensoryinput.DoesitalsoexhibittheplasticitythatNagel(1977,p.272)suggestsisanotherhallmarkofteleology?Yes,butonlytoaverysmallextent.Itoperateslessflexiblythanthetemperaturehomeostatofawarm-bloodedanimal,whichisaparadigmoftheplasticityNagelrefersto.Tomildenvironmentalthreatstothestabilityofbodytemperaturethehomeostatrespondsbyconstrictingordilatingbloodvessels;anditmobilizesstrategiessuchasshiveringtomeetgreaterthreats.Theplasticity,suchasitis,ofathermostatconsistsmerelyinitsabilitytorespondintwodistinctwaystodistinctthreats.Thesystemisnotelaborateenoughtocommandstillstrongermeasuresif,forexample,heatescapesfasterthanthefurnacecanreplaceit.Still,wefindthatthethermostataimsatacertainconditionofitsbimetallicstrip,namely,itshavingatemperaturewithintherangedefinedbythe

device'stworesponses.

TheContextRelativityofMachines

Doesthethermostatseekatemperaturewithinthatrangeforthewholeroominwhichitissituated?No;aswehavenotedabove,carelesslyplacedincandescentlampsoricecubesrevealthatthefeedbackloopconsistingofthermostat,switches,furnace,and

heatingpipescontrolsonlyitsowninput,whichitreceivesbymeansofitsthermalsensor,thebimetallicstrip.Thegoalofmaintainingtheroom'stemperaturewithinthoselimitsbelongstoamorecomplexsystem,namely,thehouseholderwhohasinstalledthedevice.Thesimpleloopactsinsuchawaythatinnormalcircumstanceslampsandicecubesbeingkeptawayfromthesensorthehouseholder'sgoalwillberealizedasanincidentalresultofthethermostat'sachievingitsown.

Thissimpleexampleshowshowimportantthecontextmaybeforourattemptstodiscoverthegoalsofcyberneticmachinerywithoutimposingourownintentionsonthem.Andthecontextresolvesotherambiguitiesaswell,asthefollowingexamplesshow.

Thetheory-referringdefinitionoffeedbackassignsthevariablesf1,g,andhtodistinguishablepositionsintheloop.TherelationGconnectinggtof1,f2...mustbecausallyasymmetric,butwehavenotrequiredthatpropertyforHandF.TherelationFbetweenf1andgmustbedisconnectableindependentlyoftherelationG,butwehavenotrequiredthatGbedisconnectablewithoutbreakingF.Becauseofthisunequalparticipationintheloop,wecaninthemostgeneralcasedistinguishtheprotectedvariableh1,fromtheothers.Therefore,ascrutinyoftheinternalstructureoftheloopwillshowunambiguouslythatgisthepropertyatwhosestabilitytheloopaims.Butspecialcasesofgreatersymmetrymayarise:Allthreerelationsmaybecausallyasymmetric;allthreemaybedisconnectableindependentlyoftheothers.Insuchacase,thepropertiesrepresentedbyf1,g,andhparticipateequallyintheloop.Anyoneofthemmightbetheprotectedvariable.Theambiguityclearsup,however,becausethedefinitionpointstothecontext.Themodelmayspecifythatthevariablef2actsastheprincipalportofentryforenvironmentaldisturbances;otherlociintheloopdonotreceivedisturbancesfromoutside.Onlythegpropertyneedsprotectionbytheloop;therefore,

itsstabilityisthedevice'sgoal.

Wemustemploythedistinctionbetweenanactivedeviceandthecontextinwhichitsactionoccursalsowithinthefeedbackloop,becausethedefinitiondistinguishestheregulatorfromtheregulatedsystemthatcontainsit.Hitherto,Ihaveappliedtheepithet''goal-directed,"initsprimary,activesense,totheentirefeedbackloop.Butacasecanbemadeforascribinggoalsmorenarrowlytotheregulatoritself.Athermostatoranautopilotoc-

cupiesthesameplaceinitscompleteloopasthehouseholderorhelmsmanforwhomitsubstitutes.Whentheregulatingisdonebyapersonwelocatethegoalorientationmorepreciselyinthisorganicregulator;whynottreataninorganicservomechanismasgenerously?Arethererelevantdifferencesbetweenanautopilotandahelmsman?

Ihaverequiredthatanygoalweascribetoamechanismmustbediscoverablejustfromaninspectionofitsinnerworkings.Ifwestudyanautopilotapartfromtheboatitsteers,wefindnocluethatthereadingofitsbuilt-incompassisdesignedtocoincidewiththecourseoftheboatorthatitsoutputnormallymovesthetillertoportorstarboard.Neitherdoesthestructureofthedevicealonedictatethatitshallbeplacedonlyinthekindofsettingforwhichithasbeendesigned.Ignoringtheclearinstructionssuppliedbythemanufacturer,wemightreversetheoutputby180degrees,sothatthedevicepushesthetillertoportwhenstarboardisneededtorestoretheboattoitscourse.Thiswouldbeaninstanceofpositivefeedback,notacontrollingorkeepingdeviceofanysort;thesystemwouldhavenogoal.Andothersettingscanreadilybeimaginedinwhichtheautopilotparticipatesinanegativefeedbackloopwhosegoalisquitedifferentfrommaintainingaboatoncourse.Forexample,itmightbeinstalledinanelevatorsoastocauseittomoveupanddowninstepwithasecondonemovinginaparalleltrackandcarryingamagnetwhosefieldtheautopilotsenses.

Somecontextrelativityseemsinescapableifwewishtoascribegoalstothesensor-controllersubsystems.Providedwespeakofgoalsverynarrowly,thatis,onlyintermsoftheregulationofsensoryinput(thereadingoftheautopilot'sinternalcompass,thetemperatureofthethermostat'sbimetallicstrip),wemayassignthegoalwiththemodestproviso,"relativetoacontextinwhichthedeviceactsasthesensorcontrollerinanegativefeedbackloop."Ifwewishtocalltheautopilotamechanicalhelmsmanorthethermostataregulatorofroom

temperature,thenwemustspecifythepotentialcontext,relativetowhichthegoalisascribed.Asimplesensorcontrollerdoesnotdefineitsowncontext.

HumanContextRelativity

Howdoesahumansteersmanfarewhenputtothissametest?Ifdisconnectedfromthetiller,theoutputarmoftheautopilotwill

continuetopushoutandpullinasthecompassneedleswingsabout,butnosteeringisdone.Yet,ifweknockthehelmsman'shandfromthetillerhewillreachouttograspitagain;ifweloosenthescrewsthatholdthecompasssecurelytoabulkheadhewilltightenthem;ifwelifttherudderfromitsgudgeonshewillreplaceit.Theinternalstructureoftheperson'snervousandmuscularsystemsbywhichheperformstheseactionshelpstodefinetheirpropercontext,namely,amovingboatinwhichthecompassindicatesthecourseandtherudderinfluencesit.Thiscontextjustifiesoursayingthatthesteersman'sgoalisacertaincoursefortheboat,notmerelyacertainreadingforthecompass.Andonecouldcontinuethisanalysisfurther.Ahumansteersmancontainsanimmenselycomplicatednetworkofsensor-controllermechanisms,interlockingandhierarchicallyarranged.HisgoalisnotmerelyasouthwesterlycoursefortheboatbutarrivalinTahiti,andnotmerelythatbutlivingamongpeacefulneighborsandtreesfulloffruit.Theautopilotcannotsharethesailor'sdreamofaneasylifeorevenhissubsidiarygoalofarrivinginTahiti.Themostthatwecandeducefromitsstructureisthat,provideditisconnectedintoanegativefeedbackloopofsomekind,itwilltendtoregulateitsownsensoryinput,tomaintainthereadingofitsinternalcompasswithincertainlimits.Howcouldwealteritsoastomakeitmoreexpressiveofitspropercontext?Thisquestionamountstoaskinghowtobegintoconstructaworkingreplicaofahumanbeing.Clearly,wecanproduceonlyanin-principleanswer,butasafirststepinthatdirectionletusaskhowtocomplicatetheautopilot'sstructuresothatitwouldmorenearlydefineitspropercontextasthesailordefinedhisinreachingforthetiller.Tothissmallproblemtheanswerisobvious:Weaddanotherfeedbackdevice,thisoneahomingmechanismthatdetectssomeopticalfeatureofthetillerandhomesonit.

Butthemechanismcandetectonlyafinitesetoffeatures.Hence,itcouldbefooledbyimitationsofvarioussorts,asaheat-seeking

missilecouldbedrawntowardthesun.Theautopilot'snewgoal,builtintoitsinternalstructure,isamorecomplicatedsortofsensoryinput,namely,bothacertaincompassreadingandacertainsortofstimulationofitsopticalsensor.Andifthisstepistypicalofthedauntinglymanywecouldtakeinprincipleasweconstructatrulyinterestingautopilot,thenwemustadmit

thatwecannot,eveninprinciple,makeamachinethatwantstosailtoTahiti.Atbest,wecouldmakeonethatseeksthesortofsensoryinputthat,inthenormalconductoftheworld'saffairs(rulingoutmalevolentdemons,etc.),couldbeobtainedonlyifithadguidedaboattoTahiti.

Butthatadmissioninnowaydamagestheplausibilityoftheatomistprogramforreducingteleology.Thesamedifficultyappliestohumanbeings,thoughmoresubtly.Ouruncertaintyoverwhetherthemachineseekstheislandormerelythenormalsensoryevidenceofbeingtherereflectsthegeneralproblemofepistemologicalskepticism.Surely,thecybernetictheoryofteleologymaybeexcusedfromtryingtosolvethisancientriddle.Indeed,itscroppinguphere,ifitdoesanythingtotheplausibilityofthetheory,enhancesit.Anygoalascriptionmustcarrysomeprovisoaboutnormalsettings,evenforhumanbeings,theparadigmsofteleology.Itis,therefore,noblemishonthecybernetictheorythatit,too,mustmakeitsgoalascriptionsonlyrelativetocontexts.

HierarchiesofLoops

ThevoyagertoTahitiillustratesanotherpervasivefeatureofmorecomplexgoal-orientedmachines,namely,thattheyhaveahierarchicalorderofultimateandsubsidiarygoals.Thisfeature,too,canbeillustratedwithsimplefeedbackloops.Anautopilot,forexample,mightconsistofacompasscontainingafluidthatissensitivetovariationintemperatureandathermostatthatmaintainsthetemperatureofthecompasswithintherangerequiredforitsproperfunctioning.Theultimategoalofthisdeviceisthesteeringofacertaincourse,andasubsidiarygoalisthekeepingofacertaintemperature.Wecaneasilyunderstandintermsofouranalysisoffeedbackwhythiskindofmutualsupportamongfeedbackloopsisgenerallypossible.Agivenloopcanactasaregulatorofitsgproperty

onlyifotherpropertiesremainnearlyconstant.Iftheenvironmenttendstoperturboneoftheothers,asecondfeedbackloopmaybeconnectedinsuchawayastoregulateit.

Intricatenetworksofinterlockingfeedbackloops,eachdependentforitsownstructuralandfunctionalintegrityontheregulatingactionsoftheothers,typifythemachineryoflife.Ifthetemperature-regulatingmechanisminawarm-bloodedcreature

allowsitstemperaturetorisetoofar,noneofitsotherhomeostatscancontinuetofunction.

Flexibility

Thegoalsofthesekeepingmechanismsremainwiththeorganismthroughoutitslife,andthematerialelementswhosecausalinteractionsmakeupthefeedbacklooparepermanentcomponentsoftheorganism'sbody.Butsomeorganismsareable,also,toacquireanddiscardtemporarygoals.Theydothisbyconnectingthemselvesthroughexternalsensorsandeffectorstocausalloopsthatextendpartlyoutsidetheirbodies.Inthesefeedbackloopsthef1property,forexample,maybelongtoanexternalobject,andthecausalconnectionsofsensingandeffectingmaybebrokenbyactionsoftheorganismitself.Thisabilityoftheorganismtocompletevariousfeedbackloopsbytakingontheroleofthesensorcontroller,andtodisassemblethemagain,istypicalofthehigherorganisms,especiallyanimals.Butthepresenceofmutuallystabilizingself-containedinternalfeedbackloopsistypicaloflifeitself.

Surviving

Apatternofmutuallystabilizinginternalfeedbackloopsonalargeandintricatescaleisoneofthetwogeneralanddistinguishingcharacteristicsoflivingthings.Theotheroneisreproduction.Ofthetwo,onlytheactivemaintainingofstructurecanbecalledanessentialcharacteristicoflife,becauseasterileorganismmaybeverymuchalive,butonewhosefeedbackloopshavelosttheirmutuallysupportiveintegritylivesnomore.

Alivingorganismenduresasastructureinanextraordinaryway,unparalleledexceptverypartiallybysuchthingsasWilliamAshby's(1960)homeostat.Evenagnatthatlastsasastablestructureforonedaycompelsouradmirationmorethananoceanwave,whichmaylast

aslong,andmorethanaspiralgalaxy,whoselifetimeasarecognizablepatternextendstomillionsofyears.Theorganismteetersalwaysonthebrinkofchaos,batteredfromallsidesbystructure-destroyingforces.Theconceptthathelpsusmakesenseofthisactive"keeping"isfeedback.Suchamodeofenduringrequiresanametodistinguishitfrom

theenduringoftheeternalhillsandofthespiralgalaxies:Letusacceptthestandardbiologicalidiomandcallitsurviving.

Surviving,then,istheonegoalthatunifiesalmostalloftheother,subsidiarygoal-seekingmechanismsinalivingthing.Survivaliswhattheinternalhomeostatthatregulatesbloodsugaristherefor;survivalistheultimategoalalsooftheexternalfeedbackloopsbywhichtheanimaltracksitspreyoreludesthosethatwouldpreyuponit.

Functions

''Function"isatermevenmorewidelyemployedbywritersonteleologythan"goal,"foreventhosewhorejectthegoaltheoryofteleologyconcernthemselveswiththemeaningandjustificationoffunctionascriptions.Whatdowemean,forexample,bysayingthatthefunctionoftheheartistopumpthebloodthroughtheveinsandarteries;andhowcanwejustifysinglingoutthatactivityoftheheartwhilewepassoverothers,suchasmakingthumpingnoisesandpreventingtheleftlungfromtouchingthefrontoftheribcage?

Thestandardcyberneticanalysisoffunctionascriptionsisanexplicationinthefullsenseoftheword:bothanunpackingofthemeaningoftheconceptoffunctionasithasbeengenerallyemployedandacriticalrecommendationforitspureruseinthefuture.Whenweascribeafunctiontoaportionofanorganismoramachine,thisiswhatwedooroughttodo:Wecallattentiontothefactthatthecontainingsystemtendstomaintainsomevariablepropertywithinanarrowerrangethanwouldotherwiseobtain,anditdoessobymeansofapeculiarsortofpatternofcausalconnections,namely,negativefeedback.This"keeping"oftheprotectedpropertyistobecalledthegoalofthecausallooporoftheregulator,andonlythosethingsandprocessesthatcontributetothenormaloperationoftheloop(whoseremovalwouldimpairorhaltit)havefunctionswithrespecttothat

goal.Thefunctionofamemberofafeedbackloopissimplywhatthepartcontributes(notbyhappenstancebutintheregularcausalchain)towardthegoalembodiedintheloop.

However,anacceptabletheoryoffunctionascriptionsmustestablishsomecontinuitybetweenitsowntechnicalexplicationoffunctionalityandearlier,moreintuitiveusages.Theconceptof

negativefeedbackhasarelativelyshorthistory,whereasbiologistsatleastasearlyasAristotlehaveascribedgoalsandfunctionstolivingthingsandtheirparts.How,then,canacybernetictheoryclaimtoprovideananalysisoffunctionalityasithasbeenusedtraditionallyinbiology?Isubmitthattheconceptofsurvivalprovidesthebridgebetweenthetraditionalandthecyberneticalusesofgoalandfunction.Itispossible,evenforonewhodoesnotincludenegativefeedbackinhisstockofconcepts,torecognizeactivesurviving,nomatterhowuntechnicallydiscerned,assomethingthatdistinguisheslivingthingsfromdeadmattergenerallyandtoassignfunctionsontheprinciplethatthefunctionofapartisitscontributiontothesurvivaloftheorganism.Andwehaveseenhowsurvivingcanbeunderstoodmoreexactlyintermsoftheactivemaintainingofstructurebymeansofnegativefeedback.

Ihaveanalyzedfunctionascriptionsasaspecialkindofexplanation.Theyenlightenbecausewhenweascribeafunctiontoapartoraprocessweattributetoitscontainingsystemacertainsortofdynamicalstructure,andwelocatethefunctioningpartwithinthisstructure.Inhisdiscussionoffunctionalanalysisingeneral,RobertCummins(1975)callsthisthe"analyticalstrategy"ofexplanation.ChristopherBoorse(1976)suggeststheterm"operationalexplanation."Whenweemploythisstrategyinscienceweexplainthecapacitiesofacontainingsystemintermsofthecapacitiesordispositionsofitspartsandoftheirmodeoforganization.Cummins,aimingatageneralanalysisofallfunctionallanguage,suggeststhatafunctionalanalysisofacomplexsystemwillbemoreorlessapproximateasthe"program"accordingtowhichthepartsactismoreorless"sophisticated''(p.764).Thisanalysisoffunctionalexplanationshowsittobeespeciallywellfittedtotheprogramofatomisticreduction;for,ifwecandemonstratehowtheteleologicalcapacitiesoflivingthingsaresustainedbythesimpledispositionsof

cellsormoleculesactingincertainpatternsoforganization,thenwewillhavesatisfiedthethreeconditionsthatCumminssuggestsmakeforahighdegreeof"explanatoryinterest":Theanalyzingdispositions(e.g.,attractionsandrepulsions,ortendenciestowardchemicalbonding)willcertainlybe''lesssophisticated"thanthegoal-seekingproclivitiestheyaccountfor;theanalyzeddispositionswillbedifferentintypefromthosethatexplainthem(tele-

ologicalvs.simplycausal);andtheorganizationalpattern(feedbackorinterlockingnetworksofmutuallysupportingfeedbackloops)couldbecalledsophisticated.

Inordertoachievegenerality,however,Cumminsmustsacrificeprecision.Theconceptsoforganizationandofsophistication,whicharecentraltohisanalysis,arenecessarilylooselydefined.Whatkindoforganizationofpartscanjustifyourtalkingoffunctions?Willanytypedoprovidedonlythatitissophisticated?Andwhatshallwemeanbysophistication,beyondmerecomplexity?

Consider,forexample,theprotoncycleforthenucleosynthesisofhelium-4.Hereisaprocessofconsiderablecomplexity,andofaninterestingpatternaswell,becausethesequenceofcausalinteractionscanbediagrammedasacycle.Theindividuallinksinthiscycleinvolvesimpleattractiveandrepulsiveforces,yetthemechanismpartiallyaccountsforthepresenceintheuniverseofanabundantelement.Thecycleiscertainlymorecomplexthanthesimpleprocessesitincorporates,soitcouldbecalledmoresophisticated.Yetthenuclearprocessesthatsupportitdonotmeritteleologicallanguage.Totakeanotherexample,supposethatsomeaccidentalrewiringofthetemperaturehomeostatofawarmbloodedanimalturnsthatsubsystemintoapositivefeedbackloop,sothatdeviationsfromthenormaltemperaturerangeareabettedratherthancounteracted.Wecouldnowexplainthecapacityofthisorganismtogenerateincreasinglyhigherbodytemperatures,togointoconvulsionsandeventuallytodestroyitselfintermsoftheorganizationalpatternofpositivefeedbackandthesimplephysicalpropertiesofthecomponentparts.ThisexplanationwouldalsomeetCummins'sthreerequirementsofexplanatoryinterest,becausecapacitiesforsimpleattractionsandrepulsionsarebothdifferentintypefromandlesssophisticatedthanthecapacityforself-destruction,onanyunderstandingoftheterm"sophisticated";andpositive

feedback,Ishouldthink,haspreciselythesamedegreeofsophisticationasnegative,forthetwopatternsareidenticalsaveforareversedsigninamathematicalfunctionatonepointintheloop.

IdonotclaimbytheseexamplestorefuteCummins'sanalysis;ImerelypointouttheincompletenessofhisprogramandrecommendtheinductiveapproachIhaveadoptedhere.Clearly,functionascriptionsarejustifiedbythefactthatthefunctioning

partsareorganizedintoasystemofsomekind.Butnoteveryorganizedsystemisafunctionalone.Accordingtowhatspecialtypeofpatternmustthepartsbeconnectedinordertoqualifytheircontainingsystemforteleologicallanguage?Proceedinginductivelybycases,andlimitingourselvestonaturalobjects,wehavefoundonesuchpattern,negativefeedback,andanaturalextensionofit,anetworkofmutuallysupportingfeedbackloops.Thispatternanditsextensionexplicate,respectively,thecapacityofanorganizedsystemtoseekgoalsandthecapacityofanorganismtosurvive.

Arethereothertypesoforganizationthatwouldalsojustifyfunctionascriptions?AndwouldasystematicstudyofthesetypesallowustofleshoutCummins'sconceptofsophistication?Possiblyso,butIsubmitthatthetwocyberneticpatternssofardiscussedaregeneralenoughtocoverthescientificallyinterestingcases.Supplementedbytheconceptofselectiontobediscussedinchapter6,theywillproveadequatetomakesenseofalltheusageseventheweaklymetaphoricalonesoffunctionallanguagefornaturalsystems.

Whetherornotwehaveexhaustedthevarietyoforganizationalpatternsthatcanjustifyfunctionalexplanations,wehavestudiedenoughtomakeatentative,yetconfident,replytotheskepticalquestionsraisedintheopeningparagraphsofchapter4abouttheatomistprogramforreducingteleology.Eveniftheconceptsoffeedbackandofnetworksoffeedbackloopsdonotaccommodatethewholerangeofteleologicalsystems,theymayneverthelessbetakenastypicaloftheanalyticalconceptsproducedbytheclassofwhatWoodfield(1976)callsinternalisttheories.Andwehaveseenbothhowsome(atleast)ofourteleologicaldescriptionsandexplanationsmaybeexplicatedintermsofcyberneticconceptsandhowsomeoftheseconceptsmayinturnbereductivelyexplicatedbyreferencetomechanicalpartsandtheirinteractions.WilliamWimsatt(1971)andChristopherBoorse(1976)havewarnedthattheconceptsonwhich

thecyberneticanalysisofteleologyrestsmightnotbeobjectivepropertiesofnaturalthingsbutmerelyprojectionsofhumanintentionality.Ifso,thecybernetictheorywouldnotbeareductiveanalysis,andthephysicalistprogramforunderstandinghumanintentionalityintermsofcyberneticconceptswouldbetwistedintoaviciouscircle.However,astheprecedingargumentsshow,thosedoubtsmaynowbelaidtorest.

Applications

Next,letusinquirewhetherthenarrowlyfocusedanalysisofteleologyIhavepresentedabovecanshedanylightuponfourquestionsmuchdebatedbyphilosopherswhotakeaninterestintheuseofteleologicalconceptsinbothhumanandnonhumancontexts.

TypesOrTokens?

Doweascribefunctionsprimarilytokindsofthingsorprimarilytoindividuals?BerentEnc(1979,p.361)explicitlyrequiresthatfunctionsbeascribedtoindividualpartsofindividualorganismsonlysecondarily,thatis,onlyonthebasisofwhatpartsofthatsortnormallydoinorganismsofthatkind.Andotherphilosophers,Wright(1973),forexample,alsoplaceprimaryemphasisonsuchthingsasthefunctionofheartsingeneralinvertebratesingeneral.Obviously,thisapproachtofunctionalitycomfortablyaccommodatesbiology'straditionalconcernwithnaturalkinds.Incontrast,thecyberneticanalysisIhavebeendefendingrequiresustoassignfunctionsinthefirstplacetoindividualpartsofparticularorganismsormachinesandtobuildupinductivelytokindsofpartsandkindsofsystemsonlysecondarily,onlywhensuchgeneralizationsarepossible.Suppose,tofetchanexamplefromafar,thatanimprobableinterventionduringthedevelopmentofachickembryocausesthetissuethatwouldotherwisedevelopintoabeatingheartpassivelytoallowthepassageofblood,andthetissuethatwouldhavedevelopedintotheaortanowcontractsandexpandsrhythmically,pumpingwellenoughtokeepthechickaliveforadayortwo.Acyberneticanalysisofthisaberrantcasewouldassigntheblood-pumpingfunctiontothisuniqueexpressionoftheaortalgenes.Itsinductivecharacterindicatesthesuperiorityofthecyberneticapproach,forhowcouldoneassignfunctionstoatypeofthingpriortodiscoveringfunctionsofindividualtokensofthetype?

Necessity.

Inwhatsense,ifany,canwesaythatafunctionalpartisnecessaryforthegoal-seekingbehaviorofthecontainingmachinery?AccordingtoCarlHempel's(1965)analysisofthesyllogisticformofafunctionalexplanation,onepremiseconcernsthenecessityofthefunctionalpartfortheproperworkingofthesystem.Enc,too,impliesnecessityofasortwhenhestipu-

latesthat"onlythekindofthingXiswilldoYinallW's"(1979,p.349).Certainly,thesenseof"necessary"here,andasotherphilosophersuseit,isnotastrongone,becauseartificialheartsorkidneyscouldinprincipleperformthefunctionsofthoseorgansineverylivingorganism.Incallingafunctionalpartnecessary,wesuggestnotthatitcanhavenosubstitutesbutonlythattheallegedlynecessarypartmakesacertaincausalcontributiontothegoal-seekingactivityandthatnootherthinginfactmakesthatcontributiontothissystem.Thetheoreticalmodelofthesystem,fromwhichaloneweobtainourassertionsofcounter-factualconditionals,showsthatifthepartdidnotperformitsfunctiontheteleologicalactivitywouldnotoccur.Butnecessity,inthissense,isnotanecessaryconditionofagivenpart'shavingafunction,becausemanyfunctionalpartsoperateinparallel.Onthisunderstandingof''necessary,"neitherasinglekidneynorasingleisletcellinthepancreaswouldbenecessaryfortheproperoperatingofitscontaininghomeostat,forintheabsenceofthatorganorcellthefunctionwouldbeperformedbytheotherkidneyortheotherisletcells.Eachmakesthesamekindofcontributiontothissystem,andthatkindofcontributionisnecessary.Removingalloftheparallelpartswouldhalttheoperationoftheloop,andremovingasizablefractionwouldseriouslyimpairit.Thusthepairofkidneysisnecessaryinthissenseforthepurifyingoftheblood,andtheabsenceofapancreaswithoutsubstitutionwouldindeedentailtheendoftheblood-sugarhomeostasis.Thevariousconsequencesofwhatanypartofamechanismdoescanbereadoutofitstheoreticalmodel;someconsequencescontributetotheregulatingactivityofthecontainingfeedbacklooportothestabilityofasurvivingnetworkofloops;somedonot.Theformerarethefunctionsofthoseparts.

SystematicAssignmentofFunctions.

Canwecodifythewayweidentifyfunctions?Wehaveestablishedthatfeedbackloopsexhibitteleologyinitsmostrudimentaryformand

thatmutuallysupportivenetworksofthemarefullyteleologicalsystems,mechanismsthatactivelysurvive.And,speakingloosely,wehavesaidthatafunctionissomesortofcontributiontothisgoal-seekingactivity.Itremainstostipulatemorepreciselyhowwearetoassignfunctionsinateleologicalsystem,oncewehaveidentifieditsgoal.Irecommendthefollowingfourrules,justone

ofwhichrequiresextensivejustification,forascribingfunctionstothepartsofagoal-seekingsystem.

1.Becausefunctionsareeffectsofcausalactivity,onlyacausalagentthatis,amaterialcomponentofthemachineororganismcanhaveafunction.

2.Thepartmustbepresentinthesystemandparticipateinitsactivityasifbydesign;thatis,thepart'spresenceinandcausalinteractionswiththerestofthesystemmustbeinacertainsensearbitraryorspecial,notmerelyanincidentaleffectofsomeotherfunctioningpart,nottheresultofmerephysicalnecessityinherentinthecontrolledsystemitself.ThispointismaderepeatedlybyGeorgeC.Williamsinhissuggestiveanalysisofbiologicaladaptation(1966,pp.1113,261,e.g.),andStevenJ.GouldandRichardC.Lewontin(1979)havesoundedasimilarwarning,withespecialvividness.InWilliams'sexample,eventhoughaflyingfish'ssurvivaldependsonitsreturningtothewaterafterabriefflightthroughtheair,andthoughthevariouspartsofitsbodycontributetothisnecessaryprocessbytheirgravitationalattractiontowardtheearth,wedonotsaythatthedrawingdownwardisafunctionofthebodyasawholeorofitspartsactinginparallel.Nospecialarbitrarymechanismisinvolvedhere:Whatgoesupmustcomedown.Allthespecial,functionalmechanismsofthefishlaborintheoppositedirection,keepingtheorganismaloftforawhile.

Afunctionalpartmustbeagratuitousadditiontothesystem,superimposeduponmerephysicalnecessity.Itsarbitrarinesscanberecognizedwiththeaidofthecriterionofindependentdisconnectability,asthefollowingexamplesindicate.Accordingtothetheoreticalmodel,theregulatingsubsystemcaninprinciplebedisconnectedfromtherestofthefeedbackloopbyremovingmaterialparts,insuchawaythatanintegral,controllablesystemremains.The

subsystemis,therefore,aphysicallycontingentadditiontothesystemitcontrols.

3.Thefunctionofapartissomethingthatitdoes,orcausestooccur,thatisnecessaryasdefinedaboveeitherindividually,aswithsingularparts,orinsum,aswiththosethatoperateinparallelfortheregulatingactivityofthefeedbacklooporfortheactivesurvivingoftheorganism.

4.Insufficientlycomplexstructures,goalsandfunctionsmaybearrangedinhierarchies.Thegoal-seekingorgoal-achieving

activityofafeedbackloopwillnormallyhaveafurther,functionaleffectinitscontainingorganismand,asWilliams(1966)pointsout,theloop'sowngoalmaybeconnectedwiththesurvivingoftheorganismonlyincidentallyorstatistically,withrespecttoprevailingconditions.InWilliams'sexample(p.269),atimingmechanisminafruitflyadjuststheinsect'sactivitiestodiurnalvariationsinillumination;thus,thegoalofthisregulatingmechanismisthematchingofactivitytothecycleofdayandnight.Buttheactivitycontributestotheorganism'ssurvivalbecause,undernormalconditions,variationsinilluminationcorrelatewellwithvariationsinhumidity,andthelatterenvironmentalfactor,ratherthantheamountoflight,hasadirectbearingontheorganism'sproperfunctioning.Thefunctionofthismechanism,theadaptingofactivitytohumiditylevel,differsfromitsgoal.Itisnotevenadirectcausalconsequenceofachievingthegoalbutamerelystatisticalcorrelateofit,becausechangesinhumidityandlightintensityareproducedbyacommoncausalprocess.

Thereisanundeniabledegreeofarbitrarinessintheserulesforascribingfunctions.Forexample,whetherornotacomponentofafeedbackloophasafunctiondependsinpartonwhetheritspresenceisanarbitraryorphysicallycontingentadditiontothecontrolledsystem,andthatinturndependsonwherewechoosetodrawthelinebetweentheregulatorandthecontrolledsystem.Considerathermostaticallyregulatedhouse.Thecausalchaininthisinstancehasenoughlinksinitforustomakethisdivisionatanyofseveralpoints.Wemaychoosetoconsiderthefurnacetobepartofthesensorcontrollerandtheregulatedsystemtobesimplythebuildingitselfwithitsemptyrooms,heatedbythesunandcooledbyconductionthroughthewallsandwindows.Onthatchoice,thefurnaceistherebydesignandhasafunctionintheloop.Orwemayconsiderthefurnacetobepartofthefurnishingsofthehouseandsoamemberofthe

controlledsystem.Inthatcaseitisnotanarbitraryadditiontothissystemand,hence,notacandidateforafunctionascription.

Althoughtheatomistreductionprogramcannottolerateanelementofconventionalityorsubjectivityinthedrawingofaboundarybetweenteleologicalandnonteleologicalsystems,itcanquitecomfortablyaccommodateacertainamountofarbitrarychoiceintheassigningoffunctionstoparts.Whatmatters

forreductiveatomismisthatathing'sbeingagoal-seekingsystembeentirelyanobjectivepropertyofthesystemitself,withnotraceofhumanintentionalitybeingimpresseduponitfromoutside.Oncethispointismadeclear,itdoesnotgreatlymatterhowwecondensethecompletecausalstorythatmightbetoldabouttheoperationofthefeedbackloop,whetherwepicturetheinteractionsinintricatedetailorpaintwithabroaderbrush,orjustwhichlinkinthecausalchainwenameasthecontrollingactionofthesensorcontroller.Andwheredistinctionsmatterthecyberneticanalysisdoesnotfailus.Inthelightitshedswecandistinguishthefunctionalcontributionofthescrewsthatholdthebimetalstripinitsplaceinathermostatfromtheordinary,nonfunctionalparticipationofthewindowsthroughwhichheatescapes;wecanseethatthegudgeonsthatholdtherudderinplaceonthetransomofanautomaticallysteeredsailboathaveafunction,whereasthetransomitself,beingpartofthecontrolledsystem,doesnot;andwefindthattheisletcellsandtheconnectivetissueofthepancreas,aswellastheinsulinmoleculesitproduces,playfunctionalrolesintheblood-sugarhomeostat,whereastheglucose,partoftheregulatedsystem,doesnot(althoughglucosedoesindeedfunctioninotherfeedbackloops).

Generalizing.

Canweproduceageneralanalysisofteleologicallanguage,speakingwithonevoiceabouttheapplicationofteleologicalconceptstohumanbeings,totheirartifacts,andtonaturalobjects?ThisisaquestionIhavesetoutsidetheboundsofthisbook,butitisappropriatetoaskatthispointwhethertheinductivestrategyIhaveadoptedcanmakeanycontributiontothismoregeneralphilosophicalinvestigation.

Inthemostgeneralcase,whenweaskwhatapartinsomeartifactistherefor,theanswercanbeobtainedonlyfromitsdesigner.Thefunctionofthesmallhammerthathangsfromacertainsortoffire

alarmmaybeguessedbyanyoneendowedwithamodestacquaintancewithhumanaffairsorwiththeabilitytoreadthemessageinscribedupontheappliance,butitcannotbestrictlyinferredfromaknowledgeonlyofthecausalconnectionsinternaltothedevice.Thefunctionofthehammerisdeterminedbywhatthedesignerandusersoffirealarmsintendforit.However,inothercases,theintentionsofthedesignerdonotsettletheissue.Ifsomeineptfabricatorassembledathermostatbyin-

advertence,intendingtomakesomeothersortofcontrivance,allhisprotestationstothecontrarywouldnotoverruleourclaim,basedonananalysisofhowthedeviceoperatesinfact,thatthefunctionoftherelayswitchistoturnthefurnaceonandoffandthefunctionofthebimetallicstripistosensethetemperatureoftheroomaroundit.Wehaveinthecyberneticanalysis,then,awayofpinningdownforsomeartifactsandforallbiologicalsystemswhatitmeansforaparttoconfersomegooduponitscontainingsystem,tohavewhatPeterAchinstein(1977)callsaservicefunction.Theserviceorthegoodconferredis,inthetypeofmechanismthatcanbesaidtosurvive,acontributiontotheinternalprocessesthatconstitutesurviving,themaintainingofstructurebymeansofnegativefeedback.

SixTeleology:SelectionismTheselectionistanalysis,likethecybernetical,attemptstostretchthecomplexofteleologicalconceptsfarenoughtocoverbothhumanpurposiveness,thesourceofouressentialparadigms,andexamplesofrudimentarymeans-endconnectionsinsimplebiologicalsystems.Wehaveseenthatthecybernetictheoryidentifiesteleologyatthehumanendofthescalewithgoalseeking,ofwhichthehelmsmanisaprimeexample,andattheotherwithhomeostasis,suchastheregulationoftemperature.Theselectionisttheory,ontheotherhand,pointsattheupperendofthescaletothesortofconscious,purposiveselectingthatgoesoninhumanproblemsolvingandothercreativeactivityandatthelowerendtotheDarwinianprocessofnaturalselection.Ontheissueofreduction,thetwotheoriespullinoppositedirections.Thecybernetictheorydirectsusinwardanddownward,findingthesourceofteleologyinsidetheindividualmechanism,intheworkingsofitsinnerparts.Theselectionisttheory,ontheotherhand,seemsto"reduce"upward,findingthesourceofteleologyinmoreinclusive,higher-levelsys-

tems,intheselectingagentanditscriterion.Letustrytotestthevalueoftheselectionisttheoryasananalyticaltool.Wemustbecareful,however,nottostretchtheconceptofselectionfartherthanitcango,nottomistakeforconceptualunificationwhatisinfactmerelyanattractivebutfalseanalogy.LetDarwin'sownexample,aflightoffancytheliteralsenseofwhichheexplicitlydisavows,putusonourguard:

Itmaymetaphoricallybesaidthatnaturalselectionisdailyandhourlyscrutinising,throughouttheworld,theslightestvariations;rejectingthosethatarebad,preservingandaddingupallthataregood;silentlyandinsensiblyworking,wheneverandwhereveropportunityoffers,attheimprovementofeachorganicbeinginrelationtoitsorganicandinorganicconditionsoflife.[DARWIN1859,1872,chap.4,para.6;emphasishis]

Canteleologicaldescriptionsandfunctionalassignmentsexplainwhyafunctioningpartofanaturalsystemisthere?Canthey,asWimsatt(1972)andWright(1973)suggest,tellusanythingabouttheoriginsofteleologicalstructures?Thesephilosophersproposetoconnectteleologywithtwoconceptsthatareascharacteristicofbiologicalthinkingashomeostasis,namely,naturalselectionandadaptation.Todemonstratetheinitialattractivenessoftheselectionisttheoryofteleology,Ishallshowthat,althoughthecybernetictheoryiscapableofaccommodatingsomeofthebiologicalapplicationsoftheprimafacieteleologicalconceptofadaptation,itfailstomakesenseofothers,equallyfirmlyentrenchedinbiologicalthinking.Inordertodealwiththeseapplicationsweshallhavetogivetheselectionisttheoryahearing.

Theconceptofnaturalselectioncontributestoteleologicaldescriptionsoflivingthingsintwomajorways:Itgivesusareasontointerpretsomefactsasevidenceoffunctionaldesign,anditleadsustothinkof''adapting"asaprocessthatoccursovermanygenerationsin

alineofdescent.Letusfirstexaminesomesymptomsoffunctionality.

Weusuallydonotascribefunctionstothingsbyfollowingformalrules;wegetalongquitesatisfactorilywithintuitiverulesofthumb,whichareconsiderablylessformalandpossiblylesscontroversialthantherulesIhaveproposedinchapter5.Inmostpracticalinstanceswearecontentwithaplausiblecase.

Williams,too,forallhiscautiousskepticismaboutfunctionascriptions,employspartialbutsuggestivecluesinhissearchforadaptations.Twosortsnormallycountasprimafacieevidenceoffunctionality:Thefirstconnectswithcybernetics,andthesecondwithselection.

Thefirstandmoreobviouskindofclueisbehaviorthatseemstohappeninresponsetoachallengefromoutsideandtobedirectedatmaintainingstabilitywithintheorganism.Whenweseethatfruitfliesadjusttheirperiodsofactivityandinactivitytocorrelatewithdaylightanddarkness,wemayplausiblyspeculatethatthebehaviorisdirectedatsomeproximategoalandsearchforacyberneticstructurethatgeneratestheobservedbehavior.

Thesecondandmoresubtlekindisthepresenceofsomepeculiar,seeminglyarbitrarystructurewithintheorganism.Theeye,forexample,issuchanoddandintricateorganthatitcannotsimplybeanincidentalorextraneousfeatureofitscontainingsystem.Uptothispoint,butnotbeyond,themodernbiologisttreatstheevidencejustasdidWilliamPaley,thechampionofdivinedesign(Williams1966,p.259).Ifasystemistheproductofaconsciousdesigner,thenanyelaboratepartthatmighthavebeenleftoutmusthavecostitsmakersomeeffort.Arationalfabricatorexpendseffortparsimoniously.Therefore,thepartprobablywasputtheretoperformsomefunction,sothatitrepaysitscosttoitsmaker.Themodernbiologistreasonsnontheologically,yettheargumentiscuriouslylikePaley's.Withoutpresumingthatthesystemwasproducedbyconsciousdesign,onestillisabletospeculateaboutcostsandbenefitsinevolutionaryterms.Thecostistheeffortrequiredtomaintainthepurityofageneticlinethroughgenerationsofcopying,despitetendenciestowarddegeneration.Naturalselectiontakestheplaceoftheconsciousdesignerinspeculatingaboutnaturalsystems,andinsteadofapresumptionaboutrationalparsimonyoneadoptsananalogous

principleaboutsweepingouttheerrorsthataccumulateinthegeneticcopyingprocess.AsWilliamssays:"Any[biological]systemwilldegeneratetotheextenttowhichthereisarelaxationofselectionpressureforitsmaintenance"(p.266).Consequently,whenwediscoveranapparentlygratuitousyetintriguinglycomplicatedpartofanorganism,suchasthehumanpinealglandorvermiformappendix,itisreasonabletospeculatethatthestructurecontributessomethingtothehealthandstabilityofthesys-

tem.Theclueisnotinfallible,ofcourse;aftercarefulstudywemayconcludethattheappendixservesnofunctionatall,eventhoughtheorganismfaithfullyconstructsitaccordingtoanancientblueprint.

Besideshelpingustoviewgratuitouscomplexityasacluetofunctionality,theconceptofnaturalselectionalsosuggestsapeculiarlyevolutionarysenseoftheterm"adaptation."Williams'suse,Ibelieve,istypicalofthecarefulemploymentofthisconceptbyevolutionarybiologists.Hedistinguishestwosorts,facultativeandobligateadaptation(e.g.,1966,p.81).Intheformer,theorganismrespondstovaryingextentsandinseveralwaystoenvironmentalstimulisoastocountertheharmtheywouldotherwisedo.Thethickeningoftheskininplacesthatreceiverepeatedandfrequentfrictionillustratessuchafacultativeresponse;itisanadaptationintheprimarysenseoftheterm,anactivemobilizingoftheinnerprocessesofthesystemtomeetsomeexternalthreatandsotopreservethestructureoftheorganism.Inthisprocessthereare,accordingtoWilliams,"sensingandcontrolmechanismswherebythenatureoftheresponsecanbeadaptivelyadjustedtotheecologicalenvironment"(p.82).Thecyberneticanalysisofteleologyintermsoffeedbackhasanobviousapplicationhere.Butbiologistsalsorecognizefixedorobligateadaptations,anexampleofwhichisthethickeningoftheskinonthesolesofthefeet,whichbeginsalreadyinutero(p.79).Howisitpossibletoemployasingletermbothforspeakingaboutthegeneticallyfixedcharactersoforganismsandforthosetheydevelopinresponsetotheexigenciesofliving?Thetheoryofevolutionbynaturalselectionprovidestheframeworkthatseemstojustifythisunification.Thecallusonafarmer'shanddevelopsinresponsetopressurefromthehandleofthehoe;similarly,thethickenedskinnowfoundonthesolesofhumaninfantsdevelopedasourancestralspeciesrespondedtothepressureofselectiveforces.Clearly,theterm''adaptation"isusedindifferentsenses.Ishallcallthemcybernetical

adaptationandevolutionaryadaptation.Thetheoryofnaturalselectionsuggeststhattheconceptscanbetreatedasonebyreasonofananalogybetweenresponsivechangeswithinanindividualorganismandmutationsinalineofdescent.

Attractiveastheanalogymaybebetweentheresponseofaspeciestoselectionpressureandtheresponseofanindividual

organismtovariousenvironmentalopportunitiesandthreats,wedonotneedselectiontojustifyourascribingfunctionstomanyobligateadaptations.EvenifweknewnothingofDarwin'saccomplishment,wewouldstillbeabletodeterminethefunctionofthevertebrateretinaorofthewalrus'sblubberbyfollowingtheprescriptionofthecybernetictheory:Wewouldsearchforthecontributionthestructuremakestothesurvivaloftheindividualorganismthatbearsit.Thereisaconsiderableareaofagreement,evenofredundancy,therefore,inwhatwelearnfromananalysisoffunctionsintermsofadaptations,intheprimarysenseofthatterm,andwhatwelearnfromananalysisbasedonthenotionthatspeciesadapttotheexigenciesofnaturalselection.Almostanythingthatpromotesthesurvivalofanindividualorganismalsopromotesthespreadingofcopiesofitsgenesamongthepopulation.

Iftheareascoveredbythecyberneticalandevolutionaryunderstandingsofadaptationcoincidedexactly,anatomistcouldfairlychoosetheformer,onthegroundsthatitfitsbetterthanselectionismintothereductionprogramofatomism.Butthetwoareasdonotwhollyoverlap,asthefollowingexamplesdemonstrate;therefore,ourchoicebetweenthetwotheoriescannotbemademerelyaccordingtopreferencefortheatomistprogram.

Somecasesofwhatisconventionallycalledadaptationfallwithinthecircleofselectionismalone.AllthecasesofthistypethatIamawareofconsistofthestructuresandstrategiesofreproduction,andeverysuchstructurebelongstothistype.Cyberneticaladaptationsare,ofcourse,abundantwithinthereproductiveprocess;forexample,themechanismsthatregulatethelevelsofsexhormonesintheestruscycle.Butletusinquireaboutthefunctionsoftheestruscycleitself.Tothisquestionthecybernetictheoryrespondswithsilence,atbest.Thecycledoesnotcontributetotheactive,delicatebalancebywhichtheorganismsurvives.Thisfinelytooledsubmechanism,thoughit

fullysatisfiestherulethatafunctionalpartmustbeagratuitousadditiontotheorganism,hasjustnofunctiondiscoverablebyacyberneticalanalysis.

Infact,thecybernetictheoryoffunctionalitytreatsreproductivestructuresevenlesshospitablythanthisexamplesuggests:Itpronouncesthemtobemaladaptive,dysfunctional.Thinkoftheenormousamountofeffortdevotedbyanestingpairofwood

warblerstotheraisingofseveralbroodseachsummer,effortthatmighthavebeenspentinbuildinguptheirownbodiesinpreparationforthefallmigration.ThisdysfunctionalitycanbeseenevenmorereadilyinthePacificsalmon,whosebodyvirtuallydisassemblesitselftoproduceenergyforitsmightyefforttoreachthespawningbedsupstream,ajourneythatendsindeathfortheorganism(Williams1966,p.174).OnlyinanevolutionarysenseofadaptationcouldWilliamscallsuchanextremesubordinationofindividualsurvivaltoreproduction''clearlyadaptive":Acyberneticalanalysiswoulddictatetheoppositejudgment.

Hereisacrisisofsortswhosemagnituderemainstobeassessed.WehavefoundaclassofstructurestowhichteleologicallanguagehasbeenappliedsincebeforeDarwin'sdayandofwhichthecybernetictheorycanmakenosense.Hasthecontenderthatwastohavebeenthechampionofatomisticreductionismbeenunhorsed?

Letusbeclearastothepreciselocationofthecontest.ItisnotbeingconductedwithinthelaboratoriesoftheBiologicalSciencesCenter;theneo-Darwiniantheorystillseemscapableofexplainingtheoriginsofalltheseallegedlyteleologicalsystems.Rather,thebattleisaskirmishbetweenreductionismandanti-reductionismforcontroloftheterritoryofhumandesires,beliefs,andgoals.Ifcyberneticalconceptscanbereducedatomisticallyandiftheteleologyofmachinesandsimplelivingsystemscanbeunderstoodincyberneticalterms,thenthecaseforthemechanisticreductionofhumanintentionality,thoughnotofcourseproved,isrendereddecidedlyplausible.Butiftheteleologyofanaturalobjectcanbeunderstoodonlyintermsofstilllargerteleologicalsystemsthatencloseit,thenthepossibilityofareductiveexplicationintermsofthesystem'spartsseemstobeblocked.Wewouldhavenoparadigmonwhichtomodelourreductionofhumanteleology,andthatundeniablyrealandcharacteristicpropertyofhumanlifemightturnouttobeirreducible.

Havingstruckthisblockintheatomistroad,wecanchooseamongthreepossiblepaths.Wecantrytoproduceacyberneticalanalysisevenofthemechanismofnaturalselection;wecanrevampourexplicationoffunctionalityunivocallyalongselectionistlines;orwecandecidethatteleologicaltermsasthey

areusedinbiologydivideirreconcilablyintotwocamps,onegroupedaroundcyberneticaladaptationandtheotheraroundevolutionary.

NaturalSelectionasCyberneticMechanism

Thefirstoption,thespeculationthatnaturalselectionmayoperateasakindofnegativefeedbackprocess,isproposedbyMichaelRuse(1973)andbyJ.L.Mackie(1974)andisdismissedwithabriefmentionbyCummins(1975).Aswehavenotedabove,theterm"feedback"iswidelyemployedinavarietyofratherloosesenses,mostofwhichareonlymarginallyrelatedtotheconceptwhoseexplicationandteleologicalinterpretationIhaveattemptedtoproduce.Certainlysomeofthelooser,nonteleologicalsensesofthetermmayfitthecaseofnaturalselection.ButRusetakestheconjectureseriouslyenoughtodiscussasampleevolutionarymechanismandtoarguethatitqualifiesasagoal-directedsystemunderNagel's(1961)explicationoffeedback.ThemechanismRusediscussesistheevolutionaryprocessbywhichthenumberofeggslaidbyatypicalnestingploverismaintainedatastablevalueoffour,forthegreatmajorityoffemalesinapopulation.Fouristheoptimalnumberforplovers,becausethreeorfeweryoungistoosmallanumbertoreplacebirdslostthroughpredationanddisease,andfledglingsraisedinanestoffiveormoreovertaxtheirparents'capacitytocareforthem.Onthefaceofit,then,thisprocesshastheappearanceofa"keeping"mechanismthatmaintainsasysteminabeneficialgoalstate.Letusseehowthisprocessworks,describingitasnearlyaspossibleinaformcongenialtotheanalysisoffeedbackIhavepresentedabove.

Thechangesweshalltrytoviewascyberneticaladaptationsoccurnotinindividualbirdsbutinapopulationoverseveralgenerations.Followingthemodelofouranalysisoffeedback,letusdistinguishtwosubgroupsinthesystem,twodistinctlinesofdescent,oneof

whichistobetheregulatedsystemandtheothertheregulator.Tendenciestodeviatefromtheoptimalclutchsizewillenteraportionofthetotalpopulationsofploversbecauseofaccidentalmutationsthatdisposethebirdsthatcarrythenovelgenestolay,letussay,fiveeggsor,inothermutations,three.

Here,then,isanexogenousdisturbanceofthesystem,a"force"thattendstopushitawayfromitsgoalstate.Becausealllineageswithinthepopulationcompeteforlimitedsuppliesoffood,nestingsites,andotherresources,avariationinonelineagethataffectsthecompetitivekeennessofitsmemberswillhaveacausaleffectonthemembersoftheotherlineages.Inresponse,these"otherbirdsdothingswhichtheywouldnothavedonehadtheoriginaldisruption(thatis,mutation)notoccurred"(Ruse1973,p.180).Clearly,thisanalysisofthemechanismleadsustotrytofititintothefeedbackpatternbyidentifyingthelineageinwhichthemutationoccursastheprotectedsystemS,theotherbirdsastheregulatingsubsystemC,andthecompetitionbetweenthetwoasthecausallinkbywhichCsensestheoriginaldisturbance.Butwecanpushtheplover'sstorynofartherintothismold.The"correcting''connection,bywhichtheotherbirdsaresupposedtoreactuponandcounteracttheoriginaldeviation,consistsofmoreofthesamecompetition.This"correction"isnot,therefore,anindependentlydisconnectablecausalprocess;itis,infact,identicaltothe''sensing."Worsestill,theeffectofthis"adaptation"bytheputativeregulatoronthesystemitissupposedtoregulatebearslittleresemblancetoaprotectivecorrectingormaintainingofsomebeneficialstateoftheregulatedsystem.Indeed,theactivityoftheputativeregulator,itsresponsetotheinitialdisturbance,doesnothingwhatevertorestorethedeviantlineagetothe"goalstate"ofproducingfour-memberclutches.Rather,theotherbirds(andletusaddthecreatureswhopreyuponplovers,andotherspecieswhocompetewiththemforresources)respondbyoutperformingthebearersofthemutantgeneintheracetoreproduceandtoappropriatefoodandterritory,drivingthatlineagetowardlowernumbersinthepopulationandeventuallytoextinction.

Thissimplebutrepresentativeexampleofhownaturalselectionworksisjustnotcomplexenoughtoqualifyasateleologicalprocess

inthecyberneticsense.Neitherthespeciesitselfnorthespeciestakentogetherwithitsenvironmentalhazardsadmitsofanalysisintotwosubsystems,oneofwhichregulatestheotheraccordingtothemodelofnegativefeedback.Aspeciesorspecies-environmentcomplexisnotamechanismthatadaptsinthewaythatthepancreasadaptstoanincreasedlevelofglucosein

theblood.Theconjecturethatnaturalselectioncanbesubsumedunderacyberneticalanalysisdoesnotseempromising.1

Letusconsider,then,thesecondoption,writingaunivocalexplicationofteleologicalconceptsalongentirelynewlines,givingtheconceptofselectionratherthanthatofgoalthepivotalposition.

UnivocalSelectionism

Intheirindependentand,forourpurposes,highlyconsonantanalysesoffunctionascriptionsandfunctionalexplanations,WilliamC.Wimsatt(1972)andLarryWright(1973)aimatnothinglessthanacompleteaccountofallusesofteleologicalterms.Thus,theyrightlydevotetheirattentionlargelytothecontextofhumanpurposiveness.However,whentheydiscusstheuseoffunctiontermsinbiologytheyattempttoestablishconnectionswiththetheoryofevolutionbynaturalselection.Inthefollowingdiscussionoftheirtwoversionsofselectionism,Ishallconcentrateontheirtreatmentofsimplebiologicalsystems,inquiringhowtheseversionsofselectionismfareincomparisonwiththecyberneticalapproach.

Accordingtotheselectionistconjecture,inascribingafunctiontoamemberofasystemweimplyaspecialsortofexplanation(Wimsatt1972,p.67;Wright1973,p.154).ThatmuchmaybesaidalsoofthecybernetictheoryasIhaveinterpretedit.But,whereasthelatterviewsafunctionascriptionasanimplicitassertionaboutthemodeoforganizationofthecontainingsystemandofthepart'splaceinit,Wright'stheoryinterpretsafunctionascriptionasaclaimabouttheoriginsofthepartabouthow,orwhy,orforwhatreasonitcametooccupyitspresentplace."SayingthatthefunctionofXisZ,"Wrightsuggests,"issayingatleastthatXistherebecauseitdoesZ."Inthisformulationtheterm"because"has''anetiologicalforce"(1973,p.157);itcallsourattentiontothecausaloriginsofX.ThedoingofZby

X

1/Thefailureofonesupposedexampledoesnot,ofcourse,refutetheconjecture.Ireferthereadertomy1984essayforadditionalandequallyunsuccessfulattemptstoconfirmit.Ibelieve,however,thatthefailureoftheseexamplesrobstheconjectureinterestingthoughitisofwhateverinitialplausibilityitmayhavehad.

figuresinthestorywemusttellabouthowXcame,throughaseriesofcausallyconnectedepisodes,toitspresentsituationinthesystemthatcontainsit.WimsattmakesasimilarclaimbutreferstopastperformancesofZbypossiblyotherthingsthanX:Afunctionascription"implies...thatthepastcontributiontotheendpromotedbyaselectionprocessofsimilarorotherfunctionalentitieshasresulted,viatheselectionprocess,inthepresenceandformofthefunctionalentityinquestion"(1972,p.67).FollowingWright'sprescription,wequerythedesignersofamotoranddiscoverthattheywerenotinterestedingeneratingaflashofbluelightoranyotherelectromagneticwave;theyincludedaswitchinthetotaldesignbecauseitturnsoffthemotor.Itistherebecauseitdoesthat.

Howdothesetwovariationsontheselectionistthemeconnectteleologicalideastonaturalselection?InWright'stheory,therelationisestablishedbymeansoftwousefuldistinctions.First,Wrightdistinguishedtwotypesofetiology.Thefirstisasimplecausalstory,suchastheexplanationthatoxygenispresentinthebloodbecauseitcombineschemicallywithhemoglobin.Thesecondisan"evolutionary-etiological"story,forexample,theassertionthatoxygenisprevalentinthebloodbecauseitproducesenergy(1973,p.160).Second,Wrightdistinguishesbetweentwosensesoftheterm"selection."Whethertheselectionisperformedbyaconscious,deliberatingagentorbyanonconsciousmechanism,wemustdistinguish"merediscrimination,"wherethechoicedoesnotservesomepurposebutisdoneasitwereonawhim,from"consequenceselection,"wherethechoiceismadebyvirtueof''someadvantagethatwouldaccruefrom"theselectedobject.Onlythelatteristeleological.Eithersortofselectingcanbedonebyselectorsofanydegreeofconsciousness.Inthecaseofnonconsciousselectingmechanisms,theteleologicalsortofselectionisdonebyvirtueofanadvantageousconsequenceoftheselectedpart'spresence;thatis,naturalselectionis

consequenceselection:''WhenweexplainthepresenceorexistenceofXbyappealtoaconsequenceZ,...ZmustbeorcreateconditionsconducivetothesurvivalormaintenanceofX"(p.164).

Wimsattexpressessomedoubtsabouttheconnectionbetweennaturalselectionandhisselectionistanalysisoffunctionascrip-

tionsbutsuggestshowabridgemightbebuiltbetweenthem.Hespeculatesthat"'naturalselection'inbiologyand...trialanderrorlearningprocessesjustifytalkofpurposesandteleology"onlyifsomeadditionalconditionissatisfied(1977,p.17).Thisextrafactormaybe"phenotypiccomplexity,"somethinganalogoustothehierarchicalorganizationofgenes,cell,andsomathatwefindinlivingthings(1972,p.17n;1974).

Aselectionprocessisteleological,inWimsatt'sview,ifthecriterionbywhichitdiscriminatescanqualifyasapurpose;andthecriterionwillsoqualifyifitspecifiesapropertyorstatewhoseattainmentispromotedbysomeentityandifthispromoting"help[s]toexplainwhythefunctionalpartispresentandhastheformthatitdoes"(1972,pp.67,70).

Letusapplytheseconjecturestoabiologicalexamplethatthecybernetictheorycannotaccommodate.Considertheconstellationofbasepairsinafirefly'sgenomethat"codesfor"theapparatusbywhichthematinginsectsemitandrecognizetheircharacteristicpatternofflashes.Aswehaveseen,thecybernetictheorypermitsustoattributefunctionstovariouspartswithinthismachinery,relativetogoal-directedmechanismsthatenabletheinsectstoseekeachother,performtheirmatingroutine,andsoon.Butthetheorycanfindnofunctionforthismachineryasaunitwithintheorganism.Theselectionisttheory,ontheotherhand,easilyassignsafunctiontothereproductivesystem.AccordingtoWimsatt'sversion,basepairsverylikethoseinthefireflywehavecaughtinourbottlepromotedtheabilityofthisinsect'sancestorstofindmates;thisfacthelpstoexplainwhytheirdescendentisherewiththesortofgenomeithas.Consequently,thegenesinquestion(andbythesametoken,thesomaticapparatusthatexpressesthem)havethefunctionofpromotingreproduction.Anditiseasytoseethatasimilarlineofreasoningassignsexactlythesamefunction,thissame"ultimategoal

ofgeneticsurvival"(Williams1966,p.221),toeveryfunctioningpartofanorganism.Eventhesurvivalofindividualsisfunctionalonlyinsofarasitpromotestheproliferationofcopiesofthesurvivors'genes,astheself-sacrificingPacificsalmonremindsus.

Theselectionisttheoryhasreceivedaconsiderableamountofcriticalattention.Ishallnotreviewallofthisdiscussionherebut

shallsimplyassessthoseofthetheory'sstrengthsandweaknessesthatbearuponourchiefconcern,theatomistreductionofhumanteleology.

Twoadmissionsmustbemadetothecreditoftheselectionisttheory.First,itgivesusaprincipledwayofattributingafunctiontothereproductivemachineryoflivingthings,somethingthecyberneticalapproachfailstodo,apparentlytoitsdiscredit.Thisappearstobeanimportantachievementforselectionismbecauseself-replicationbymeansofspecializedsubmechanismsisalmostascharacteristicoflifeasissurvivalbycyberneticprocesses.Ourpraiseshouldbemodulated,however,becauseneithertheabilitytoreproducenorthepossessionofapedigreeisalogicallynecessarycharacteristicoflife.Wedonotdenyaplaceonthetreeoflifetoasterilehybrid,andwewouldnothesitatetograftontothetreeanorganismthatappeared,ifitwerepossible,byspontaneousgeneration.Yetthefactremainsthatselectionismmakessenseofreproductivefunctionality,andcyberneticismdoesnot.

Second,theselectionisttheorypaintsaunifiedpictureofbiologicalfunctions,becauseeverycomponentpartofanorganismpromotestheachievementthatstandsatthepinnacleofthehierarchyofmeansandends,thecopyingoftheorganism'sgenesinsubsequentgenerations.Thecyberneticalpictureoffersanarrowerperspective.Accordingtoit,theultimategoalisthesurvivaloftheindividualorganism,letfuturegenerationsstandorfallastheymay.

Third,theselectionistaccountresonatesstronglytocertainparadigmsofhighhumanpurposiveness,namely,thoseinvolvingconscious,deliberativechoosing.Cyberneticismresonatestoadifferentbutequallyattractiveparadigm.

Last,theselectionistapproachaccordswithcertainterminologicalhabitsofbiologists,withregardtogenetical"survival,"asthe

followinglinesfromWilliamsshow:

Thesmallestprotistisanendlesslyintricatemachine,withallpartscontributingharmoniouslytotheultimategoalofgeneticsurvival....Whenabiologistsaysthatasystemisorganized,heshouldmeanorganizedforgeneticsurvivalorforsomesubordinategoalthatultimatelycontributestosuccessfulreproduction.[1966,pp.221,25556]

However,onthedebitsidemustbelistedseveralgravedefects.LetusconsidersomethatarepeculiartoWright'sversionofselectionism,somethatinhereinWimsatt's,andsomethatweakenboth.Fromthefirsttwocategorieswegetsomehintsoftheflexibilityofthebasicconjecture,fromthethirdanindicationofessentialflaws.

First,Wright'sversionattributesfunctionstolivingsystemstoolavishly.Certaincave-dwellingspeciesoffishhavesightlesseyes,yettheyarepresentintheorganismbecausegenerationsagoeyeslikethesecontributedtoancestralvision.Wright'saccountexplicitlyallowsacomponenttohaveZasitsfunctioneventhoughitdoesnotdoZ;hence,thefactthatthelensandthemusclesthatswiveltheeyenolongercontributetothereceivingofvisualsignalsinthefish'sbraindoesnotletusescapefromtheconclusionthatfocusinglightandmovingtheeyearetheirfunctionsstill.Wimsatt'sversionavoidsthisproblembyrequiringapresentcontributionaswellasanancestralone.

Bothversionsdistributefunctionstoostingily,however.Whenamutationoccursthatwouldcountasafunctionunderacyberneticanalysis,theselectionisttheorymustwithholdtheepithetuntilthemutantgenesbecomeestablishedinthegenepoolasaresultofnaturalselection.Selectionismcannotaccommodatespontaneousnovelty.Wrightrecognizesthislimitationbutdoesnotconsiderittobeadefect(1973,p.165).

Wimsatt'sversionacknowledges,asWright'sdoesnot,thatcontinuouschangemayhappenintheevolutionarydevelopmentofafunctionalpart;Wimsattstipulatesthattheputativefunctionofthepartinquestionmusthavebeenperformedintheancestralorganismby"similarorotherfunctionalentities"thatcontributetothesameendasthepresentone(1972,p.67).Thisstipulation,faithfulthoughitbetothebiologicalfacts,raisesintolerabledifficultiesforthetheory.

Accordingtowhatprincipleshallweidentifytheancestralorgansthataresimilar(ornot!)totheentityinquestion?Only,Isubmit,bythefactthattheyperformthesamefunction.Butwhetherornotthesepartsperformfunctionsatallispreciselythepointthatremainstobedecided.Weseemtobelauncheduponaninfiniteregress.

Bothversionsplacetheevolutionaryhistoryofanorganismsquarelyinthecenterofthecomplexoffactsthatjustifiesfunctionascriptions.Butonecanusuallydiscoverthefunctionofan

anatomicalfeaturesimplybyexamininghowthemachineryworkshereandnow.Therefore,anevolutionaryinterpretationentailsaconceptualbreakwithbiologistsofthepast,becausetheyattributedfunctionswithoutsuspectingtheevolutionaryoriginsoflivingthingsand(althoughsomeheldit)withoutemploying,either,abeliefindivineorigins.

BothWright'sandWimsatt'sversionsmustdistinguishbetweenpurposiveandnonpurposiveselectionand,inordertodoso,employconceptsconnotingpurposiveness.AccordingtoWright,evolutionaryselectionispurposiveonlybecause,whenweexplain"thepresenceorexistenceofXbyappealtoaconsequenceZ,theoverridingconsiderationisthatZmustbeorcreateconditionsconducivetothesurvivalormaintenanceofX"(1973,p.164).Theconceptsofsurvivalandmaintenance,orothersverylikethem,arecrucialtothedistinctionWright'sandWimsatt'stheoriesneed.Buthowarewetounderstandthem?Ihaveshownhowtheymaybegivenacyberneticexplication.Wrightoffersusnone.Wimsattspeaksofselectionprocessesthatservea"purpose"or"end"(1972,p.67)andtellsusthatthecriterionofselectionqualifiesasapurposeifapart'shelpingtomeetthecriterion"constitutesateleologicalexplanationofitsexistenceandform"(p.67),andheexplainsfurtherthatateleologicalexplanationisonethatexplains"whythefunctionalentityispresentandhastheformthatitdoes''(p.70).Wimsatt'sattemptseemstocarrynofartherthanWright'stowardunderstandingwhattherightsortofselectionis.Inthisrespect,Isubmit,bothversionssufferincomparisonwiththecybernetictheory,whichdoeshaveaclearsetofcriteriafordistinguishingpurposivemachineryfromnonpurposive.Butmorecanbesaidinfavorofpurposiveselecting,andIshallreturntothetopicbelow.

Themostradicaland,tomymind,devastatingcriticismthatcanbeleveledagainsttheselectionisttheoryisthatevenifwecould

formulatetherequireddistinction,undernoplausibleunderstandingofthedivisionbetweenpurposiveselectingandmerediscriminationcannaturalselectionbeplacedontheteleologicalsideofthefence.Andifnaturalselectionisnotselectionatallinanyremotelyteleologicalsenseoftheterm,thentheselectionisttheoryentirelyfailstoconnectfunctiontalkinhuman

affairswithfunctiontalkinbiology.Noextensionoftheconceptsfromtheirmentalisticparadigmispossible.Thecybernetictheorymayfailtograntafunctiontothereproductivesystem,butselectionismfailsmoregrandly,rejectingallnonconsciousteleology.

Todemonstratethejusticeofthischarge,letusconstructseveralexamplesofselectionprocessesthatincludesomeextraquality,somethingthatliftsthemabovetheclassofmeresortingoperations;andletusthencomparethesestandardsofpurposiveselectionwiththewaynaturalselectionworks.

Lookingfirsttothesourceofourteleologicalparadigms,humanpurposiveness,wecanfindacluetothedifferencebetweenselectingandmerediscriminatinginoneofWright'sexamplesparadoxically,inwhatisomittedfromit.Whenaconsciousdesignerhasproducedthemechanism,Wrightsays,thestatementthat"XwasdesignedtodoZsimplyentailsthatXistherebecauseitresultsinZ"(1973,p.165).ButonlyinspecialcaseswouldX'sactuallydoingZbeoneofthecausalantecedentsthathavebroughtXtoitspresentsituation.Theetiologicalstorymayormaynotincludethatperformance,butitmustincludethedesigner'sexpectationsthatXwilldoZ.Wemaytakethatexplanationforgrantedifweassume,asWrightseemstodo(p.164),thatthedesigner'sexpectationsareinfallible,buteventhenwecannotleaveitoutoftheetiologicalpicture(Woodfield1976).X'sdoingZinthepastmayhavecontributedcausallytothedesigner'sexpectation,andsotohischoiceaswell,butnotnecessarily;theexpectationmayhavebeenbasedontheoreticalcalculationsinstead.Whatmattersistheexpectation,notanyactualinstancesofX'shavingdoneZ.Incontrast,ifthedesignerselectedthepartforinclusioninthedesignwithoutanyexpectationsofitsperformance,theselectionwouldbesimplywhimsical,merediscriminationwithoutapurpose.Itwouldbeliketherunningwaterthatsortsthegrainsofsandandothermaterialinthebedsofstreamsaccordingtotheirsizeanddensity.Sodoesthe

swirlingwaterinaprospector'span;butthediscriminationthattakesplaceinthepanispurposivebecauseitisbuiltintothecausalinteractionsofahighlycomplexselector,apersonwithadispositiontoemploythenuggetsinthepursuitofhighlivinginDodgeCity.TheconjectureIdrawfromtheseexamplesisthis:

Purposiveselectiondiffersfrommeresortinginthattheselectingagentormechanismhassomeinternalorientationtowardtheselectedobject'sperformanceinthefuture.

Canthisconjecture,thatanorientationtowardthefutureistheadditionalingredientthatconvertsmerediscriminationintopurposiveselection,beextendedtononconsciousselectors?Thefollowingexampleshowsthatitcan.Thesensorinaheat-seekingmissileisadevicethatrespondsinoneway(anoutputsignal)tosourcesofinfraredradiationandinanother(nooutput)toallotherthings.Thesensordiscriminates,therefore,betweenthesetwoclassesofobjects.Letusplacethesensorinitspositioninthefeedbackmechanismthatguidesthemissiletowarditstargetsbutdisrupttheloopatthecausalrelation,F,theeffectorconnection.Ofthisdefectivemechanismthemostwecansayisthatitdiscriminates.Nowletusrestoretheintegrityofthefeedbackloop.Equippedwithaninternalstatethatdisposesittopursuetheobjectsithasidentified,themissilenowmaybesaidtoselectthemintheteleologicalsenseoftheterm.Generalizingthemoralwehavedrawnfromtheparadigm,letusstipulatethatanecessaryconditionofpurposiveselectionisthattheselectorperformitssortingwithanorientationtowardsomeendorgoal.Idonotsuggestthatthecombinationofdiscriminationwithfuture-orientationamountstoasufficientcondition,butitisnecessary.ThedistinctionWrightdrawsbetweenpurposiveandnonpurposiveselectioniscrucialtotheselectionistanalysisofteleologyinnaturalobjects;hence,thisnecessaryconditionmustbesatisfiedsomehowbytheevolutionaryprocessiftheselectionisttheoryistofulfillitspromise.

Butnaturalselectionisnotorientedtowardthefuture.Wehavelearnedthatmuchbywatchingneo-DarwinismwinoutoverLamarckianideas.Anorganism'sneedforamutationdoesnotguaranteethatitwillhappen;eventhoseneededchangesthatsavea

speciesfromextinctionaresimplyluckyaccidents.Noanticipationofanysortinfluencesthecharacterofamutation.Norneedpresentorfutureplayanypartindeterminingtherateofmutation.Anindividualorganism,facedwithdangerofanunusualsort,willacceleratetherateatwhichittriesanddiscardspossiblesolutions;butaspeciesinanalogouscircumstancespossessesnomechanismforsteppingupitsgeneticexperimentation.Onthisaccountnaturalselectiondoesnotsupportfunctiontalk.

Thesamenegativejudgmentwithregardtotheallegedteleologicalcharacteroftheevolutionaryprocesscanbereachedbyaparallelandsimplerroute.Considerthefollowingweakerandevenmoreobviouscondition.Aselectionprocessisteleological,notmeresorting,onlyifitinvolvesatleasttwodistinctthings,aselectorandaselectee.Thisconditionmayseemsoself-evidentasnottoneedexplicitmention:Howcouldaprocessbecalledselectionifthereisnotaselectorselectingsomething?ButWrightdiscountsthispossibleobjection.Naturalselection,headmits,"isreallyself-selection,nothingisdoingtheselecting;giventhenatureofX,Z,andtheenvironment,Xwillautomaticallybeselected"(1973,p.164).Wrightseemstoclaimthatnaturalselection'sonlypeculiarityisitsoccurringautomatically,butthatselectingdoeshappen,nevertheless.Buthowcouldtherebeadoingthatnothingdoes?

Sortingcanbereflexive,ofcourse;agroupofantelopefleeingfromalionsortthemselvesintofront,middle,andrearranksbytheirownactions.Andperhapsinspecialcircumstancesaselectorandthethingselectedcanbebutonething:Theselectormustbecapableofbeingboththesubjectandtheobjectofitsownpurposiveactivity.Forexample,thepresidentofafacultysenatemayselecthimselfforappointmenttoanadhoccommittee.Idonotknowwhatwouldbethesmallestnumberofsimplercyberneticalcircuitsrequiredtobuildanautomatonthatcouldselectitself.Itwould,Isurmise,havetobeagoal-seekingmachinewhich,liketheheat-seekingmissile,isabletoestablishcausalconnectionswithexternalobjects,socompletinganoverallfeedbackloop.Itwouldbeable,second,todiscriminatebetweentheseobjectsandothersbymeansofsomedetectedproperty.Third,theautomatonwouldbeabletodetectthatsamepropertyinitselfandrespondinthesamewayasitnormallydoestoexternalthings.Isuspect,lastly,thatthecapabilityforthisdoubleparticipationinapurposiveactivitywouldberootedinahighdegreeof

organizationalcomplexitythat,forexample,anyorganismthatcouldselectitselfcouldalsolaughatitself.Couldanyorganismlesscomplicatedthanahumanbeingattainthisrank?Itseemsdoubtful;yettheselectionisttheory,accordingtoWright,musthaveself-selectionatalllevelsoftheevolutionaryprocess.Butcertainlyanamoebafallsfarshortoftheabilitytostandinforexternalthingsastheobjectofitsownpur-

posiveactivity.Certainly,too,themolecularreplicatingmechanismsthattriumphedovertheircompetitorsintheprimevalsoupweretoosimpletobecalledself-selectors.Appliedtothetypicalevolutionaryetiology,self-selectionisjustamisnomer.Volunteersdonotselectthemselves;theyputthemselvesforwardtobeselectedbythecommandingofficer.Theteamsthatparticipateintheworldserieshavenotselectedthemselves;theyhaveclimbedtothetopoftheirrespectiveheapsduringtheregularseason,fromwhichpinnaclesthecommissionersofbaseball,followingtherulesoftheleagues,selectthemfortheseries.Norhavethemanyextantorganismsthatadornourplanetselectedthemselves;rather,theancestorsofcontemporarylivingthingshavedonebetterthantheircompetitorsatgeneratingcopiesoftheirgenes.Darwin'sromanticmetaphorofselectionbyNatureismuchlessfaithfultohisfactsthanAlfredRussellWallace'sunsentimental"struggleforexistence."

Theselectionisttheoryerrsbyfocusingonthewrongcomparison.Paradigmsfromhumangoalseekingcanbeconnectedtohomeostasisbyanaturalextensionoftheconceptsofgoal,adaptation,andsurvival.Paradigmsfromconsciouschoosing,however,canbecarriedovertonaturalselectiononlybystretchingtheconceptofselectiontothesnappingpoint.Whatisleftinourhandsisalifelessmetaphor.

Theconceptualkeytounderstandingtheteleologyinherentinlivingthingsandtheirevolutionisnotselectionbutsurvival.Togetourthinkingstraightweneedtolookintherightplaceforthesourceofmeans-endrelations.Selectionismpointstotheenvironmentalcontextoftheorganism'sevolution.ButnatureisinnowaylikeakindlybutnonpersonalLutherBurbank.Consideraswimmingcoachwhoselectsherteambythrowingtheentirefreshmanclassintothepoolandsigningupthosewhofloat.Thecoachselects,becausesheexpectsherchargestowinafewswimmingcontests,butthepoolonlysorts.Naturedoesnotselecteither;itdoesnotlookbeyondthepresent

sceneofcarnageandstarvation(see,e.g.,Williams'seloquentparagraphonthistheme,1966,p.255).Ifwewouldfindteleologyinthatscenewemustlookwherethecybernetictheorypoints:notatthegrandschemeofthingsbutattheindividualstrugglers.Therewefindgoalseekingwithanobviouskinshiptoourown,survivalactivelysought,andadaptationobviouslydirectedatends.

AsJohnDeweysawclearlyenough,

Interestshiftsfromthewholesaleessencebackofspecialchangestothequestionofhowspecialchangesserveanddefeatconcretepurposes;shiftsfromanintelligencethatshapedthingsonceforalltotheparticularintelligencewhichthingsareevennowshaping.[1910,p.15]

WhatDeweyseemsnottohavenoticed,however,althoughitwasobviousalreadytoWilliamJames,istheradicallymechanisticflavorofDarwin'swork.Theconcreteandindividualpurposestowhichpost-Darwinianbiologydirectsourattentionaresimplyspecialmodesofinteractionamongmaterialparticles.

Adaptationand"Adaptation"

Whatdoesthecollapseoftheselectionistapproachsignifyforoureffortstounderstandteleologyintherestofnatureandinhumanaffairs?Inparticular,whatsensecanwemakeofselectionism'sveryownparadigms,learningbytrialanderrorandconscious,deliberativechoosing?Withonepossiblyimportantexception,theindicationsarethatwecandoverywellwithanunalloyedcyberneticism.Ihavediscussedonefavorableomen,namely,theheat-seekingmissilethatcanbesaidtoselecttargetspurposively,becauseitisorganizedasagoal-seekingmechanism.Indeed,farfrombeinguselessfortheanalysisofselectionmechanisms,thecyberneticalapproachprovidestheonlymeanswehavefoundfordistinguishingsortingprocessesthatserveanendfrommerenonpurposivediscriminating.ManyotherexamplescanbefoundinPowers'scyberneticanalysis(1973;1978)ofhumanbehaviorofallsorts.Butdifficultiesmayarisewithregardtoconsciouschoosing,thehighest,mostessentiallyteleologicalofourparadigmsofselection.Itwillproverefractorytoacyberneticanalysisifweinsistthattheactofchoosingmustintroduceobjectivenoveltyintothecourseofevents.Ifrealchoicesareundeterminedbytheeventsthatprecedethem,ifradicalfreedomispartoftheessence

ofdeliberativechoosing,thencyberneticismfailstomakesenseofit,forthecyberneticalanalysisstandsfirmlyonamechanistic-deterministicviewoftheworld.Wehaveconstructedthecyberneticalexplicationoforientationtowardgoalsintermsofrigidcausalmechanisms.Ofcourse,noteveryonewouldconsideritsmarriagetodeterminismtobeaseriousfaultofthecyberneticalanalysis.Isimplynotethefacthereand

setasidethegeneralquestionofnoveltyuntilIreturntoitfromadifferentdirectioninchapter11.

Wheredoesselectionism'sfailureleavetheallegedfunctionalityofthereproductivesystem?Withnocredentialswhatever.Thatmayseemlikeanunsatisfactorywaytotreatgeneticsurvival,aroundwhichtheevolutionaryprocessisorganizedasifitwereagoal.Wemustfindawaytograntafunctionofsomesorttothemechanismsthatcopygenes,ifonlybecauseinsomerespectstheyholdtheupperhand,rulingthekingdomoflifeoftenfrombehindthethronebutsometimesinthePacificsalmon,forinstancewithruthlesspower.IrecommendthelastofthethreeoptionsIlistedabove;letusdividetheusesofteleologicalconceptsinbiologyintotwodistinctgroups.Ontheonehandweplaceusesthatarejustifiedbytheconceptofgoalorientationextendedfromhumanpurposing,andontheotherwesettheunabashedanthropomorphismsthatwegeneratebytreatingnaturalselectionmetaphorically,asifitweremorethanmeresorting.Inonecolumngothecyberneticalconceptsofgoal,goal-directedness,individualsurvival,adaptationinthefacultativesense,andfunction,allunderstoodaccordingtothecyberneticalmodels.Thesearethetrulyteleologicalconcepts.Intheothercolumnwecollecttheconceptsofnaturalselection,criterionofselection,geneticsurvival,adaptationintheevolutionarysense,and(again)function,explicatedintheneo-Darwiniansense.Becausenaturalselectiondoesnotqualifyasteleologicalsorting,thecoatofarmsofthesecondfamilyofconceptsdisplaysthebendsinister.Thesearethemerelymetaphoricalusesofteleologicalterms.Arobinselectsabitofstringforanest;Naturehas''selected"theshapeoftherobin'sbeak.Acat'sirisesadapttovaryinglevelsofillumination;thefrontalorientationofitseyesis"adapted"toitspredatorylifestyle.Anoaksurvivesforahundredyears;thepatternofitsgenes"survives"formillions.

Disdainfullynow,wesquintthroughinvertedcommasatsomeof

modernbiologists'favoritelocutions.What,ifanything,canbesaidintheirfavor?Wecanpointoutthis:Thesenseof"function"thatweapply,forexample,tothetailofthepeacockortotheatrophyingofthePacificsalmon'sdigestivetract,thoughweak,isjustifiedsubjectively,becauseofalegitimateinterestwetakeinthosemechanismsandprocesses.Wehavegoodreasontopaymoreattentiontothefactthatthepeacock'sdisplayoften

leadstotheproductionofpeachicksthanwedotothefactthatitalsotendstodistributebitsofbrightcoloraboutthelawn.Wementiontheconnectionwiththenextgenerationwhenweexplainhowapproximatecopiesoftheseintricateanddecorativemechanismsgetconstructedyearafteryear.Theetiologyisnotpurposive,aswehaveseen,buttheoutcomeoftheprocessandthemechanismsbywhichitoccursarealwayswonderfulandsometimesbizarre.Ifweusethehonorificterm"function"todistinguishthecausalconnectionsthatliewithinsuchasequence,whocanblameus?

ThisclassificationofthemachineryofreproductionresemblesthewayonewouldstudytheinventionsofthecartoonistRubeGoldberg.Inatypicalcartoonmuchactivitygoeson:Aballrollsdownaplankintoabucketbalancedonaseesaw,themotionoftheseesawignitesamatchthatburnsthroughastringthathasbeensupporting...,andsoon.Buttherollingballgeneratessoundwavesasitmoves,itbouncesoutofthebucketandcontinuestorollalongthefloor,andsoon.Whydoweloseinterestintheballafterithascausedtheseesawtomovewhydowewanttocallitsactionupontheseesawitsfunction?Thereisatwofoldreason,neitherpartofwhichalonewouldjustifytheterm.First,thelineofcauseandeffectthatpassesthroughtheballtotheseesaw,thematch,andbeyondleadstoaspectacularorentertainingresult,whereasthelatercareeroftheballaffordsonlyscantamusement.Second,wepresumethatanythingsoelaboratemusthavebeeninventedbyanagentwithapurposeandacapacityforamusementlikeourown.Themachineoriginatedinapurposivecontext;itsinventormusthaveputtheballinthemachineinordertomovetheseesaw.

Mitosisisanevenmorecomplexchainofcauseandeffect,andonethatbranchesoutatmanypointsaswell.Everybranchbutonefailstogripourattention,andthatoneseemsalmostmiraculous.SothefirstreasonforascribingfunctionstothepartsofaGoldbergianmachine

appliesevenmorestronglytoreproduction.Butdoesthesecond?Doescellularreplicationservesomelarger,objectivelyidentifiablepurpose?Ifsomeoneorsomethinghadputthismachinerytogetherforapurpose,replicationitcertainlywouldhavebeen.Butatthispointourintellectlosesitsgriponourinstincts.IntellectfollowsDarwin,whohasshownushowthismachinerycouldhavebeenassembledpurelybythe

operationofblind,undirectedprocesses.Consequently,thepurposivebackgroundismissing,andteleologicaltermsarenotappropriate.ButinstinctsideswithWilliamPaley.Wecanscarcelyfindwordstodistinguishtheinterestingsequenceofeventswithoutusinglanguagethatsuggestsachoreographerdirectingthequadrilleofthechromosomes;wefallintoteleologicallanguage.Darwindid,too,thoughhedisavowedanyseriousintentbehindhisuseofsuchmetaphors.Sodomodernbiologists.ButletusbeclearaboutwhattheymeanwhentheycallthereplicationofDNA"survival"andthegenerationofprogenyan"ultimategoal."Theyknowbetter.Thesetermsaremerelyconvenientandcolorfulwaysofdistinguishingfromallotherswhatweconsidertobetheinterestingthreadinthecausaltangle,theonethatleadstoanastoundingresult.Unliketheapplicationoftheterms"function"and''goal''inhomeostasis,theapplicationhereispurely,infactemptily,metaphorical.

Cyberneticismdistinguishesjustwhereaclarifyinglineshouldbedrawn.Univocalselectionismdoesnot.Weneedtheline,forwespeaktooreadilyofevolutioninteleologicalterms.Becausecarefulmanagementofstudfarms,themostassiduousselecting,andinfinitepatiencewouldberequiredofgenerationsofanimalbreedersinordertoconvertEohippusaccordingtoprescriptionintothemodernzebra,weeasilyforgetthatNaturedidthejobwithitseyesclosed.Individualcats,cockroaches,orearthwormsareindubitablygoal-seeking,end-directedsystems;mustnot,therefore,thesystemthatproducedthembeatleastasteleologicalasthey?Howcouldpurposegrowoutofunpurpose?Inthosequestionslietheseedsoftheargumentfromdesignandtheromanticviewofnature.ButthecentralachievementofDarwinismistoshowhowjustsuchathingcanhappenmechanically.Individualswiththeireyesonthefuturecanbeconstructedbyaprocessutterlyblind.

Theselectionistconjecturefailstodojusticetoteleologyateitherend

ofthescale.Humanselectingispurposiveonlywhenincorporatedintoanefforttoachieveagoal,andthe"selection"donebynatureonevolvingspeciesisnotteleologicalatall.Butwithcyberneticalconceptswehaveconstructedathoroughlymechanistic,hencereductive,explicationthataccommodatesallteleology,fromhumanpurposestomeans-endrelationsinthesimplestlivingthings.Tobesure,theargumentsIhavepresented

donomorethanestablishtheplausibilityofthisclaim.Thepromiseofthecyberneticalprogramcanbefulfilledonlybyscientistsworkingatalllevelsinthehierarchyofteleologicalsystems.Butargumentsforplausibilitywillcarryusalongwayaswetrytoevaluatetheworldviewofatomisticreductionism.

Isitreasonabletobelievethatahumanbeingisnothingmorethananespeciallycomplicatedexampleofwhatcells(orgenes,oratoms)candowhentheyfalltogetherinacertainway?Thefactthathumansentertainpurposes,makedeliberatechoices,andpursuegoalsgivesusinitselfnogroundsforrejectingtheproposal.

SevenNonreductivePhysicalismThestandardreductionistpositionclaimsthattheoriesthattreatcompositethingsastheactorsinthecosmicdramacanbejustifiedonlybytheirrelativemanageability,notbytheirfidelitytofacts.Butifsuchtheoriescouldbejustifiedongroundsmoresolidthanthatofmereconvenience,theentitiestheypickoutmightberescuedfromobsolescence.ThemodificationsintroducedbyJerryFodor(1975)toourunderstandingofreductionismandtherelatedsuggestionsofKarlR.Popper(1972),ofMichaelPolanyi(1968),andofDonaldT.Campbell(1974b)areinterestingintheirownright,becausetheyrevealcomplexitiesintheprogramoftheoryreduction.However,Iintendtoexaminethemstrictlyinordertoseewhethertheycanhelpusrestoreameasureofontologicalrespectabilitytotheobjectsofcommonsense,organismsespecially.

Theirstrategycommandsourattentionbecauseofitsaudacity:Theyconcedetotheatomistprogrammorethanseemspossiblewithoutalsosurrenderingunconditionally;yettheyclaimtoestablishanautonomyfortheupper-levelsciencesand

theirdesignatedcausalagents.Takingastanddeepinterritoryusuallythoughttobeheldbyreductionism,thesetheoriesmaintainthatcertainmechanisms,thoughcomposedofnothingbutmaterialparts,neverthelessrefusetobereducedtotheirlevel.

AsamatterofstrategyIdeferconsiderationofmoreradicalproposals,scrutinizingfirstthoselinesofdefensethatleavethegeneralprogramofscientificmaterialismuntouched.ThetheoriesIwishtoexamineheredeserveattentionbecausetheydonotchallengethematerialistprogram,yettheyholdoutthepromiseofmitigatingconsiderations.LetusturnfirsttoFodor'sanalysisoftherelationsbetweenthespecialsciencesandphysics.

TokenPhysicalism

Scientificlawsandtheoriesmakegeneralizationsaboutkindsortypesofentity.Anaturalkind,accordingtoFodor,isasetofobjectswhichare"tokens"(individualexamples)ofatypethatfiguresinascientifictheory.Thetheoriesgeneralizebygroupingtogetherthings,events,orprocessesthatsharesomecharacteristicproperty.Eachscience,totheextentthatitproduceslawlikegeneralizationsandnotmerecatalogsoffacts,recognizesandnamesitsownnaturalkinds.Fodorarguesthatthenaturalkindsofpsychologycannotbeexplicatedintermsevenofthenaturalkindsthatbelongtoneurophysiology;hence,afortiori,psychologicalkindsareirreducibletothoseofphysics.

Fodorbuildshisargumentontheobservationthatthethings,situations,orprocessesgroupedtogetherastokensofasingletypebyanupper-levelorspecialscienceareoftenradicallydisparatewithrespecttothetypesthatfigureinlower-leveltheories,includingthetheoriesofphysics.Thispositionisjustlycalledphysicalism,fortworeasons.First,Fodorstipulatesthateverytokenofanupper-leveltypeexemplifiessomephysicaltypeorother;yetheclaimsthatinmany

interestingcasesthetypesmentionedinupper-leveltheories"cross-classify"typesoflower-levelthings(1975,p.26).Thetokensofanupper-leveltypecannotbecharacterizedbyasinglelower-levelpredicate;someoftheinstancesofasingleupper-leveltypebelongtooneatthelower-level,sometoanother,sothattheysharenocharacterizinglower-levelproperty.Second,Fodorstipulatesthatthelower-leveltheorymayexplainwhyeachtokenofalower-leveltypeisalsoa

tokenoftheupper-levelone,butitdoesnotexplaintheupper-levelgeneralizationasawhole.

Itsproponentsseethisanalysisnotjustasaninterestingobservationaboutthevarietyandcomplexityofthereductionistprogrambutalsoasaninvestmentthatofferstopayontologicaldividends.Fodorintendstojustifythespecialsciencesbyshowingthemtobenecessary,forreasonsthatgobeyondthemerelyepistemological.Unlikehisown,theusualreductionisticjustificationofthespecialsciences,hesays,is

entirelyepistemological.Ifonlyphysicalparticlesweren'tsosmall(ifonlybrainswereontheoutside,whereonecangetalookatthem),thenwewoulddophysicsinsteadofpaleontology(neurologyinsteadofpsychology,psychologyinsteadofeconomics,andsoondown).[1975,p.24]

Fodoroffersajustificationthatgoesbeyondconsiderationsofutilityandbrevity:"Therearespecialsciencesnotbecauseofthenatureofourepistemicrelationtotheworld,butbecauseofthewaytheworldisputtogether"(p.24).Itisclear,too,thatFodoroffershistheorypartlyasananswertothereductionistattackonupper-levelentities;thatis,asareplytophilosopherswhoconsiderpsychologicaltheoriesas"aptfordehypostatization"(p.26).DavidHull(1974)findsasimilardisparitybetweenthetype-termsofMendeliangeneticsandtheirlower-levelcounterpartsinmoleculargenetics.AndWilliamWimsatt(1976),whousesHull'sanalysistosupporthisowntreatmentoftheoryreduction,alsowieldsinterleveltypedisparityindefenseofupper-levelentities.Giventhisricherunderstandingofreduction,hesays,''upper-levelphenomenaareseenneithertobeeliminatednortobe'analyzedaway'''(p.13).

Fodor's"tokenphysicalism"maybesummarizedinthefollowingfivetheses:

1.Everyspecificinstanceofarealthingorprocessisthoroughlyphysical;thatis,nothinghappensinanyprocessthatisnotcompatiblewithbasicphysicallawornotinprinciplepredictablebymeansoftheselawsfromantecedentphysicalconditions.

2.Nevertheless,thereexistupper-levellaws,suchasthegeneralizationsofbiology,psychology,andeconomics.Theselawsrefertotypesofentityandprocessthat"cross-classify"physicaltypes.That

is,someupper-levellawspickoutandgrouptogetherintotypescertainsetsofthoroughlyphysicalthingsthatsharenocharacterizingphysicalproperty.Thesesetsconstitutebiologicalorpsychologicaloreconomictypesbutnotphysicaltypes.

3.Theupper-levellawsandgeneralizationsarenotspecialcasesoflower-levellawsorapproximationstothem.Thus,theupper-levellawscannotbetranslatedintostatementsandgeneralizationscastinlower-levellanguage.Tobesure,eachspecificoccurrencecoveredbytheupper-levellawisalsoexplainedbysomelower-levellaworother.Butthemanyinstancesofthesingleupper-levellawarecoveredbymanydifferentlower-levellaws.

4.Yettheregularitiesexpressedbytheupper-levellawsarethereinthephenomena.Nottonoticethemistomisssomethingobjectivelytrueabouttheworld.Acompletedescriptionwill,therefore,includethesegeneralizationsandthuswillrefertoupper-leveltypesofentity.

5.Becausethetermforanupper-levelkindcannotbetranslatedintoanyfinitesetoftermsforlower-levelkinds,wemustadmitthattheexemplarsoftheupper-levelkindscontributetocausalactivitywithjustasmuchontologicalrespectabilityasdothetokensofthelowerlevel.Forexample,wemustsaythatcondominantgenepairs,statesofcognition,andmonetarysystemsarejustasirreduciblyrealaselectrons,protons,andneutrons.Inshort,ourtalkabouthumanbeingsandothercommonsenseobjectscannotbe"dehypostatized."

Whatqualifiesasalower-levelkind?Onthispoint,Fodormakesanimpossibledemandonthelower-levelaccountbyspecifyingthatthelower-levelkindmustbeanaturalkindatthatlevel;thatis,itmustfigureinaproperlawatthelowerlevel(1975,p.16,25).Thisrequirementisunreasonablebecausewedistinguishlevelsaccordingtothepart-wholerelation;lower-levellawsqualifyassuchbecausetheyrefertothepartsofupper-levelthings.Therefore,anaturalkindatthelowerlevelmustnecessarilybeonlyapartofanupper-levelthing.Accordingtothisrequirement,nolower-levelkindcouldpossiblybecoextensivewithanupper-levelkind,andFodor'sthesis

wouldbetriviallytrue.Amorereasonablecriterionofwhatcountsasalower-levelkindisthis:Itmustbecharacterizableinthelanguageofthelowerlevel,thatis,intermsoflower-levelthings,theirarrangementsandcausalinteractions.

Canthetheoriesofaspecialscience,appliedtophysical

things,classifythemintononphysicalcategories?Onthefaceofitthisquestionseemstodemandanegativeanswer,forifkindsarepickedoutbytheircharacteristicproperties,thequestionwouldbeequivalenttoaskingwhethermerelyphysicalthingscanhavenonphysicalproperties.Andifsomethinghasnonphysicalproperties,howcanitbesaidtobeamerelyphysicalthing?ButFodor'sargumentcannotberefutedsoglibly,asafewsimpleexampleswillshow.

Theupper-levelterm"meteorite"classifiesrocksaccordingtoasharedtypeoforigin,acommonhistoricalsetting.Theterm"impurityatom"(asinasemiconductor)collectsitsobjectsbyvirtueoftheirbeingsurroundedbyatomsofadifferentchemicalkind.Istheresomephysical,chemical,orstructuralpropertypossessedbyallmeteoritesandonlythem?Possiblynot.Theremayberockslyingaboutthatareinfactmeteoritesbutarenotrecognizableassuchbecausetheyshownotraceoftheirhistory.Andthereisnothingaboutanantimonyatominitselfthatqualifiesitasanimpurityatom.FollowingFodor,wecansaythatthekind''impurityatom"coverssomebutnotallantimonyatomsandsomebutnotallarsenicatoms;and"meteorite"cross-classifiesseveralphysical-chemicalkindsofrock.

Fodordiscussestwoscientificallyimportantwaysinwhichanupper-leveltypecancross-classifytypesofalowerlevel.First,hesuggeststhatthetokensofagivenpsychologicalorbiologicaltypemayshareacommonbehavioralconsequenceormakethesamefunctionalcontributiontotheorganism.Whatturnsbimetallicstripsandtubesfilledwithmercuryintotemperaturesensorsisthemanneroftheirincorporationinlargersystems.Second,followingHilaryPutnam,Fodorsuggests(1975,pp.18ff.)thatanentiresystemmaybecharacterizedasatokenofapsychologicaltypebyanabstractfeatureofthewayitisconnectedtogether,bywhatIshallcall,borrowingandstretchingatermfromelectricalengineering,itswiringdiagram.

Computingmachinesandnervoussystemsmayembodythesamewiringdiagramyetbebuiltofquitediversematerials,rangingfromgearsandleverstosemiconductingchipstolivingcells.Therefore,themembersofahomogeneousorganizationalorstructuraltypemaybeheterogeneousastotheirdescriptionintermsofhardware.

Ishallconsiderthesetwosuggestionsseparately,askingabouteachwhethertheindicatedmismatchbetweenthetypesbelong-

ingtoupperandlowerlevelsprovidesabasisfortheautonomyoftheupper-leveltheoryandafirmontologicalfootingforthethingsthetheorynames.Cantokenphysicalismrescuetheobjectsofcommonsenseexperience?

Myanswerwillarriveintwostages.First,Ishallarguethatthegeneralizationswemakeaboutobjectscharacterizedbyrelationalproperties,includingtheabilitiestogeneratebehavioralconsequencesandtoperformfunctions,areimplicitinthegeneralizationswemakeaboutthestructuralpropertiesofthesystemsinwhichthoseobjectsplaytheirparts.Ifthatisso,thenthesecondofFodor'scategoriesofupper-levelentityswallowsupthefirst.Next,Ishallaskwhethertheatomistreductionprogramcancopewithgeneralizationsaboutsystemscharacterizedbytheirwiringdiagrams.Fodorisnotaloneinsuggestingthatatomismmustfailinthisrespect;hisargumentresonateswithsomespeculationsofPopper,Polanyi,andCampbell.Ishallargue,inreplytoallofthesespeculations,thatgeneralizationsofthissortareimplicitinlower-leveldescriptionsinapeculiar,thoughthoroughlyreductionistic,way.Consequently,althoughwemayindeedencounterdisparitiesbetweentypesresidingondifferentlevels,thedisparitydoesnotjustifyenrollingtheentitiesnamedbyupper-leveltheoriesalongsidetheatomsonourrosteroftheworld'splayers.

CausalConsequences

LetusexaminefirstasimpleexamplethatFodordoesnotdiscuss.Catalystsandenzymesfithiscategoryofentitiesthatcontributetotheinternaleconomyofanorganizedsystem.Takethetypeofsubstancethatcancatalyzetheoxidationofhydrogen.Quitelikelyitisimpossibletospecifyaclassofchemicaltypes,suchasketonesorLewisbases,sothatalloftheseandonlythesesubstancesareabletocatalyzethereaction.

Theupperlevelappropriatetothisexamplereferstochemicalsubstanceslikeoxygenandwaterasthecausalagents.Thelower-leveltheory,quantumchemistry,appliesthelawsofquantummechanicstoarrangementsofelectronsandatomicnuclei.Inareductionisticreconstructionoftheworldfrombasicphysicaltheory,substanceswouldbeidentifiedascatalystsbyapplyingquantummechanicslaboriouslytothetheoreticalmodelofa

mixtureofoxygen,hydrogen,andtheprospectivecatalystandfindingoutfromthetheorywhetherthecandidatesubstancewouldcatalyzethereaction.Atthedescriptivelevelofquantumchemistry,theworldconsistsofatomicnucleiandelectronsinshiftingarrangements,andalltheworld'sprocessesareseenasactionsperformedbytheseagents.Thepredicate"catalystoftheoxidationofhydrogen"doesnotplayaroleinquantum-chemicalexplanations,simplybecausequantumchemistryisconcernedwithindividualcatalysts(andnoncatalysts),notwiththeclassofcatalystsasawhole.

Yetthepredicateiscertainlydiscoverableinthequantum-chemicaltreatment.Someonewhoseentirestoreofinformationabouttheworld'saffairswasconveyedinthelanguageofquantumchemistrywouldbeabletoformgeneralizationsaboutthecatalystsofthisreactionaswellassomeonewhoseknowledgewaslimitedtosuchthingsasflasksandreagents.Thequantum-chemicalpictureoftheworldcansubstitutefortheworlditselfasinductivesupportforupper-levelgeneralizations.Wehave,therefore,noreasontothinkthatthelower-leveltheoryleavesoutfactsthatareexpressibleonlyinupper-levellanguage.Besides,onlyquantumchemistry,whichtreatselectronsandnucleiasthecausalagents,canexplainthecatalyzingaction;hence,quantumchemistryliesclosertothetruthaboutthisportionoftheworldthandoesanyupper-leveltheorythattreatschemicalcompoundsascausalagentsandleavestheirinteractionsunexplained.

CatalysishasalltheinterestingfeaturesofFodor'sanalysisoftheoryreduction.Thereappearstobeacompletemismatchbetweentheupper-leveltype,thecatalystsofthereaction,andthevariouscategoriesofchemicalspecies.TheexamplealsoillustratesFodor'sobservationthatthelower-leveltheoryexplainsineachspecificinstancewhyachemicalsubstanceisorisnotacatalystofthereaction.Yetthelower-leveltheoryunquestionablyapproachesmore

nearlytothetruth.Catalysisisacounterexampletotheclaimthatthedisparitybetweentypesatupperandlowerlevelsprotectstheupperlevelfromreductiontothelower.

PropertiesofGenes

Arrangementsofnucleiandelectronsthatcancatalyzeagivenreactionarecharacterizedbytheirpotentialconsequences,by

whatmightensueiftheywereincorporatedintoagivencontext.Incontrast,theMendelianpredicatesHull(1974)discussesarecontextualpredicatesthatrefertoactualconsequences.HullsuggeststhatnocorrespondencecanbeestablishedbetweencertainMendelianpredicatesandpredicatesforkindsofmolecularmechanismunlessonecorrelatestheMendelianterm"withtheentiremolecularmilieu"(p.42).Thisexpedientproducessuchafar-reachingreorganizationofMendelianconceptsthatwhatwasintendedtobereductionbecomesreplacement.Wimsatt(1976),however,insiststhatwehavehereafairlytypicalcaseofinterlevelreduction,anexampleinbiologyofTaylor'sandFodor'ssuggestionsthatupper-leveltypeshavenoneatcorrespondencewithlower-leveltypes,hencethatgeneralizationsemployingtheserecalcitrantpredicatescannotbereplacedbytranslatingthemintothelanguageofthelowerlevel.

Letustakeacloserlookatthisargument.Mendeliangenetics,becauseitdealswithmacroscopicphenomena,referstogenesashypotheticalbodiescharacterizedbytheireffectsinthephenotype.Butdefinitionsoftheform"xistheagentthatproduceseffectEinsystemS"arewildlyopen-ended.ThedefinitioncarriesnoguaranteethatxwilllieonthesamelevelofcomplexityasSorE,andthereislittlereasontoexpectthatthevariousagentsthatinfactproduceagivenkindofeffectwillhaveenoughstructuralsimilaritytobedistinguishedbyacommonintrinsiccharacter.Similareffectsdonotnecessarilyresultfromsimilarcauses.

Perhapstheearlygeneticistswhoworkedwiththeconceptofdominanceasarelationbetweengeneshoped,first,tocharacterizethosehypotheticalbodiesand,second,tofindthatdominancewasamatterofdirectcausalactionofgeneupongene.But,ifso,surpriseswereforthcominginbothendeavors.Thegeneturnedouttobemolecularinsize,breakingthroughtheneatseparationbetweenphenomenaatdifferentlevelsoforganization.Anddominanceproved

tobenotatallthedirectactionofonegeneuponanotherbuttheultimateoutcomeofanexceedinglycomplexmolecularprocess.OnemightoncehavesaidthatgeneAdominatedovergenea,butnowwesay,forexample,thatthephenotypiceffectsofaarenotnoticeableinthepresenceofthoseofA.Thestoryofgenetranscription,activation,andsuppressionislongandcomplicatedandmustbetoldatthemolecularlevel.

Thecontrastbetweenthermodynamicsasanupper-leveltheoryandMendeliangeneticsasaputativeupper-leveltheoryisinstructive.Inbothcasestheearlyworkersexpectedamicro-reductiontobepossible,butonlyinthermodynamicswasitpossibletorestrictthetheorytotheupperlevel,thatis,todevelopgeneralizationsthatquantifiedovermacroscopicbodiesonly.Temperaturewasdefinedbyits(potential)effects,withnoassuranceitwouldturnouttobeapropertyofwholebodies,thoughitdidturnouttobeso.Theriskwasgreateringeneticsbecausenotjustapropertybutacausalentity,thegene,wasdefinedintermsofitsmacroscopiceffects.Laterdevelopmentsshowedittobeamicroscopicentity.Thus,thehope(ifanyoneeverdidhope)thatMendeliangeneticsmightbeself-containedonthemacroscopiclevelcametonaught;becausethegeneisamolecularentity,anygenetictheorythatreferstogenesinevitablyresidesonthemolecularlevel.Infact,molecules,andsomethingliketheideaofmacromolecules,begantooccupythethinkingofevolutionistsataveryearlystage.HugoDeVries(1889;1910)speculatesthat

Thevisiblephenomenaofheredityare...theexpressionsofthecharactersofminutestinvisibleparticles....Thesepangens...[are]ofquiteanotherorderthanthechemicalmolecules...[yetare]composedofinnumerablesuchmolecules.[P.194]

AndDarwin(1890),onthenatureofhishypotheticalcarriersofinheritance,suggeststhat"probablymanymoleculesgototheformationofagemmule"(pp.37475).

ReplyingtotheantireductiveargumentsofHull(1974)andRuse(1973),WilliamK.Goosens(1978)arguespersuasivelythattheprogramofgeneticaltheoryallowedfromthebeginningthatthegenemighthaveachemicalstructuregovernedbythelawsofphysicalchemistry.Forthisreason,therelationbetweenmolecularand

Mendeliangeneticscannotbeviewedasinterlevelreduction.Goosenstermsthereduction"whole-partreduction"(p.91).Thermodynamicsappliesonlytomacroscopicbodies,andstatisticalmechanicsdealswiththeirmicroscopicparts;thus,statisticalmechanicsisappropriatelysituatedvis-à-visthermodynamicstobeitsreducingtheory.ButmolecularandMendeliangeneticsbothrecounttheactivitiesof(macro)molecules;

hence,theycannotstandintherelationoflower-andupper-leveltheories.MoleculargeneticsisnotamicroreducingtheoryforMendelian;itis,rather,thenaturaldevelopmentofMendeliangeneticsasitwastransformedfromatheorywithonefootunintentionallyateachleveltoonethatstandssquarelyonthelowerone.

LawlikeGeneralizations

Thescientificallysignificantupper-levelpredicatesarethosethatwecanemployinexpressinggeneraltheoriesandlaws.Letusconsiderthreesortsoflawlikestatements:generalizationsaboutobjectsdefinedbytheirspatialandcausalconnections,aboutpartsdefinedbytheirfunctionsinagoal-directedsystem,andaboutwholesystemscharacterizedbytheirwiringdiagrams.

SpatialandCausalContexts.

Thespatialsettingandcausalconnectionsofapartofalargersystemdonotdisappearfromthestoryaswedescendtolowerlevelsofdescription.Spatialrelationsremainwithoutchange,andcausalinteractionsthatmayappearmysteriousattheupperlevelbegintolosetheirmysteryasthelower-levelnarrativeintroducesthemicroscopicmechanismsthatestablishtheconnections.Therefore,reducingadescriptionofacontextuallydefinedindividualobjectpresentsnoproblemtotheatomistprogram.

Generalizationsaboutsuchobjects,however,requiresomeattention.Isubmitthatinterestingandprojectablegeneralizationsaboutthingsdesignatedbytheirspatial-causalsettingaregroundedonthelawlikecharacteroftheentiresetting.Letmesupportthisclaimbyadaptingastockexample.

Thegeneralization"Alltheobjectsnowresidinginmypocketare

madeofnickel"willnotsupportthecounterfactual"Ifxwereinmypocketnowitwouldbemadeofnickel."Yetthegeneralizations"Alltheobjectsnowresidinginmypocketaretravelingnorthat20km/h''and"Alltheobjectsnowresidinginmypockethavevolumeslessthan600cubiccentimeters"dosupportthecorrespondingcounterfactuals,simplybecausemypocket(alongwiththerestofmyperson)istravelingnorthatthatspeedandbecausemypockethasavolumelessthanthatamount.Counterfactualslikethesearesupported,ifatall,be-

causeofsomebackgroundfactsaboutthecontextandtheprinciplesthatgovernthem.

Ineachcasethereisareasonwhythegeneralizationholds.Itisacondensedversionofamorecompletestory,whichwhenfullytoldwillbefoundtorefertothewholecontextualsituation.Thegeneralization,therefore,appliestoaclassortypeofsystem,definedbyitspatternoforganization.Suchageneralizationwillbereducibleifthepatternis.

FunctionalContexts.

Next,considerentitiesdefinedbytheirfunctionalcontributiontoanorganism.Insofarasthecontributionisacausalconsequence,thiscategorymergeswiththeonejustconsidered.But,asIhavearguedinchapters5and6,ascriptionsoffunctionsimplythatthesystemcontainingthefunctioningpartisorganizedinagoal-directedway,eitherasasimplefeedbacksystemorasanestedhierarchyofthem.Compositesystemssuchasorganismsandautomatonsarecharacterizedbythepatternsinwhichtheyareorganized.Reducinglawlikegeneralizationsaboutfunctionalparts,then,requiresthereductionofdescriptionsthatcharacterizesystemsintermsoftheirorganizationalpatterns.Wehaveseenhowtodothatforthespecialcaseofgoal-directedmechanisms.Letuslookatthetaskmoregenerally.

OrganizationalPatterns.

Scientistsofallsorts,thoughinitiallyconcernedwithhowcertainobjectshappentobeputtogether,eventuallybroadentheirinvestigationtoincludeabstractpatternsofconnections.Theydosobecausemuchofthebehavioroftheobjectstheystudycanbeunderstoodbyreferencetotheirwiringdiagrams,withoutregardtotheparticularmaterialrealizationofthemthatinfactobtains.A

hydrodynamiciststudyingtheactionofwindonthesurfaceofwaterfindsthatthewavemotioncanbeexplainedbyreferencemerelytocertainabstractfeaturesofthecompositionandstructureofliquidwaterandthatthesefeatures,representedbyadifferentialequation,aresharedbyawidevarietyofothermedia.Wavemotioningeneralbecomesanattractivefieldofstudy.

Totheextentthatbiologistsandpsychologistsmerelycatalogthebehaviorofinsectsandpeople,ormerelydiscoverhowthesethingshappeninfacttobeputtogether,theirgeneralizations

aboutHymenopteraorHomosapiensarenotprojectabletolifeinotherregionsoftheuniverseandarenotmeanttobe(Smart1963).Iftheirscientificactivityislimitedtosuchcataloging,thereisnoquestionofreducingtheirlawstophysics,becausetheyproducenolaws.

Buttheydomore.Theirinterestinpatternsofconnectionsleadsthemtodistinguishkindsofsystemcharacterizedbytheirwiringdiagrams.Inthiswaybiologistsandpsychologistsmakegeneralizationsthatareprojectable,justasphysicistsdowhotheorizeaboutwavemotion.Ifapsychologicalstateinhumansischaracterizedbythewaythepartsoftheorganismareputtogether,withoutregardtotheinnerstructureofthoseparts,thenwhatwesayaboutsuchastatecanbeappliedtorobotswhosetransistorsandswitcheshavebeenwiredaccordingtothesamediagram.

Alawassociatingpropertiesorbehaviorswithawiringdiagramexplainsthemwithoutmentioningthedetailedconnectionsbywhichthediagramisrealized.Thiskindofexplanationfloatsfreelyabovetheleveloftheparts.How,then,canweobtainitfromadescriptionframedatthelowerlevel?Inchapter4wesawhowtosolvethisproblem.Thereweproducedaprescriptionfordiscerningthepresenceofthefeedbackpatterninalower-leveldescriptionofasystem.Isubmitthattheexplicationoffeedbackservesasamodelforthegeneraltaskofreducingpatternsofcausalconnections.

IhaveexaminedFodor'sanalysisfromanarrowperspective,concedingthatitpointsoutasignificantcomplexityintheprogramoftheoryreductionbutquestioningwhetheritmakesgooditsclaimtorescueorganismsandothermechanismsfromlosingtheirstandingascausalagentsbydefaulttotheirparts.Thelower-levelaccountexplainseachspecificinstanceofanupper-levellaw.Thisfact,concededbyFodortobeageneralfeatureoftokenphysicalism,

provesgenerallyfataltotheattempttomitigatereductionismbyshowingtheupperlevelofdescriptiontobeirreplaceable.Eachspecificinstanceisallowedtobenothingmorethananarrangementofparticles,andthecausalconnectionsineachinstanceareexplainedonlybyreferencetothem.Hence,theparticles,notthetokensoftheupper-leveltype,performthecausalactivity.InorderforFodor'stheorytoworkas

adefenseagainsttheatomistattackdescribedinchapter1,itwouldhavetoprovideareasonfortreatingindividualcompositethings,notmerelyclassesortypesofthem,ascausalagents.Butitfailsatthispoint,becauseitmustallowthelower-leveltheorytobenearerthetruthineveryindividualcase.

SimilarConjectures:Polanyi,Popper,andCampbell

Fodorisnotaloneinsuggestingthatreferencestowiringdiagramsinourupper-leveldescriptionsprotectthemfromattackbyreductionisticanalysis.MichaelPolanyi(1968)presentsanindependentargumentfortheirreducibilityofcompositesystemscharacterizedbytheirpatternsoforganization(inPolanyi'sterminology,theirboundaryconditionsor,simply,theirboundaries).Anywiringdiagramis''extraneoustotheprocessitdelimits."Ofmachineshesays,"Theirstructurecannotbedefinedintermsofthelawstheyharness"(p.1309).AndPolanyimakesthesameclaimaboutthestructuresoflivingorganisms.Nevertheless,heconcedes,thisobservationbyitselfdoesnotshowmachinesandorganismstobeirreducibletophysics.

Polanyidistinguishestwosortsofboundaryconditions.Thefirstistypifiedbytheshapeimpressedbyasaucepanonthesoupitcontainsandbythearrangementsofparticlesstudiedingeologyandastronomy.Thissort,heconcedes,canbereducedtophysics.Oftheothersort,suchasthepatternsofconnectionsinmachinesandinlivingorganisms,heclaimsirreducibility.

Doesthedistinctioncaptureanobjectivedifference?Polanyiseemstogivetwoanswerstothatquestion.Atonepointhesaysthatthenatureofourinterestinthesystemdetermineswhetherthepatternisofonesortortheother.Ifweareinterestedinthematerial,wehavethefirstsort;ifintheshapeorstructureimpresseduponthematerial,thesecond.Inthekitchenwecareaboutthesoup,notthesaucepan;butin

asculptor'sstudiointerestfocusesontheshape,notonthemarbleitself.Polanyiisquitedefiniteaboutit:"Byshiftingourattention,wemaysometimeschangeaboundaryfromonetypetoanother"(1968,p.1308).

RobertCausey(1969)hasturnedthisaccountofboundaryconditionsdecisivelyagainstPolanyi'smainargument.Ifthefirstkindofboundarycanbereduced,andifthesecondkindmaybe

madeoverintothefirstmerelybythinkingdifferentlyaboutit,Causeyargues,thenbothsortsarereducible.

However,Polanyi'ssecondwayofdistinguishingthetwosortsofboundaryescapesthiscriticism.Atanotherpointinhisessayhesaysthatorganismsandmachinesaresystems"underdualcontrol"(1968,p.1309)."CanthecontrolofmorphogenesisbyDNAbelikenedtothedesigningandshapingofamachinebyanengineer?"heasks,andanswersyes,becauseDNA"actsasablueprint."Sowhatdistinguishestheirreduciblesortofwiringdiagramisitshavingbeenimpressedonitsmaterialbysomeorganizingagent.Inmachinestheultimateactiveprincipleisthehumanmind:''Themindharnessesneurologicalmechanismsandisnotdeterminedbythem"(p.1312).Butinlivingorganismsthereisahierarchyofactiveprinciples,"eachlevelofwhichreliesforitsworkingsontheprinciplesofthelevelsbelowit,evenwhileititselfisirreducibletothoselowerprinciples"(p.1310).The''blueprint"actionofDNAisoneoftheseprinciples,butaboveitlies"asystemofcausesnotspecifiedintermsofphysicsandchemistry,suchcausesbeingadditionalbothtotheboundaryconditionsofDNAandtothemorphologicalstructurebroughtaboutbyDNA"(p.1310).Asanexampleofoneofthesehighercauses,Polanyicitesthe"integrativepower...whichguidesthegrowthofembryonicfragmentstoformthemorphologicalfeaturestowhichtheyembryologicallybelong"(p.1310).

Polanyi'ssuggestionthatprocessesatagivenlevelarecontrolledbyorganizingprinciplesathigherlevelsseemstoechoanideaexpressedearlierbyKarlR.PopperinhisComptonLectureof1965,publishedlaterinObjectiveKnowledge(1972).Popperisconcernednotdirectlywiththequestionofthereducibilityofnaturallawsbutwiththefreedomofhumanreasonandwill;yet,likePolanyi,hearguesthathigherprinciplescontrollower-levelprocesses.Popperseesinorganisms"ahierarchicalsystemofplasticcontrols"inwhichthe

lowerfunctions"areconstrainedandcontrolledbythehigherones"(p.245).

DonaldT.Campbell(1974b)advancesasimilarargumentinthecontextofthetheoryofnaturalselection.Campbellidentifieshimselfasareductionist;yethewarnsagainstasimplisticreductionism.Hearguesthatacompleteexplanationofbiologicalsystemscannotbeaccomplishedbyphysicsandchemistryalonebut

"willoftenrequirereferencetolawsatahigherleveloforganizationaswell."Campbelltermsthisactionofhigher-levelprinciplesupontheprocessesoflowerlevels"downwardcausation";bythishemeans"causationbyaselectiveprocesswhicheditstheproductsofdirectphysicalcausation''(p.180).

Theseexamplesofhumanactivityseemtodemonstratethepatterningofrawmaterialsbyapatternedcausalagent.Non-humanexamplesmayalsobefound:Thefeetofbirdsleavetheirimpressionsonthedampsandofabeach,andaseedcrystalcausesasaturatedsolutiontocopyitsorderedstructureintheprocessofcrystallization.SomethingliketheAristotelianideaofformalcauseseemstobeappropriatehere,asausefulandenlighteningsupplementtoouraccountofeventsintermsofefficientcauses.Butatissueistheadequacyinprincipleofanexplanatoryschemebasedsolelyonefficientcauses.

Thistalkofcontrolling,harnessing,andeditingderivesitsintuitiveappealfromapictureofengineersassemblingmaterialsaccordingtothepreexistingdesignofablueprint,ofsculptorsmakingtheirmaterialsconformtoanideapreviouslyconceivedintheimagination,andofpublishersapplyingliterarystandardstohaplessmanuscripts.Buttheanalogy,thoughattractive,issurelyfalse.

Systemscomposedofmanypartsnecessarilydisplaysomepatternorothereventhestarsaregroupedintriangles,Latincrosses,half-circles,andsoon.Butnowhereinnaturedowefindapatternthatarisesotherthanastheoutcomeoftheactionsoftheparticlescarryingontheirsmallaffairsaccordingtotheirindividualnatures.Evennegativefeedback,apatterncharacteristicofbothlivingsystemsandmachines,canbefoundinthelower-leveldescriptionofanorganismormachineanditscontext,asIhaveshowninchapter4.Moreover,asIhavearguedinchapters5and6,naturalselectionlacksanessentialfeatureneededtomakeitanalogoustoaneditingprocess.

ButPolanyi,Popper,andCampbellhavecriticizedmechanismatitsweakestpoint,forthereisacertainquestionthatnomechanisttheorycananswer,eveninprinciple.Considerthestrongestmechanicaltheory,Newtonianmechanics.

Thelawsofmechanicsarelawsofdevelopment.InthemechanicalphilosophyofNewtonandLaplace,theworld'sstateatonetimecompletelydeterminesitsstatesatallothertimes,past

andfuture.Therefore,inprinciple,theentirehistoryoftheuniversemaybereadoutofitspresentcondition,giventhebasicmechanicallaws.Nevertheless,eveninthistightlyconnecteduniverseanindeliblemysteryremains.Atsomepointanyexplanationoftheworldmustassumesomearbitraryfacts,namely,thestateoftheworldatsomedefinitemoment.Suchstartingassumptionsareusuallycalledinitialconditions,andtheyareoneexampleofwhatPolanyireferstoby"boundaryconditions."Thereisnoexplanationforsuchfacts.EveninaLaplaceanuniversealargemeasureofarbitrarinesspermeatesthefoundations.Theworldisthewayitistodaybecauseofthewayitwasyesterday,butwhywereyesterday'sconditionsastheywere?Becauseaninfinitenumberofworldtrajectoriesarepossible,thequestionremains,Whythisone?Anexplanationbymeansofefficientcausation,therefore,leavesmuchunaccountedfor.Forthisreason,anexplanationemployingformalcausationseemstofillaneed.Themarvelousandpuzzlingstructuresintheactualworld,wefeel,mightbeexplainablebypatterningagentsimpressingtheirformsonpassivematter.

Butthemechanisticexplanatoryschemebasedsolelyonefficientcausationneedsnosuchhelp,oratleastnotyet.Clearly,itsworkwillremainfarfromcomplete,butwecancatchaglimpseofwhatsortofanswertoexpectintheworkofIlyaPrigogineandhiscollaboratorsondissipativestructures(GlansdorffandPrigogine1971).Astheyhaveshown,amixtureofchemicals,formedbypouringvarioussolutionsintoacontainerwithoutanyadditionalconstraintsoninitialandboundaryconditions,maysortitselfoutandbegintoactasarudimentaryfeedbacksystem(seethediscussionoftheZhabotinskyreactionintheappendixofFaber1984).Makinganoptimisticextrapolationfromtheirwork,wemayexpecteventuallytobeabletounderstandhowthecomplexnetworksofcyberneticsystemsthatcharacterizelifecouldariseoutofthedissipativeprocessespresentin

theprebioticearth.Theextraordinaryphenomenonoflifewillthenbeunderstoodastheconsequenceofanyoneamongawiderangeofinitialconditionsthatarethemselvesquiteordinary.Ifthisreductionisticprogramshouldbesuccessful,itwouldstillbepossibletoretortthataphysical-chemicalexplanationoflifeismerelyanexplanationoftoday'sboundaryconditionsbyreferencetoyesterday's,whichremainunexplained.Nevertheless,the

antireductionisticthrustofthatreplywouldbeeffectivelyparriediftoday'sconditions,becauseoftheirremarkablecomplexity,demandanexplanation;andyesterday's,beingunremarkable,callfornone.

Popper,Polanyi,andCampbell,thoughtheirargumentsdifferinmanyrespects,seemtoagreethataphysical-chemicalexplanationoflifeisincompleteasacausalexplanation."Control,""editing,"and"downwardcausation"allconveytheflavorofcausalfactorsthatsupplementtheordinarycausationofphysicsandthatmustbeadducedasadditionalexplanatoryprinciplesifwearetogiveanadequatecausalexplanationofthephenomenonoflife.Butphysics/chemistryiseminentlysuccessfulatwhatitsetsouttodo;namely,totracethepresent,bymeansoflawsofdevelopment,fromthepast.Prigogine'sprogramhasagoodprospectofsuccess.

EightMentalEventsinPrequantalAtomism

RadicalAntireductionism

IntheprecedingchaptersIhavecriticizedontologicallyconservativeremediestomechanisticreductionism.Againsttheclaimthattheobjectivepictureoftheworldproducedbyscienceisjustoneofmanysociallyconditionedwaysofconstructinga"world,"Ihaveurgedthatthedisinterestedstanceofscienceisaprivilegedoneforthetaskofunderstandingthingsastheyareinthemselves,ontheirownterms.True,thescientificwayofrelatingourselvestomatterisoneofseveralpossibleattitudestowardthings.Technologicalexploitationisanother,andmorepopularatthat.Butscientificobjectivityisjustasmuchtobepreferredforthistaskasistheposturethatanthropologistsrecommendforunderstandinganotherculture:Wemustresistthetemptationtoincorporatetheobjectofstudyintoourowneconomy,values,orconcepts.Wemustconcedetoititsowninternaleconomy,itsnature,whichitisourtaskhumblyandrespectfullytoinquireinto.

Anddiagnosesofweaknessintheatomisticprogram,ofinabilitytowrestlewiththecomplexityoflivingorganisms,likewisefailtoproduceacure.Againsttheassertionofanirreduciblyhierarchicalstructureinourtheoriesandinnatureitself,Ihaveurgedthatnoneofthiscomplexityrefutesthereductionistthesisthatlivingthingsaredeterminedby,withoutinanysensedetermininginreturn,thenaturesandactivitiesoftheiratomicparts.

Iwanttosuggestthattheseproposalshavenotlocatedthecenterofthedisease.Theyprescribeforspecificpartsofreductivescience,butnoneisdesignedtostrengthenthemetaphysicalframeonwhichwefleshouttheatomisticstory.

InthisandthefollowingchaptersIshallofferaremedybasedonanotherdiagnosisofametaphysicalailment.Ishalldefendthethesisthatreductionism'sgeneralpictureoftheworldsuffersfromapinchedontology,whoserestrictiveinfluencecanbefeltinseveralvitalareas.Gettinganadequateinventoryofthekindsofthingsthatcarryouttheactivitiesthatoccurintheworldmustbeourfirstorderofbusinessaswesearchforareplytoreductionism.Ontologyholdsthesolutionbecausebyformulatingitwestipulatewhatwearewillingtorecognizeasreal.Therecognitionextendsbothtothethingsthatactandtotheactivitiestheyperform:NoteventhemostwhimsicalofmathematicianscouldimaginehowtheCheshirecat'sgrinningcouldcontinuewithoutthecatbeingtheretodoit.SupposethatsomeoneclaimstohavediscoveredanewphenomenonadeviationofthemotionofaplanetfromKepler'slaws,say,orextrasensorymentalpowers.Unlesswehaveanontologicalframeworkonwhichtohangtheallegednovelty,wewillbereluctanttoaccepttheclaimatfacevalue.Withoutapictureoftheworldthatallowsroomforadditionalastronomicalbodies,orthatoffersahintastowhatagentsmightcarryknowledgetothebrainwithoutgoingthroughthesenses,wewillprefertotrytoexplainawaythenewallegedphenomenonintermsof

atriedandtrustedontology.

Sciencehasagenerallytrustworthywaytomakesenseofnewphenomena,butitalsoimposeslimitsontheimagination.Inthestandardprotocol,anexplanationmustbecomposedintermsofmaterialparticlesandtheircausalinteractions.Eveniftheevidenceforastrologyweremuchstrongerthanitis,thescien-

tificallyproperattitudetowarditwouldbeoneofskepticismunlesswecouldplausiblyproposeamechanismbywhichtheplanetsexertuniqueinfluencesonindividualhumanlives.Withoutsuchahypothesis,responsiblescientistswouldlookforflawsintheevidenceortrytofindanotherinterpretationofit.Similarly,dependingonwhatmetaphysicalsystemweemploy,wemayormaynotbeabletoconcedethatmoralandaestheticjudgmentsormysticalexperiencesmakecontactwithreality.Limitedbyanontologyofatomisticmaterialism,weareobligedtoaccountinmechanistictermsforethics,aesthetics,andreligion.Wemustsay,forexample,thatsuchexperiencesarenothingmorethantheworkingsofneurologicalmechanismshard-wiredintothecentralnervoussystembynaturalselectionorprogrammedintoitbyschoolandfamily.Withamoreelaboratemetaphysics,however,morerealisticappreciationsofthesemattersbecomepossible;theyneednotbeexplainedaway.

Somehavesoughttodefendthevalidityofmysticaloraestheticexperiencebyrecommendingamoreflexibleepistemologicalstance,claimingthatscientificobjectivityisonlyoneofseveralcomplementarywaysofknowingtheworld.Butthisepistemologicaldiagnosiscannotstandbyitself.Itneedsontologicalsupport.Iftheworldmustindeedbeapproachedinwaysthatsupplementscientificobjectivity,thentheotherapproachesareneededbecauseofthenatureoftheworlditself,becauseofthevarietyandcomplexityofthethingsthataretobeknown.

Physicsisametaphysicallyladenenterprise.Itappliestheontologicalprogramofatomismtothebroadestpossiblerangeofexperience.Metaphysicalprograms,thehighestofallhigh-levelheuristicsforresearch,arenottestedbycrucialexperiments;theystandorfallwiththeprogressionordegenerationoftheirbroadprescriptionsformakingsenseofourexperiences.Hence,thesuccessofatomisticscience,especiallyinmolecularbiology,reflectsfavorablyuponthe

atomisticontology.Bythesametoken,ifatomisticattemptstoexplainimportantfeaturesofexperienceshouldfail,thensuspicionwouldsettleuponthemechanistphilosophy.

Theontologicalprogramofparticlephysicsformalizesauniversalactivitythatgrowsaswedeepenourunderstandingoftheworld.Earlyinlifewebecomeconsciousofourselvesasindividualbeings,distinctfromotherexistingthingsevenasweinteract

withthem.Allthesethingshavetheirownexistences,independentlyofoneanother,eventhoughcausallytheyareinterdependent.Partlybycontrastwithourexperienceofotherpersons,welearnoftheequallyindependent(thoughcausallyinterconnected)existenceofstillotherthings,whicharenotpersons.Material,nonpersonalbeingsalsobecometheobjectsofourattemptstounderstand.Ultimately,inphysicsweextendourattempttoreachbehindoursubjectiveexperiencestothethingsthatunderliethemandcausethem.Otherpersonsexist,certainly,butalso,wespeculate,somematerial,nonpersonalentities.Wehavefoundthattheseexistinlargenumber;wecallthemparticles.Thereachingbehindexperienceisnotdoneexperientially.Wedonotexperiencepersonsaswedosmellsorsounds,andwedonotexperienceatomssensuously,either.Thereachingisdoneintellectually.Itisagraspingperformed,hypotheticallyandtentatively,byspeculativereasoning.Thesuccessesofatomismhaveimpressedreductionisticthinkerssostronglythatmanyarewillingtolookforparticlesbehindevenourexperiencesofpersons.Indeed,atomismrequiresareductionofpersonhoodalongsuchlines.Astrongcasecanbemadeforit,andIhavetriedtodoitjusticeintheprecedingchapters.

However,Ishallattemptnoappraisalofethical,religious,andaestheticjudgmentshere.Alternativestothereductionistictreatmentofthosetopicscanbeentertainedonlygrudginglyunlesstheontologyofatomismisshowntobefaulty.Therefore,Ishallskirtthoseimportantbuttangledareasandconcentrateonjusttwoportionsofthemechanistworldpicturethatconnectcloselywithcurrentscientifictheorizing.Noteveryonehasbeenvisitedbyanuminousexperience,buteveryonehasconsciousexperiencesoftheordinary,sensorykind.And,althoughmanyentertaindoubtsabouttheobjectivevalidityofethicaljudgments,thescientificcommunityplacesmuchconfidenceinquantummechanics,thecurrentlyaccepteduniversalmechanical

theory.Ishallarguethatthephenomenaofconsciousnessandthepuzzlessurroundingwhatiscalledthemeasurementprobleminquantummechanicsbothrevealtheinadequacyofanontologyofmaterialparticlesalone;bothposeproblemsthatcanberesolvedbyenlargingourinventoryoftheworld'sfurnituretoincludemindsaswellasparticles.

EpisodesofconsciousnessareliketheCheshirecat'sgrin:

Somethingmustbedoingthem.Traditionaldualismsaystheyaredonebyminds.Atomismsaysthatnothingoccursthatisnotcarriedoutbymaterialparticles.InthischapterIshallarguethat,littleasweyetknowaboutthematerialsubstrateofsensoryepisodes,wealreadyknowenoughtoconcludethatnoportionofthehumananatomyperformsthem:Atomisticmaterialismhasbanishedthe"cat."Therefore,wemustchooseeithertodenythegrinningortotakeupdualismandrecallthecat.Inchapters9and10Ishallshowthatquantummechanicsrevealsacausalactivityforwhichatomisticmaterialismcannamenoagent.Again,dualismpromotesalikelycandidate.Suchaneminentlydubitablemetaphysicalplatformrequiresmorethanoneprop.Withoutsupportfromatomisticsciencetheintuition-basedargumentofthischapterwouldseeminconclusive;and,intheabsenceofapriorskepticismaboutthephysicalisttheoryofmind,enlistingdualismtomakesenseofthequantumtheorywouldlooklikebringinginamensexmachina;but,takentogether,thetwoargumentscomplementeachother.

Butwouldadualisticcurebeworsethanthereductionisticdisease?Manyphilosophersofmindwouldsayso.Certainly,dualismintroducesmanypuzzlesofitsown.Withoutslightingthem,Ishallsuggestinthefinalchapterhowwemightlearntolivewiththenewproblemswhileenjoyingthecurativeeffectsofamoregenerousontology.

TheGrainObjection

Topreparethewayforanextendeddiscussionoftheinterpretativeproblemspresentedbythequantumtheory,IshallfirstestablishaconnectionbetweentheatomistviewofthenatureofthingsandtheclaimsofCartesiandualism.ThecaseIshallpresentpivotsonadiscrepancybetweenwhatweknowaboutmentaleventsbydirectintrospectionandwhatatomismrevealsoftheessentialfeaturesof

anybrainprocess.Theargumentis,Ibelieve,thesameinessenceasoneproposedbyPaulE.Meehl(1966)andcriticizedbyMichaelB.Green(1979).Itdiffersindetailandmannerofexposition,however,inthatitmakesfulluseofthereductiveclaimsofatomismastotheformalstructureofanyprocessthatoccursinacompositething.

IagreewithGreen'sobservationthatthemerefactofsentience

castssuspiciononthethesisofmind-brainidentityand,indeed,ontheentireatomisticworldpicturethatrequiresustopostulatetheidentity.Monisticmaterialismchokesonsentiencebecausethereisnoroomforitintheatomistpicture.Otherpuzzlingphenomenadonotembarrassatomism:Whydolivingthingsexist?Whydoesthegoldfinch'sbillhaveitspeculiarshape?Howdodisplacedpetsfindtheirwayhomeoverunfamiliarterritory?Puzzlingthoughtheyareorhavebeen,atomismhasaplausiblestorytotellaboutthesequestions,oratleastaplausibleprescriptionforthesortofstoryonehopeseventuallytotellorwouldbeabletotellwithsuperhumanlydetailedknowledge.Butthereisanotherclassofallegedorimaginablephenomenaforwhichatomismcannotproduceaplausibleprescriptionforanunderstanding,forexample,allegedcasesofprecognitionoroftelekinesis.Andbecausewecannotevenimagineanatomisticaccountofsuchthings,wequiteproperlydoubttheirexistence.Sentiencefallsintothissecondcategory.Noonehasproposed,noonecanimagineastory,nomatterhowspeculative,thatwouldberecognizableasanatomisticaccountofsentience.How,forexample,diditfirstarise?Becausetheprimordialsoupcertainlydidnotandbacteriaprobablydonotsustainconsciousepisodes,andwedo,theabilitytoundergoorgeneratethekindofepisodetypifiedbysensoryexperiences,accordingtomaterialism,mustgraduallyhavearisenduringthecourseofevolution.Hence,anacceptableexplanationofhowsuchanextraordinarythingcouldcometoexistintheanimalkingdommustconformtothestandardsofevolutionarytheory.Butnaturalselectioncanpickoutonlylife-preservingorreproduction-promotingfeatures,andsentienceoffersnothingofthesort.Unconsciousautomatonswithnervoussystemsascomplexasourownwouldperformaswellinthestruggleforsurvival.Wemightspeculatethatsentienceisanincidentalbutphysicallynecessarysideeffectofsomeotherfeaturethatdoespromotesurvivalthemostlikelycandidatebeingtheabilitytobehaveintelligently.Butthatconjecture

seemsmostunlikely,becausemostofwhatgoesoninthebrainoccurswithoutanyhintofconsciousness,evensomeintricateexamplesofintelligence.Talesaboundofmathematicalorscientificproblemssolvedbythesleepingbrain,theanswerdeliveredwholeandpolishedtoconsciousnessinthemorning.Thesolutiontoachessproblemorananagrammayspringsud-

denlyintotheconsciousmind,obviouslyhavingbeenworkedoutbyintelligentbutnonconsciousmechanisms.C.S.Forester(1964,pp.65,66)tellsofelaborateportionsoftheplotsofhisnovelsbeingpresentedtoconsciousnessbysuchhiddenfactories.Clearly,themechanicalbraincanhandlemathematical,logical,andcreativetaskswithouttheaidofconsciousness;whatbiologicalfunction,then,canithave?Whyshouldnoteverybrainprocess,fromtheleasttothemostintelligent,proceedequallymechanically?Indeed,consideringtheextremeyouthofbrainscience,wehavelittlereasontodoubtthatplainneuronalmechanisms,notvarnishedoverwithsentience,canaccountquitewellfortheovertbehaviorweseeinotherpersons.How,then,couldsentiencehavecometoexistinthecourseofevolution?Andhowcouldthatghostlyhanger-onhavegiventothesurvival-promotingbehavioroftheanimalanextrafeaturethatnaturalselectioncouldhavelaidholdof?YettheresentienceisareproachtotheDemocriteanontology.Allwecandoisgesturevaguelytowardtheyouthfulscienceofneurophysiologyandvoicethepioushopethatsomethingwillturnup.

Althoughconsiderationssuchasthesefuelskepticismabouttheidentitythesis,theycandonomorethanpromptustoseekadefinitiveargument.GreendoubtsthepossibilityofformulatingaconvincingrebuttaloftheidentitythesisbasedonLeibniz'sprinciple.Sucharebuttalwouldestablishacleardiscordancebetweentheknownpropertiesofatypicalmentalepisodeandthoseofanycerebralprocesswithwhichitmightplausiblybeidentified.

Greenpresentsasympatheticoutlineofwhathedubs''thegrainobjection"tothemind-brainidentitythesisbutfinallyrejectstheobjectiononthegroundsthat"intersubjectivestructure,thoughmind-independent,doesnothaveaperspective-freefocuswhichpermitsittobedeclaredeither'grainy'or'smooth'toutcourt"(1979,p.586).Now,Ithinkthisskepticismisunjustified.Greenseemstoassume

thatourvariousscientificandcommonsenselevelsofdescriptionarequitearbitrarilychosen,thatthemacroscopicoverviewwemaytaketowardacompositething,inwhichwelosesightofitsatomicconstitution,isneitherlessnormorefaithfultothewaythingsarethanamicroscopicdescription.Both,asGreenseemstoevaluatethem,aremerely"perspectives"thatweadoptforonereasonoranother.Suchan

egalitarianassessmentofthesemodesofdescriptionmightbejustifiedifeachbroughttolightsomefactsthattheotherobscured,ifeachweremerelyapartialaccountofthenatureofthingsthatneedstobesupplementedbytheother.IhavecriticizedthatsortoflaminarrelativisminmydiscussionofRyle'sdefenseofthelanguageofcommonsenseagainsttheclaimsofatomicphysics.ThereIarguedthattheatomistic,lower-leveldescriptioninprincipleobscuresnothing,hencealwayslegitimatelyclaimsgreaterin-principlefidelitytoobjectivetruththananyupper-levelaccountcanboast.Thesubsequentdiscussionoffunctionalismwasdesignedtomakegoodthatreductionisticclaimforanespeciallychallengingexampleofupper-leveldiscourse.Accordingtotheatomistreductionprogram,thereissomewhere,waitingtobefound,aperspective-freeaccountofthewaythingsare.Infact,todenythepossibilityofsuchadescription(denyingthatwecanbesurethatwehavefinallyachieveditis,ofcourse,quiteanothermatter)istorenouncetheprogramofobjectivescience.Havingarguedforthisunderstandingofthescientificprogramabove,IshallsimplyassertherethatItaketheaimoffundamentalsciencetobeanunderstandingofmaterialthingsthatacceptsthemontheirownterms,notbendingthemtoparticulardesignswemayhaveonthem,nottreatingthemasadjunctsofourownconcerns,notviewingthemfromthisorthatsubjectiveandlimitedperspective,butacceptingthemastheygoabouttheirownaffairslargelyheedlessofourselves,astheyalsomovedandinteractedbeforehumanbeingsstrodeontotheworld'sstage.Green'scriticismsofthegrainobjectionarenotfatalones.

Infact,theobjectionisespeciallyappropriatetothisdiscussionofatomisticreduction.Ishall,therefore,presentaversionoftheargumentbutwithseveralalterationsIconsideressentialforclarityandeffectiveness.

RestrictionsontheArgument

OtherMinds.

Consideringitsuniquetopic,itshouldnotbesurprisingthattheargumentpresentsseveralunusualfeaturesandraisessomepeculiardifficultiesofexposition.Threedistractingissuesmustbeseparatedfromtheoneathand.First,thereisthequestionofwhetherwecanknowthatothermindsexist.The

answeristriviallyyes,ifwehavealreadyestablishedthatmindsareidenticaltobrains,butotherwisetheanswerisnotsoobvious.Sowemustposethequestionofmind-brainidentityinawaythatdoesnotassumesuchaneasyanswertothequestionofothermindsotherwise,wewouldbegthequestionatissuehere.Letusassumenomorethanisheldincommonbythecompetingtheoriesaboutotherminds.Howevermuchtheymaydisagreeaboutthepossibilityofaccessbyotherpersons,thecompetitorsbothassumethatthepersonhasaccesstohisownmentalepisode.Hence,wegetthisdecidedlypeculiarfeatureofthegrainobjection:Itmustbeaddressedpersonallytothereader;Imustaskyoutoconsideryourownmentalepisode.Becauseatthisstagewecannotfairlyspeculateabouttheexperiencesofathirdparty,eachpersonmustapplytheargumenttohisorherownexperience.

TopicNeutrality.

ThegrainobjectioncannotbestatedwithoutrejectingJ.J.C.Smart's(1962)proposaltocastthequestionin''topic-neutral"language.Smartinvitesustotreatamentaleventaswhatevergoesoninourselves(weknownotwhatitis)thatiscausallyresponsibleforpainbehavior,verbalreportsofaninnerstate,andothermanifestationsofmentality,includingovertbehaviorandcoverttendenciestobehave.Ifweshouldacceptthisinvitation,wewouldhavetolocatementalitywithinthenetworkofphysicalcauses,forthosehiddenspringsofhumanactionsarelikelytoberevealedbyneurologicalexperimentsasfiringsofnervecells.AndSmartasksmorethanthat.Inhisview,onementaleventcanbecomparedtoanotheronlybyournotingdifferencesandsimilaritiesintheverbalandotherexpressionstheyimpelustomake.Expressingallthatweknowaboutamentalevent,onewouldsay,intopic-neutrallanguage,"SomethingisgoingoninmethatislikewhatisgoingonwhenIlookatMcIntoshapples,blood,asunset,andsoon.HowdoIknowthatit'slikethoseother

goings-on?Ifindmyselfrespondinginthesameway."Ifthatistheonlysortofaccesswehave,thenasownersofmentalprocessesweknownomoreaboutthemthanwhatwehearourselvessayinginaudibleutteranceorinternalmonolog;hence,weareinessentiallythesameepistemologicalpositionasisanexternalobservertopronounceonwhattheyarelike.Fortheowner,too,mentaleventsarethenthe

hiddencausesofovertbehaviorortendenciestobehave,eventstowhichhehasonlyindirect,inferentialaccess.However,thegrainobjectionstipulatesthattheownerhasknowledgethatsupplementswhatisobtainedbytheclinicalpsychologistorthephysicist.Isthataplausibleassumption?Herethereadermustdecideforhimselforherself.Speakingformyself,Ifindthattheexperienceofrednessisbothwellknownandpeculiar,quiteunliketheuniqueexperienceofyellownessorofatoothache,andthatallofthemarericherthanmyverbalutteranceshaveeverindicated.Idoindeedknowwhatthesmellofnitrobenzeneislike,independentlyofthecomparisonsIhearmyselfdrawingbetweenitandotherexperiences.Iconcludethattopic-neutrallanguageisnotissue-neutralinthiscase,andIshalldeclinetheinvitationtouseit.

SpuriousSpatiality.

Comparedwiththesefundamentalrestrictionsontheargument,thefinalmodificationIwishtomakeseemstrivial,butitdoes,Isubmit,promoteanimportantincreaseinclarity.Itisatemptingandmisleadingerrortodrawourexamplesfromvisualexperience,asmanyauthors,includingMeehlandGreen,do.Theproblemwithvisionasaprovinggroundfortheoriesaboutmind-bodyrelationsisthatitissocloselyconnectedtospatiality.Theconnectionleadsustotakeuncriticallythecommonsensebeliefthatspaceasweexperienceitisanobjectivestageorcontainerfortheactivitiesofthematerialobjectsthatdotheworld'swork.Thatassumptionbestowsuponvisionafalseauraofobjectivity.Asexperienced,space-timebelongsprimarilytothephenomenalrealm.Themostwecandotoreachbeyondittotheworldofobjectsistointerpretphenomenalspace-timeasamanifestationofintrinsiclimitsinthecausalinteractionsthattakeplaceamongthematerialobjectsofourknowledge.Wemaytrytosubdividetheroundredpatchofanafterimageintosmallerredwedgesandbegintofeelconfusedastojusthowfartocarrythis

mentalcounterpartofrocksmashing.Time,ontheotherhand,doesnotsimilarlysteerusintobyways,becausetemporalcross-sectionsofenduringobjectsdonotcountascomponentpartsevenwithinthematerialsphere.Whateverpartswemayadmitmustbethemselvesenduringthingsoractivitiescarriedoutbyenduringthings,nottemporalslicesofthem.Space,nottime,exertstheattractiontoward

befuddlement.Therefore,asaprototypeofa"rawfeel"Ishalladoptthesortthatisnotnormallyconnectedtospatiality:notavisualbutanolfactorysensation.

Asmellsensation,thoughitlacksspatiality,neverthelesshasanidiosyncraticrichnessofitsown,allthemoreusefulforourpresentpurposebecauseitisnotoverlaidwithautomaticconceptualinterpretation,atleastnottothedegreethatvisualandauditorysensationsare.Muchmoreeasilythanwhenexperiencingtheseothers,wecanattendtothesmellsensationitselfwithout"lookingthrough"ittoitssourceintheworld.

CharacteristicsofSensations

Inowsetdown,asaxioms,threecharacteristicsofsensationsingeneralandoneofsmellsensationsinparticular.Itakethemtobeself-evident.Whethertheycommanduniversalassentornot,theyareessentialtotheargumentthatfollows.

First,anexperienceisnotathing,suchasaneuron;notapropertyofthings,suchaselectriccharge;notarelationbetweenthings,suchasspatialcontiguity.Itis,rather,aconcreteepisodeinthelifeofasentientbeing.By"episode"Imeanatemporallyextendeddoingorundergoing,engagedinbyoneormoreenduringobjects.Oneperiodofahockeygame,acatsmiling,andagasexertingpressureduringathree-secondinterval:theseareepisodesinthehistoriesoftheactiveentities.Anepisodeisnotthedoerapartfromtheactivity,ortheactivityintheabstract(neitherthecatitselfnoritsdisembodiedsmile);itis,rather,aconcreteinstanceofsomethingdoingsomething.Now,iftheatomistreductionthesisiscorrect,anyepisodeofacompositethingistheconcurrenceoftheindividualactivitiesofitsparts,thesimplesumofthecomponentepisodes.Thegaspressingagainstitscontainer,forexample,isnothingmoreorlessthanthe

moleculesofgasandbottlebatteringoneanother.Acompositething,accordingtotheatomistthesis,isrunbyitsparts;anythingitdoesisdonebythem,anyepisodeitundergoesisabundleoftheirepisodes.

Second,Ishallassumethatasensoryepisodepreservesatleastsomeformalandnumericalcharacteristicsofwhatunderliesit,howeveritmaydifferfromtheobjectinotherrespects.Philosophicaltraditionsdivergewidelyastohowmuchweknow

abouttheintrinsicnatureofanexternalevent,butallthatstandthissideofutterskepticismagreethatwecanknowatleasttheformalstructureoftheexternalworld.ThetwonessofAlice'sexperienceofTweedledumandTweedledeeaccuratelyreflectsarealtwonessinherperceptualapparatusandintheTweedlefamilyitself,howeverunlikethesubjectiveandobjectiveoccurrencesmaybeinotherrespects.Nodoubtmoreelaboratestructuralisomorphismsalsoobtain,butthissimplematchingofcomponentepisodeswillsufficeformyargument.Multiplicityinanexperienceimitates(accordingtodualism)orisidenticalto(accordingtomaterialism)amultiplicityofprocessesinthecerebralcortex.

Green,however,deniesthisclaim.Hesuggeststhatastructuralfitbetweenamentalepisodeandtheexternalobjectofknowledgemightbeachievedinsomecasesbyachainthatmerelyconveysthestructurewithoutitselfembodyingitateachintermediatestage.Hesupportsthisconjecturewithananalogy,theconveyingofthestructureofapoembyamessagethatencodesmerelyapagereferenceandtheLibraryofCongresscallnumberforabookinwhichthepoemisprinted.Butthisanalogyisunconvincing,becauseeveninthiscasethestructureisinfactconveyednotbythereferencealonebutbyitinconjunctionwiththebook,whichdoesembodythestructure.Examiningtheentiremechanism,wefindthatthecausalchaindoesconveyastructurebyexemplifyingit.And,bethatexampleasitmay,thealternativeGreenproposescouldnotariseundertheidentitythesis,simplybecausethereisthennoquestionofacerebralprocessconveyinganythingtoconsciousness,withorwithoutexemplifyingit;thecerebralepisodejustistheconsciousepisodeandhencemustexemplifyits(own)structure.

Third,becausethegrainobjectionconcernsknowncharacteristicsofmentalepisodes,itisnecessarytobeclearaboutthenatureofourknowledgeofthem.Ishallassumethat,althoughwecanthinkabout

sensationsobjectively,wecannotscrutinizethemwiththesamedegreeofdetachmentthatwebringtobearuponotherobjectsofknowledge.Thatkindofseparationisimpossiblebecausetheattentionwepaytoasensationisintegraltotheexperienceitselfandhelpstodetermineitsquality.Therearenottwoactivities,theundergoingofasensationandtheundergoingofanawarenessofit,butjustone.Thisepisodediffers

fromother,trulydoubleactivitieswemayengagein,suchasthecombinationofstubbingone'stoeandundergoingapainsensation.Wecannotsplitamentalepisodealongthelinesofthedistinctionbetweenobjectandappearance.Whenwe"look"at,notthrough,asensation,theobjectincludesitsownawareness.Suppose,forexample,thatapersonuntrainedintheappreciationoffinewinessavors,atthebeginningofacourseofstudy,aglassofLafite'23.Yearslater,morelearnedintheloreofthevine,shesamplesthevintageagain,nownoticingmuchmoreaboutthesamewine.Butwoulditbecorrecttoclaimthatshenoticesmoreaboutthesameexperience?Itakeitasanaxiomthattheanswerisno;thelaterexperienceisanewone,richerandmorecomplexthantheearlier.Atthetimeofthefirstsamplingtherewasmuchaboutthewinethatthenovicefailedtonotice,butnothingwentunnoticedintheexperience.

Wecannotapplytothespecialcaseofconsciousexperiencestheotherwiseusefuldistinctionbetweenappearanceandreality.Wecannotsay,forexample,thatasubjectiveexperienceonlyappearstobesimplebutisreallyfullofunsuspectedcomplexity,fortodosowouldintroduceonestagetoomanyintheprogressionfromthingstotheirappearances.Thementaleventis,bydefinition,theproceedingthatmakesupthelaststageinthesequence.Wehaveappearancesofthingsbutnotappearancesofappearances:Theyarenotviewed,imperfectly,byalurkinghomunculus.Theexperienceiswhatitappearstobe.Forthesamereasons,IshallrejectthehypothesisproposedwithoutmuchenthusiasmbyGreenasapossibleinterpretationofsomestatementsofFeyerabend(1963),namely,thatamentalentityhasallthepropertiesrequiredbytheidentitythesis,andthosepropertiesareinfactexperienced,butourspeechandother"tokening"mechanismssubvertusintoutteringlessthanthetruth,sothatwemakefalseclaimsaboutunitarityandsmoothness.Accordingtothishypothesis,wecometobelievethatmentalprocessesare

radicallydifferentfromphysicalonesthroughlisteningtothesedeceptiveutterances,orattendingtotheinteriormonologsthatprecedethem.Irejectthisconjecturebecauseitseemstomeobviousthatspeech,overtorinternal,doesnotmakeexperiencebut,rather,followsit.Firstwehaveanexperience,richlyandself-consciously;thenwesearchforwordstoexpressit.Theexpressionisusuallyfarfromperfect,butwecancriticizeitby

holdingitupagainstfurtherexperiences.Itdoesnotinsinuateitselfbetweenusandourmentalevents.Noveilofanykindhangsbetweenusandourexperiences.

TheComplexityofSensations

Finally,letusinquireastothecomplexityofanolfactorysensation.Whatarethecomponentpartsofsuchanepisode?Imagineaquiteunprecedentedsmellexperience,asmightbehadbyachemistwhohasjustsynthesizedaneworganiccompound.Howmanypartshasit?Onefeelsinitiallyatalossastohowtodividesuchanepisodeintopartsofanykind,butwemayattributethisinitialbafflementtothenonspatialcharacterofolfactionandourunreasonablebiastowardgeometrywhenwespeakofparts.However,ifpartstheremustbe,wemayperhapsidentifytheoccurringofcertainqualitiesascomponentsinthesinglesmellepisodequalitiesofthesortthatusuallygounnoticedinordinaryexperienceandthatwinetastersandperfumersinventnamesfor.Howmanyqualitiesmakeupasinglesmellepisode?Thatdependsontheexperiencer'sattentiveness,skillindiscriminating,andstateofhealth.Iaminclinedtoclaimthatthesmellepisodeexperiencedbyanuntrainedperceiverisabsolutelyunitary,sothatsuchanolfactoryexperienceconsistsofexactlyonepart.ButthisversionofthegrainobjectionwillstandifIconcedemoreinthedirectionofmultiplicitythaneventhemostdiscriminatingoenologistmightrequire.Letussay,extravagantly,thatinthenostrilsofanexpertsomesmellexperiencesmayconsistofthesimultaneousgoing-onof100discriminatedqualities,100componentepisodes.

Justwhatareweawareofwhenwepayattentiontothequalifiesofanodor?Accordingtomonisticmaterialismwearemakingdirectcontactwithacerebralepisode,anactivityperformedbyapartofthebrain.Normally,weknowsuchthingsonlyindirectly,bythemediationofasensoryapparatusthatgeneratesothercerebralepisodes,whichare

themselvesnotidenticaltothesmellexperienceandwhichwemustinterpretbymeansoftheconceptsandtheoriesofscience.Buthereinthiscombinationofqualitiesandattentivenesstothemwehavetheprocessitself,bare,unmediatedbythesensoryorgansorbyconceptualinterpretationnotamentalconstructofanotherthingbutthething

itself.Forhowcoulditbeotherwise?Ifallwehadwereanappearanceofthesmellexperience,thentheidentitythesiswouldhavetoapplytothisnewimage,andthesortingoutofappearanceandrealitywouldrecurendlessly.No,theprocessofgeneratingasensationmustterminateinaperfectlydefiniteepisodethatrevealsitselfutterly.

Nevertheless,ourmediated,sensoryknowledgeofthissameepisode,hypotheticalandindirectthoughitbe,doespreservetheformal,quantitativefacts,orsowemustbelieveifweacceptthereductionprogramofatomism.Amongthosefactsisthis:Atypicalconsciouscerebralepisodeconsistsofmanythousandsofneuronssimultaneouslyfiring,ofhordesofneurotransmittermoleculespassingbetweencellmembranes,ofcountlessmigratingionsofpotassiumandsodium.Butlettheargumentproceedafortiori:letustaketheabsoluteminimumconceivableforanycerebraleventthatmightbeidentifiedwithaconsciousepisode,asinglenervecellfiring.Aneuronfiringisnotaunitaryeventeither;eventhisepisodeiscomposedofthesimultaneousrunningoftheindividualactivitiesperformedbyeachmaterialpartofthecell.Andbyaconservativeestimatethepartsnumbernotlessthanabouttentothefifteenthpower.Soanyneuronaleventconsistsofatleastthatmanyconcurrentindividualepisodes.

Hereisaglaringdiscrepancy:Fromthephysicaldescriptionwegetacountoffifteenpowersoftenormore;fromthesubjectiveexperience100ormuchless.Cantheatomisthypothesistoleratethatdiscrepancy?Alackofaccordoversomefeaturesofmentalandphysicalepisodeswould,ofcourse,beconsistentwiththeidentitythesis.Wecannotexpectthephysicaldescriptionofaprocess,theviewfromoutside,asitwere,actuallytoconveyitsinnerreality.Letusallowaverywidemarginforthatsortofdiscordance.Forallweknowtothecontrary,whatweconceiveoffromtheoutsideasa

certainpotassiumiondiffusingthroughaneuron'smembranemayjustbe,initself,theuniquegustativeepisodethatwinetastersrefertoasthesensationof"flintiness."Butthereisonesortofmismatchthattheidentitytheorycannottoleratebecauseitwouldentailabandoningtheatomistprogram,namely,adisagreementastoformalstructure.Anessentialelementintheformalstructureofanepisodeisthenumberofthecomponentepisodesthatmakeitup.Inordertodiscoveradiscrepancyoverthiselementofformwedonotneed

tomakeanyquestionableassumptionsaboutwhataphysicallycharacterizedepisodeisreallylikeontheinside;allweneedtodoiscount.Andtheresultisthis:Acerebralepisodeconsistsofamyriadofindividualdoingsandundergoingsbyascarcelyimaginablenumberofmaterialobjects,whereastheexperienceconsistsofafairlysmallnumberofcomponentepisodes,namely,thetemporaryoccurringofafewolfactoryqualities.

Letustrytoexplainthisdiscrepancy.First,wemightquestiontheallegedmultiplicityofthecerebralepisode.Canwetrustthephysicaldescription?Sometimesweerrincounting,skippingoveranitemwhilerecitingtheintegers.Itisatleastthinkablethatsomeimportantfactsaboutthematerialepisodehaveescapedournotice.Therefore,thephysicalepisodemaybemoreelaboratethanthephysicalstorymakesitouttobe,butitcannotbelessso.Or,second,ifwethinkofthementalepisodeasamereresultofthebrainprocess,andthusnotidenticaltoit,thenwemightexpecttheeffecttobelesscomplexthanthecause;informationisusuallydiminishedasamessageistransmittedfromonestructuretoanother.Butthisrejoindersucceedsonlybyabandoningtheidentitythesis,becausearesultisdistinctfromitscause.Third,wemighttrytoidentifyeachcomponentepisodeoftheolfactoryexperiencewithanaturalgroupingofthecomponentsofthebrainevent,identifyingtheoccurringofonequality,forexample,withthefiringneuronsinonesmallregionofthebrainandanotherwiththegoings-oninaneighboringregion.Butweprogressnotatallbythisstratagem.Westillhaveamultiplicityinthephysicalepisodethatexceedsbyfarthemultiplicity(infactasingularity)ofthementalone.Thephysicalepisodecannotbelesscomplexthanneurophysiologyorchemistrypicturesit,andthementalepisodecannotbemoreelaboratethanweexperienceittobe.Hence,theallegedlyidenticalepisodesdifferwithrespecttoaformal,essentialproperty.Noneoftheseapologieswillwork.

Wehaveuncoveredadilemmaatthecoreofthematerialistreductionprogram.Atomismrequiresustoadopttheidentitythesis,butwehaveseenthatanexperience,whichmustbethenakedfactofthephysicalepisode,failstoconformatacrucialpointwiththepicturewehaveformedbyfollowingtheprogramofatomisticscience.Eitherobjectivescienceutterlymisrepresentstheonefeatureofmaterialprocessesthatitmustnotmiss

theirformal,numericalstructureortheexperiencefalsifiesitself.Eithertheontologicalprogramofsciencefailstodeliverthegoods,oranappearanceisnotasitappears.Thefirsthornwouldemptytheidentitythesisofitsontologicalcontent.Ofwhatsignificancewoulditbetoasserttheidentityofmindtomatterifwecannottrustwhatsciencetellsusaboutthenatureoftheright-handsideoftheequation?And,asIhaveurgedabove,thesecondhornisnecessarilyfalse.Neitheralternativeisacceptable;hence,theidentitythesisisdemolished.Hence,thementalepisodeisnotcarriedoutbymaterialparticles.Becausenophysicalobjectpresentsitselfforthattask,Iconcludetentativelythatitisadistinctactivity,donebyadistinctperformer.Theworldismadeupoftwobasicsortsofstuff.

FurtherProblems

Bynomeansdoesconcludingfordualismputanendtopuzzlement.Itopensout,infact,atangledfieldforexploration.Wealreadyhaveafairlylargesetofunexplainablegivensaboutmatter,suchasthebasicstructureofmechanics,thefundamentallawsofinteraction,andarbitraryfactsaboutthenumbersandkindsofparticlesthatcomposetheworld.Nowwemustaddsomebasic,equallyunexplainablefactsaboutmentalentities:whattheyare,howtheyparticipateincausalinteractionsamongthemselvesandwithmaterialparticles.

Someprofoundquestionsplaguethedualistconjecture,andwedowelltofacethem,evenifwemustleavethemlargelyunresolved.Theyaremademoredifficultbecause,inattemptingtothinkaboutthementalasadistinctontologicalcategory,wehaveapowerfultemptationtodrawanalogiesfromwhatweknowofthematerialrealmandforcethemuponourembryonicunderstandingofthemental.Itwouldbeamistake,forinstance,totrytotranslatetheentireprogramofatomisticanalysisintomentalterms.Asapreliminaryattempttoavoidthaterror,letustaketheunitarymental

entitytobeamindandclassifysmellsandafterimagesnotascomponentpartsofmindsbutamongtheactivitiesthatmindsperform.Buteventhisplausiblesuppositionleavesmuchunsettled.What,forexample,couldanactivityamounttoinamentalsubstance?Weknowhowtoanswerthatkindofquestionformaterialthings.Anyphysicalprocessulti-

matelyconsistsofjusttwosortsofoccurrences,motionandtransmutation,whichareexemplifiedbytheflightofamuontowardtheearth'ssurfaceanditsdecayintoanelectronandaneutrino.Internalprocessesincompositethingsconsistalmostwithoutexceptionofrealignmentoftheparts.Buttheseexamplescandonothingtoaidushere.

Perhapsthemostperplexingquestionisthis:Howcanweunderstandthecausalinteractionbetweenmindsandparticles?Whatconceptualapparatuscanwehammertogetherfor,clearly,theconceptsofforceandmotionprovidenohelptomakesenseoftheabilityofaportionofthebraintocauseamindtoperformasensation?Andhow,ifatall,canawilling,choosingmindaffectthemindlesssurgingofparticles?Canamindpushuponaparticle,causingittoswerveoutofthepathitotherwisewouldhavetaken?Mostoftheuniversehasnotrafficwithconsciousness,oranyneedofit.How,then,isitpossibleforthemindassociatedwithahumanbraintoinfluencethecourseofeventsinthecerebrum?Forexample,bywhatmeanscanthespeechmechanismofthebrainbecausedtoreportamentalevent?How,ifmatterrunsonitsownwithoutinterferencefromanothersphereofbeing,couldtheideaofthatotherspherebecomeencodedintheconnectionsoftheneurons?

Asweshallsee,adualisticinterpretationofquantummechanicsthruststhesequestionsunderone'snose.However,asIshallattempttoshow,italsohintsatthepossibilityofanewkindofanswertosomeofthem,ananswernotimaginablewithintheconceptualframeworkofNewtonianphysics.

NinePotentialityintheQuantumTheoryHowcanweprovidetheoreticalsupportforourdeep-seatedintuitionthatmacroscopicobjectshumanbeingsespeciallyparticipateintheworld'saffairsasunitaryagents?Thetasklooksdifficultbecauseoftheportentoussuccessesofatomisticscience,whichclaimstoaccountforthecausalactivityofanycompositethingasnothingotherthantheconcertedactivitiesofitsparts.IntheearlychaptersIhaveignoredpossibleanswersthatwouldchallengeamaterialistontology.Thoughnotalloftheantireductionisticargumentsconsideredtherewereadvancedbyadherentsofmechanisticmaterialism,allareconformabletoit.Quantummechanics,however,opensanewlineofinquiry.

Twofeaturesofthequantumtheoryseemtorequireustofaceradicalquestionsabouttheplaceofmindinaworldofatoms:Thefirstisthetheory'sunprecedentedtreatmentofprobability;thesecondisauniquelyquantum-mechanicalphenomenon,commonlycalledthereductionofthewavepacket,associatedwithobservationandmeasurement.Inaddition,whetherornot

allegationsofmentalismcanbesubstantiated,athird,closelyrelatedchallengetoatomismstillwouldstand:someexpositorsofquantummechanicsfindinitanovelsortofinterconnectednessamongthepartsofcompositesystems,afeaturethatdeservestobecalledquantum-mechanicalholism.Letussee,first,howreferencestoprobabilityinafundamentaltheorymightraiseaformidablebarriertotheatomistreductionprogram.

Themechanisticpictureoftheworldentailsthephysicalisttheoryofmind,whichidentifiesaconsciousexperienceasnomorethanaprocesshighlyplacedonthereductionistladder.Theultimatetruthaboutsuchanexperience,likethetruthaboutanyotherupper-levelevent,istobetoldinastoryaboutatoms.Inourpresentstateofunderstanding,wemustnarratesuchstoriesinthelanguageofthequantumtheory.Quantummechanics,unliketheNewtonianvariety,assignsprobabilitiestothepossibleoutcomesofexperiments;itdoesnotdeterminedefiniteresults.Buttalkofprobabilityinafundamentalphysicaltheoryraisesaproblemfortheatomistprogram.

Accordingtoonecommoninterpretation,probabilityranksthedegreeofconfidencewithwhicharationalobserverexpectstheeventtohappen;accordingtoanother,probabilitymeasurestheconsonancebetweenapropositionanditsevidence.Now,ifprobabilitymustbeunderstoodintermsofknowledge,expectations,orthemakingofpropositions,hopeforacoherentlyatomisticunderstandingofconsciousnessfadesaway.Consciousness,treatedasanupper-levelevent,wouldbeexplainedbyastoryaboutatomsandtheprobabilitiesoftheirbeingincertainstates,andtheseprobabilitieswouldturntheexplanationbacktoitemsofhumanthought.Takingquantummechanicsasthebasictheoryofmatter,wewouldfindthatconsciousnessliesattheheartofreality,notattheperipheryasthereductionistprogramrequires.Therefore,sothisargumentgoes,thematerialistprogramfordealingwithsentiencesuffersfromvicious

circularity.

Thisthreattoatomismrestsonthreeassumptions:thatatomismbuildsonarealistviewofphysicaltheory;thatquantummechanics,exceptforpossiblerefinements,speaksthefinalwordaboutphysicalreality;andthatprobabilityentailsissuesofthoughtandlogic.Assciencestands,wecouldnotabandonrealismwithoutgivingupatomism,too,nordowehaveatpresentaseriouscontendertodisplacequantummechanicsfromits

fundamentalpositionintheedificeofnaturallaws.However,anatomistmightspeculateaboutalternativeinterpretationsofprobabilitywithoutendangeringthecoreoftheprogram.WernerHeisenberg(1958)electsthisdefensivegambit,suggestingthatinquantummechanicsprobabilityrepresentsarealpropertyofexternalobjects,possessedbythemindependentlyofwhatwemayknoworsayaboutthem.AccordingtoHeisenberg,theconceptrefersnottoitemsofknowledgeortorelationsamongpropositionsbuttomultiplepossibilitiesobjectivelypresentinmaterialthings.Thisinterpretationretainsanimportantfeatureofscientificrealism,becausepossibilitiesthatobtainobjectivelywouldcontributetheirpluralitytothestructureoftheworldapartfromhumanconsciousness;thus,thetheorywouldapplyinprincipletoepochsthatantedatetheappearanceoflifeontheplanet,asanyobjectivetheoryshould.

However,Heisenberg'sobjectiveinterpretationofprobabilityinvitesasecondmentalisticchallenge(see,e.g.,Wigner1961).Ifpossibilitiesexistobjectively,thenanyreductionintheirrange,ofthesortassociatedwiththeprocessofmeasuring,isalsoanobjectiveevent.Heisenbergcallssucheventstransitionsfrompotentialitytoactuality.Butthecauseofthemhasbeenthesubjectofcontroversyamonginterpretersofquantummechanics.AsuggestionmadebyErwinSchroedinger(1935)placestheresponsibilityforthetransitionontheactionofmind;Heisenbergattemptstoproduceapurelymechanicalaccountoftheprocess.IshallarguebelowthatHeisenberg'sattemptdoesnotsucceed.

Withfortunateconsequencesforthelengthofthischapter,thephilosophicallygermaneissuesraisedbyquantummechanicscanbeexhibitedmainlybydescribingtypicalphenomena,withlittleornoreferencetothemathematicalstructureofthetheory.Accordingly,Ishallpresentthetheorybymeansofparadigmaticexperiments,showingthattheyrequireustobringanovelconceptofpossibilityto

bearuponthephysicalworld.This,Ishallurge,isthewaytoemployHeisenberg'snotionofpotentiality.

AfterintroducingHeisenberg'sgeneralstrategyaspartofaprogramtointerpretprobabilitiesrealistically,Idiscussthebehaviorofsingleatomicparticles,principallyinthedouble-slitexperiment.Thesephenomenachallengeustofindacoherentlanguagefordescribingquantumphenomena.Tomeetthechallenge,IrecommendamodallogicthatemploysHeisenberg'spo-

tentialismandthatIinterpretbymeansofphysicalpossibility.Iturnthentoauniquelyquantum-mechanicalphenomenon,thetransitionfrompotentialitytoactuality,whichisallegedtooccurinthecourseofameasurement,illustratingitwithanotherparadigm,Schroedinger'sthoughtexperimentconcerningacatplacedinperilouscircumstances.Finally,IdescribetheEinstein/Podolsky/Rosen''paradox,''inwhichapairofatomicobjectsundergocorrelatedtransitionstoactuality,exhibitingthepuzzlingphenomenonofnonlocality.

Myreview1oftheparadigmsofquantummechanicssetsthestagefortheprincipalbusinessofchapter10,namely,assessingantireductionisticargumentsbasedonthenatureofthetheory.Iconsiderthreefeaturesofquantummechanicsthatseemtochallengethepremisesofatomism:nonadditivity,nonseparability,andtheallegedintrusionofconsciousnessintothemeasuringprocess.Iarguethat,highlyspeculativethoughitis,onlythelastpromisestodeliverasatisfactoryanswertoatomism'sattackonourintuitionsabouthumancausalagency.Chapter11concludeswithsomecautiousspeculationsabouttheplaceofmindintheorderofnature,therebydemonstratingwhatispermitted(thoughcertainlynotrequired)bythequantumtheory'sunprecedentedtreatmentofconsciousness.

NaturealmostcompletelyhidesfromusthemultiplicitythatHeisenbergseestoilingbehindthescenes.Eventhebest-designedexperimentsrevealtheobjectivecoexistenceofalternativepossibilitiesonlyindirectly,becauseeachtrialofanexperimentendsinadefinite,singularresult.Ourmostnearlydirectevidence

1/ThroughoutthischapterImakenoeffortscrupulouslytoattributeideastotheiroriginators;thatwouldrequireahistoricalstudy,somethingforeigntomypurposeshere.Rather,Iattempttomarshalrelevantportionsofthephysicscommunity'squantum-mechanicallorearoundthecentralproblemofthisbook.References,therefore,willservemerelyas

convenientwaysofidentifyingcertainargumentsandasevidencethattheydeserveourattention.Hence,thereadershouldnotinferfromtheabsenceofanattributionthatanideaoriginateswithme(onemaybeconfidentthatitdoesnot)oreventhatitreceivesitsclearestexpositionhere.Inadditiontothesourcescitedinthetext,however,Imustmentiontwoveryhelpfulworks:AbnerShimony'sarticle,"RoleoftheObserverinQuantumTheory,"intheAmericanJournalofPhysics31(1963):75573;andBernardd'Espagnat'sbook,ConceptualFoundationsofQuantumMechanism,2ded.(Reading,Mass.:W.A.Benjamin,1976).

comesfromcarefullycontrivedexperimentsinthediffractionofparticles,commonlyelectronsorneutrons,whicharesentthroughanarrowapertureoracrystallatticetobedetectedatasurface.Theretheybringcontrarypossibilitiesintodirectconfrontation,producingthecharacteristicpatternsofinterference.TheseexperimentstipNature'scloselyheldhand,showingasitwerethatNaturehasbeenplayingwithmorethantheregulationnumberofcards.Ishalloutlinethesalientfeaturesoftwodiffractionexperiments.

TheDouble-SlitExperiment

Theconceptuallysimplestversionofthedouble-slitexperimenttranspiresinadeviceresemblingatelevisionvideotube.Atthenarrowendasourceofparticles(an"electrongun")sendsanarrowbeamtowardafluorescentscreenatthelargeend,whereeacharrivingparticlegeneratesaflashoflightasitstrikesoneofthemicroscopiccrystalsthatcoattheinnersurface.(Apermanentrecordofthesearrivalscouldberecordedonaphotographicemulsion,whichalsoconsistsofmanymicroscopiccrystals.)Iftheirjourneywereunimpeded,theelectronswouldproduceafocusedspotoflightatthescreen,buttheycanreachitonlybypassingthroughtwonarrowopeningsinaninterveningmetalplate.Aftersqueezingthrough,theoriginallywellfocusedbeamspreadsout;thenarrowertheopenings,thebroaderthespread.Thiseffect,calleddiffraction,occursateachslit.

Wheneitheroftheslitsisblocked,thearrivingparticles,havingpassedthroughtheotherone,buildupauniformspreadoflightatthescreen.Butwhenbothareopen,sothateachelectronhasa"choice"astoroute,theflashesoflightbuilduparegularpatternofalternatinglightanddarkbandsorspots.Nowthattheopportunitiesaredoubled,theparticlesshunhalfoftheplacesthattheyfreelymovedtowhengivenonlyasinglewaytogetthere.Thisphenomenoniscalled

interference,andthepatternoflightanddarkiscalledaninterferencepattern.Contrarytocommonsenseintuitions,interferenceoccursforindividualparticlesitisnottheresultofinteractionsamongthem.Thisstrangeconclusionfollowsfromthefactthattheexperimentercanreducetheintensityofthebeamtosuchalowlevelthat,asidefromrareexceptions,eachparticlemakesasoloflightbe-

tweenthesourceandthecrystalthatdetectsitsarrival.Thatexpedientkeepstheparticlesfromjostlingoneanotherastheymovetowardthescreen.

Thisisacuriousresult:Ourordinarynotionofanobjectiveworldleadsustoexpectthatanelectronthattravelsfromthesourcetothedetectormustpasseitherthroughoneopeningorthroughtheother.Andwhethertheoneitdidnotmovethroughwasopenornot,itschancesofarrivingatanydetectingcrystalshouldbethesame.Forhowcouldthemereexistenceofanotherpossibleroutealterthemannerofarrivalbythepathactuallyfollowed?Thisresultmakestroublebothfordeterminismandforanindeterminismoftheordinary,prequantalsort.Accordingtoprequantaldeterminism,thepossibilityoftheotherpathexistsonlyintheobserver'smindandmeansnothingtotheelectronitself.Theroadnotchosenneverwasanobjectivepossibilityfromthemomenttheelectronleftthesource;hence,themerepresenceofanuntraveledalternativepathcouldinnowayaffectanelectronpassingalongtheoneactuallytaken.Andordinaryindeterminismpicturesapasteventassettled,definite,andsingle,howeverpregnantwithpotentialitiesitmayhavebeenwhileweawaitedit.Ineitheroftheseviews,eachelectronthathitstheemulsionarrivestherebypassingdefinitelythroughoneslitortheother.Openingupanalternativepathtothedetectorshouldmerelypermitthepassageofmoreelectronswithoutmakinganypossiblepointofarrivallesspopularthanformerly.

TheObstructedDoubleSlit

Particledetectors,suchasfluorescentmicrocrystalsorGeigertubes,wireloops,etcetera,canbeinsertedimmediatelybehindeitherorbothoftheslits.Themicrocrystalstraptheparticles,andtheygonofarther.Aloopletsthechargedparticlepass,butnotwithoutinducingapulseofcurrentbymeansofthemagneticinteraction.Mostofthe

particlessentintotheapparatusbythesourcestopattheplatethatsurroundstheslits,butsomearerecordedbythedetectorsatthetwoslits,inroughlyequalnumbers.Ifadetectorblockseitherorbothslits,nointerferencepatterncanbeproduced,ofcourse;but,evenifthedetectorslettheparticlespass,theyarriveatthefinalplaneinauniformdistribution,withnohintoftheinterferencebandsthatmarkthestandardexperiment.

TheDavisson/GermerExperiment

Longbeforephysicistsachievedtheconceptuallyneatbuttechnicallydifficultfeatofmakingmaterialparticlesdiffractthroughapairofslits,C.J.DavissonandL.H.Germer(1927)hadrecordedtheinterferencepatternmadebyabeamofelectronsthathadscatteredfromacrystallattice.Thestoryofhowtheinterferencepatternoccursinthedouble-slitexperimentappliesinitsessentialfeaturesalsotothisone,soIshallnotdescribeitindetail,excepttonotetwosuggestivepointsofdifference.(1)Insteadofbeingdiffractedbypassingthroughemptyslits,thebeamofelectronsisspreadbythecrystalbecauseofcollisionswithitsatoms.(2)Insteadofofferingonlytwopossiblepathstoeachparticle,thisexperimentoffersbillions,oneforeachofthepossiblecollisionsthatcontributetothefinalpattern.

Since1927thediffractionofmaterialparticlesbycrystallatticeshasbecomeastandardlaboratoryprocedure:Socommonplaceisitthatelectronsandneutronsarebothnowusedasprobestoanalyzethestructureofunknowncrystals.Interferencehasalsobeenobservedinscatteredbeamsofheliumatoms.Thecollisionsinelectrondiffractionoccurbyelectricalrepulsion,andthoseinneutrondiffractionbytheshort-rangeandfarstrongernuclearforce.

Thedouble-slitandtheDavisson/Germerexperimentsposethesamevexatiousproblem:Howcanwespeakcoherentlyaboutthesimultaneousoccurrenceoftwo(ormany)mutuallyexclusiveevents?Ishallproposeasolution,drawingexamplesfromtheconceptuallysimplerdouble-slitexperiment.TheexperimentofDavissonandGermerwillproveusefulbelow,intestingsomeproposedinterpretationsofquantum-mechanicalprobability.

TheLogicofPotentiality

Theimageofaparticlepassingdefinitelyalongoneortheotherofthetwopathsmustcontainaseriousflaw.Wecanscarcelyfindwordstodescribetheseexperiments,muchlessexplainthem.Ishalltreatthedouble-slitexperimentaschallengingustofindawaytoassigntruthvaluestothetwopropositionsAandB:

A:TheparticlepassedthroughslitA.

B:TheparticlepassedthroughslitB.

Becausewereservetheterm"particle"forobjectsthathavejustonelocationatatimeandtakeasinglepathingoingfromonelocationtoanother,thesepropositionscannotbothbetrue.Norcantheybothbefalse,becauseaparticlecannotreachthedetectorwithoutpassingthroughtheslits.PrequantalcommonsensesaysthateitherAorBmustbetrueandtheotherfalse.Butaswehavejustseen,thathypothesisentailstheabsenceofinterference,indirectconflictwiththeexperimentalresult.Hence,allpossiblejointallocationsoftruthvaluesareblocked;wesimplycannotassignthemtothesepropositionsastheystand.

Threepossibleroutesofescapefromthisapparentimpassehavebeensuggested,twoofwhichIshallpassoverwithbutscantmentioninfavorofthethird,Heisenberg'sobjectificationofprobability.First,wemightacceptNielsBohr'sadvicetoavoidformulatingpropositionsabouttheobjectsastheyexistapartfromourselvesandtospeakinsteadonlyabouttheoutcomesofactualexperiments.Ifwefollowedsucharulewhendescribingthedouble-slitexperiment,wewouldnotsaythatanyelectronpassesthroughaslit,forinthisapparatusnoinstrumentdetectsitspassage;thus,wewouldavoidtheperplexingquestionofwhethertoaffirmordenyAandB.Yetanypropositionassigningapositionontheterminalsurfacewouldprovetobeunequivocallytrueinsometrialsoftheexperimentandfalseinothers.Thisabilityunambiguouslytoassigntruthvaluestopropositionswouldhavebeenpurchased,however,bygivinguptherighttothinkofobjectsasiftheyexistobjectivelyinthemselves,apartfromourcontactwiththem.LetussetasideBohr'sproposalasinsufficientlyrealistic.

Ishallalsopassoverattemptstoproduceanempiricallogicspeciallytailoredtoquantumphenomena,becauseitsapplicabilityseemslimitedtoexperimentsinatomicphysics.Itsadvocatesdonotrecommenditforordinarydiscourse,notevenforreasoningaboutthe

quantumtheoryorprovingtheoremswithinit.(See,e.g.,Putnam1968,Gardner1971,Bub1979,andHellman1981.)A"quantumlogician"mustadoptanequivocaluseofthelogicaloperators,alteringtheirfunctionsaccordingtothemeaningofthepropositionstowhichtheyareapplied.Itseemsfairtocomplainthat,althoughquantumlogicprovidesacoherentconceptualorganizationofthephenomena,itdoesnotclearuptheproblemofhowtothinkaboutthemrealistically.

However,byemployingamodallogicofphysicalpossibility,modeledonthestandardoneoflogicalpossibility,weshallfinditpossibletospeakcoherentlyaboutquantumphenomenawithouttheshortcomingsofthetwoproposedsolutionsmentionedabove.Toqualifyasanattractivealternative,thisploymustpasstwotests:Itmustprovideaformalsolutiontotheproblemofdescribingquantumphenomenacoherently;anditmustincreaseourunderstandingofthetheorybysupportinganinterpretationthatreferstoobjectivepropertiesofmaterialthings.InthefollowingparagraphsIpresentsomeexamplestoshowhowamodallogicofpotentialityandactualitypermitsaformallycoherentdescriptionofquantumphenomena.Followingthat,Irecommendaninterpretationintermsofphysicalpossibility.

Letusconstructsomedescriptionsofthedouble-slitexperimentthatusethemodalqualifiers"potentially"and"actually."Thisexpedienttreatspotentialityasanaspectoftheobjectiveworld,liketemporality.Noassertionaboutthetemporalworldcanbeeithertrueorfalseunlessitcarriesatleastimplicitlyatemporalqualifier;similarly,informingamodallogicappropriatetoquantummechanics,weadopttherulethatvalidlyformedassertionsabouttheworldmustcarryoneofthemodalqualifiers,"actually''or"potentially."Onlythenmaytheybeassignedtruthvalues.

Wecanfindtherulesforthismannerofspeakingbyanalogytothestandardmodaltreatmentoflogicalpossibilityandnecessity.Justas"possiblyA"doesnotcontradict"possiblynot-A,"sotheconjunction"potentiallytheelectronpassedthroughslitAandpotentiallyitpassedthroughB"alsoescapesself-contradiction.Further,"notpotentiallyA''meansthesameas"actuallynot-A,"and"notactuallyA"isequivalentto"potentiallyAandpotentiallynot-A,oractuallynot-A."Otheranalogiesalsooccur.

Interpretersofquantummechanicsoftensaythatwecannotmakeaclassicalpictureofwhattheatomicparticlesaredoing.Heisenberg'streatmentofpotentialityinthedouble-slitexperimentillustratesthetruthofthisadageifproperlyunderstood.Itdoesnotmeanthatwemustrefrainaltogetherfromdrawingpicturesintheclassicalstyle;rather,wemustflytotheoppositeextremeanddrawasmanyaspossible.TheresultisanythingbutNewtonian.Intheplaceformerlyoccupiedbyasinglepicturewemusthangmany,overlaidoneonanotherwithintheframeofpo-

tentiality.Forexample,theelectronbeamspreadsasitemergesfromaslitnotbecausesomeparticlesgoonewayandsomeanotherorbecausenonegoesanywherebutbecauseeachindividualtakesonthewholerangeofpositionsatthefluorescentscreen.Indeed,anelectronreacheseachcrystalthereintwoways,arrivingfromslitAandfromslitB.Howcanasingleparticleoccupymorethanoneposition,andhowcanitreacheachofthembymorethanoneroute?Itperformsthesefeatsnot"actually"but"potentially."Letusseehowthesestrangelocutionsflowfromthetheory.

Likeanyofthetheoriesofphysics,quantummechanicsconsistsofaformalcalculusinterpretedaccordingtospecifiedrules.Withasingleexception,thesymbolsonwhichitoperatesrepresentthestandardmechanicalproperties,suchasposition,momentum,andenergy.Butthequantumtheoryalsooperateswithanothersymbol,acomplexnumber2calledtheprobabilityamplitude.Thetheoryspecifiesthestateofasystembyassociatingeachpossiblevalueoftheordinaryphysicalvariableswithavalueofthisnewquantity.Itssquaredmagnitudeisrelatedtoordinaryprobabilitybyrulestobediscussedbelow.

Althoughonlythesquaredmagnitudeofaprobabilityamplitudereceivesadirectinterpretation,thecomplexnumbersthemselvesalsoplayanimportantroleinthetheory.Onoccasion,astraightforwardapplicationwillproducetwoormoreinstancesofastateofaffairs,suchasanelectronhavingreachedafluorescentcrystalbywayofslitAandbywayofB.Bothpossibilitiesarequalifiedaspotential,buttheyarequantifiedwithdistinctcomplexnumbers.Incasesofthissortthetheorymergesthesepa-

2/(Forthebenefitofreadersunfamiliarwithcomplexnumbers.)Theconceptofacomplexnumberisageneralizationoftheconceptofasigned,realnumber.Signednumbersmayberepresentedbythepointson

aline(say,thex-axis),thosetotherightofzerobeingpositiveandthosetotheleftbeingnegative.Complexnumbersmayberepresentedbythepointsinaplane;hence,theyincludeasspecialcasestherealnumbersonthex-axisandthepureimaginaries,definedasthosethatlieonthey-axis.Justastworealsignednumbersthatlieonoppositesidesofthezeropointtendtocancelwhenaddedtogether,sotwocomplexnumberslyinginoppositequadrantsoftheplanetendtocancelwhenadded.Themagnitudeofacomplexnumberisthedistancebetweenitsrepresentativepointandtheorigin,anditsphaseistheanglebetweenthepositivex-axisandthelinejoiningtherepresentativepointtotheorigin.Apairofcomplexnumbersofequalmagnitudeandoppositephase(theanglesdifferby180°)sumuptozero.

rateassertionsofthesamepropositionintoasingleonebearingaprobabilityamplitudethatisthesumofthosebelongingtothecombinedassertions.Becausetheamplitudesmayhaveoppositephases,thesummaybelessthaneitheroftheseparatevaluesandassmallaszero.Onoccasion,therefore,theindividualassertionsofaproposition,allofwhichcontributetothecompletestate-description,maynullifyeachother.Infact,thishappensforcertainpositionsinthedetectingscreenofthedouble-slitexperiment,wheretheeffectiscalledinterference.

Fromthesehintsweseehowamodallogicofquantummechanicscanwork,parallelingthekindofreasoningweperformwithlogicalnecessityandpossibility.Morepressingthanthedetailsoftheformalmodalcalculus,however,isthequestionofinterpretation.Howcanweunderstandpotentialityasanobjectivemodeofbeing?

InterpretingPotentiality

Ishallnottakeupherethedeeperquestionofhowtofitpotentialityintoabroad,realisticviewoftheworld.Thattaskmustawaitthefurtherexpositionofsomeprinciplesofthequantumtheory.Letitsufficeheretodemonstratethataninterpretationparalleltothatoflogicalpossibilitymayalsobeconstructedforquantum-mechanicalpotentiality.Thecentralconcepthereisphysicalpossibility,andthequantumtheory'speculiarbrandofitcarriesusalongpathsnotchartedbythetwocommonsensevarieties.Letusnotethedifferences.

CounterfactualPossibility.

EventhoughNewton'stheorytellsarigidlydeterministicstory,itsapplicabilitytodiverseobjectsgivesittheflexibilitytospinalternativetales.WecanconstructvariationsonthehistoryofasystemofNewtonianparticlesbyimaginingotherpositionsand

velocitiesthanactuallyobtain,orbyimaginingsystemscomposedoffewerormoreparticlesofthesameorothertypes.Withintheconstraintsofanydeterministictheorythatlaysdowngenerallawsbutdoesnotlegislatespecificcircumstances,weconstructphysicallypossibleworldsasalternativestotheactualonebyinsertingintothetheoryconditionscontrarytofact.Thesamemethodservesforconstructingpossibleworldsalsowithinindeterministictheories,in-

cludingquantummechanics.ThepossibilitythatweenvisioninthiswayIshalldenotebytheterm"counterfactualpossibility,"orsimply"C-possibility."Thiskindamountstonothingmorethanimaginabilitywithintherulesofaphysicaltheorybutcontrarytothefactsoftheworldasitis.

RealPossibility.

Alternativeworldsconstructedinthiswayarepossibleonlyinaweaksense,forNewtonianmechanicsallowsnolaxity:Tweakonethreadinthecausalfabricitweaves,andtheentirestructuretrembles.But,conceivably,Newtoniandeterminismdoesnotholdarigidgripontheworld,sothatthereissomefreeplayinnature'smachinery.CharlesSandersPeirce(1892)urgessuchahypothesis,pointingoutthatinescapablelimitsontheprecisionofmeasurementbarusfromeverprovingthatcompletedeterminismisafact.Noexperimentcoulddomorethansetanupperlimitontheslippageallowedamongthepartsofthegreatmachine.Suppose,then,thatahumanbeingoranatomisreallyfree,undertheexternalandinternalconditionsprevailingobjectivelyatacertaintime,bothtoperformandnottoperformacertainaction.Inthatcase,evenanomniscientbeingwouldbeobligedtohedgeitspredictionsaboutfutureevents,justbecausethethingsthemselveshaverealpowersto"choose"amongalternatives.Yetwhenthepredictedtimehaspassed,theomniscientbeingwouldwriteasingle,definitehistory.Ifanagenthastherealabilitytodoanactionatacertaintimeaswellastodosomealternative,then,whenthemomentarrives,itisnecessarilythecasethateithertheactionoritsalternativegetsdone.Theagenthasnochoicebuttochoose.Allofthisisperfectlycommonsensicalandcoincides,Isuppose,withwhateveryonenotcommittedtoNewtonian/Laplaceandeterminismbelieves.Accordingtocommonsenseindeterminismthefutureistosomeextentreallyopen.Theobjectsthemselveshaverealabilities;thereareobjectivelypossiblealternativestothecourseofevents.I

shallcallthiskindofcausallooseness"R-possibility."Thissortofpossibilityapplies,ofcourse,onlytothefuture.Thoughitmaybemultipleandindefinite,thepastisalwayssingularanddefinite.Noagenteveravoidsmakingits"choice''whentheopportunityarrives.

WherecanR-possibleeventsbefound?Acompleteanswerto

thatquestionwouldcarryusunnecessarilyintomootissuesofinterpretation.Apartialanswersufficeshere:AllquantumtheoristsagreethatobservationeventsoccurR-possibly.Interpretationsdiffer,however,astowhatkindofprocessestheseare.Somesaythatanyphysicalsystemthatirreversiblychangesitsstatewhenactedonbyanatomic-sizedobjectperformsanR-possibleobservationevent.Otherssaythatonlymindsperformthem.Theseandotherproposalswilloccupyusinchapter10.

HypotheticalRealism.

Observationevents,beingcausalconsequencesofthemicrophysicalprocessestheyreveal,aredistinctfromthem.Wecannottellacoherentstoryaboutthecourseofparticle-diffractionexperimentsoperationally,talkingexclusivelyabouttheobservationsinsteadoftheparticles.Consider,forexample,thearrivalofaparticleinadetectorjustbehindoneoftheslitsintheobstructedversionofthedouble-slitexperiment.

Attheentryplaneofthedetectoramicroscopicactivitystartsacausalsequencethatterminatesinanobservationevent.ThedetectormaybeaGeigercounter,aphotocell,aphotographicemulsion,ascintillator,andsoon.Thelistofcurrentlyuseddetectorsislengthy,andthelistofallpossibleones,ifnotinfinite,iscertainlyopen-ended.Whatcommonfeaturebindsthesedevicesintoasingleclass?Nousablecriterionofmembershipcanbefoundinthefeaturesoftheapparatusitself.ButthesequencethatleadsuptothelightingofalampinthefrontpanelofaGeigercounterbeginsattheslitwithaparticlehavingapositionthereandasufficientmomentumintheforwarddirection.Thepositionmeasurersareunitedintoaclassbythefactthatthecausalaccountsofhowtheyworkallbeginwiththemeasuredparticle'shavingthatpositionandmomentum.(Ishalladopt"passingthroughtheslit"asaconvenientequivalenttothemorecareful

expression.)Wecannotdefinetheatomicactivityinaslitoperationallyintermsofitseffects,indefinitelyvariousastheyare;but,realisticallyandhypothetically,wecanconceiveofitastheparticle'spassingthroughtheslitintothedetector.

Thisinterpretationimpliesthatwhathappensintheslitsisthesameprocessinallexperimentsofthisfamily,whethertheslitsareblockedbyGeiger/Muellertubes,fluorescentcrystals,photo-

multipliers,or,indeed,whethertheyareleftopen.Consequently,instructivecomparisonscanbedrawnbetweenthestandarddouble-slitexperimentandtheblockedversion.

Inthemodifiedapparatuswithparticledetectorsatthedownstreamsideofeachslit,wefindthatsomeparticlespossesstheabilitytocauseobservationeventsthatrevealtheirpresenceinslitA,andaroughlyequalnumberturnupatslitB.Aswelookbackonthecompletedexperimentweknowthat,foreachparticle,eitheritcausedtheA-observationoritcausedanalternative,suchastheB-observation.Aretheseresultsproducedbyexercisingrealpossibilities?Tofindevidenceforindeterminacywemustcomparethetwoversions.Thecomparisonrevealsmorethanjusttheindeterminismoftheexperimentalresults;italsopointsoutthelimitsoftheconceptofR-possibilityandtheneedforanew,peculiarlyquantalconceptofindeterminacy.

WeexplaintheinterferencepatterninthestandardexperimentbymentioningboththepassingthroughslitAandthepassingthroughBaswerecountthehistoryofeachindividualparticle.TheactivityatslitAthatinthemodifiedapparatusgroundsthepossibilityofanA-observationandtheactivityatBthatgroundsthepossibilityofaB-observationarebothgoingoninthestandardinterferenceapparatus.Ofcourse,theobservationofaparticle'spassagethroughAisincompatiblewiththerevelationofitspassagethroughB(atthesametime).Thisincompatibilityholdsjustassurelyforexperiencesofatomicparticlesasitdoesforthoseofcommonsensethingsassurelyasseeingabaseballflyingthroughonewindowneveroccurswiththevisionofthesameballbreakingthroughaneighboringone.Nevertheless,fromtheinterferenceexperimentwelearnthattheatomicactivitiesthatgroundatleastsomeincompatibleobservationsarenotthemselvesincompatible.(Canthesamebesaidoftheatomicgoings-onthatunderliethebaseballexperiences?Ishallreturntothat

questioninchapter10.)

Twoconclusionsfollowimmediatelyfromthecomparisonofthetwoexperiments.First,intheapparatuswithdetectorsattheslitseachparticlethatcausedapassing-through-A-observationalsowasdoingatslitBwhatmighthavecausedapassing-through-B-observationinstead.Therefore,theAandBobservationswereachievedbytheexerciseofanR-possibility;theobservationaloutcomeofthemodifiedapparatusisobjectivelynot

determined.Second,becausetheactivitiesatbothslitscontributetotheinterferencepatterninthestandardapparatus,wemustrecognizeanunprecedentedkindofmultiplicity,onethatinvolvesrealalternativesforthecourseofeventsbutinwhichthe"choice"amongthemneednotbemade.Rpowersalonecannotaccommodatethemicrophysicaleventsthatproducetheinterferencephenomenon.Theactivityintheregionoftheslits,revealedintheblockedversionbyeithertheA-observationortheB-observation,goesonsimultaneouslyinbothslits,notalternatively.Theparticledoesnot"choose"betweenthoseactivitiesastheinterferenceexperimentprogresses.Becausetheybothhelptogeneratethefuturestate,theyhaveboth"happened''(inapeculiarsense),asamatterofobjectivehistory.Hence,theydonotoccurasmanifestationsofR-possibilities.InadditiontoCandRpossibilities,wemustrecognizeamultiplicityintheactivitiesoftheparticlesthemselves,onethatdoesnotbecomesingleastheindefinitefutureslidesintohistory.Ishallcallit''quantalpossibility,"orsimply"Qpossibility."Considertwoexamplesoftheusefulnessofthisconcept.

QuantalPossibility.

AversionoftheDavisson/Germerexperimentcanbedonewithneutronsdiffractingfromacrystal.Toexplaintheresultinginterferencepattern,wetellhoweachindividualneutroninteractsbymeansoftheshort-rangenuclearinteractionwitheverynucleusofthecrystal.Eachparticlethatcontributestotheinterferencepatternhasbeendeflectedfromitsoriginalcoursebyacollisionwithnucleusnumber1,anencounterwithnucleusnumber2,andsoon.TheseinteractionswiththenucleiofthecrystallatticecannotbeunderstoodmerelyasR-abilitiestogenerateobservationrecordsoftheparticle'spresenceatthosemicroscopiclocations.Nomeasuringinstrumentcouldlocateaneutronsoprecisely.Norisitthecasethat,whentheexperimentiscomplete,onepossibledeflectionbyanucleushas

definitelyhappened,andtheothersdefinitelynot.ThesecollisionsarenotR-possibleactivities.Yeteventsofsomekindtheycertainlyare,becauseindividuallytheycauseaneutrontodeflectfromitsoriginalcourse,andcollectivelytheydeterminethateachneutronavoidscertainregionsofthepattern.

Inthesecondexample,thestandardquantum-mechanicalpictureofthemotionofatomsandmoleculesassignscharacteristic

shapestotheelectrons'orbitals,thefunctionsthatdescribetheparticles'potentialpositionsrelativetothenuclei.Thesefunctionshaveregionsofgreaterandlesserprobabilityamplitudeaswellaspeculiarlyshapednodalsurfaceswheretheamplitudedropstozero.ThesepotentialpositionscannotbeunderstoodascausesofR-possiblepositionmeasurements,againbecausenoinstrumentcouldlocateaparticlethatprecisely.Yetobservationsrelatedtosuchmattersasthestabilitiesofatomsandmoleculesandtheirproclivitiesforlinkingthemselvesintolargerstructuresaregovernedbythedetailsofthesepotentialpositions.Noneofthepositionsbecomestheexclusiveoneatanymomentashistorysweepson;themoleculewouldnotbestableifonedid.They,too,arenotR-possibilities;yettheyformapartofreality.Wemustconceiveofthemintermsofanotherkindofmultiplicity,namely,ofoptionsthatneednotbepickedup.TheyareQ-possibilities.

Asingle,simplystatableQ-possibilitycanotbedefinedintermsofasingleR-possibleevent,orevenintermsofafinitesetofalternativeR-possibilities,nomatterhowlargethesetmaybe.TheQ-possibilitymayindeedbeassociatedwithanopen-ended,andthereforeessentiallyundefined,"set"ofR-possibleevents.ButsuchanassociatiodoesnotqualifyasareductionoftheconceptofQ-possibilitybecausethemembersofthisopen-endedsetcannotbepickedoutexceptbyreferencetothesingleQ-possibleevent.Acompleteexplicationofquantum-mechanicalpotentialitymustrelateittothemanifestingofQ-possiblestatesofaffairs.ItmustconnectQ-possibilitiesbothtodirectmeasurementsofthemandtomeasurementsofeventstowhichtheQ-possibilitiesmakeindirectcausalcontributions.Letusconstructaformalinterpretationofpotentiality.

CriterionofPotentiality

IshallfollowtheleadofEinstein,Podolsky,andRosen(EPR),whoproposethefollowing"criterionofreality":

If,withoutinanywaydisturbingasystem,wecanpredictwithcertainty(i.e.,withprobabilityequaltounity)thevalueofaphysicalquantity,thenthereexistsanelementofphysicalrealitycorrespondingtothisphysicalquantity.[1935,p.777]

ThereferencetocertaintyinthiscriterionalignsitwithHeisenberg'sconceptofactuality.Letusextendittoincludepotentiality.

InproposingacriterionofpotentialityIshallusetheterm"system"torefertoasingleparticleoracollectionofthem;andtheterm"variableproperty"torefertoanyofthe"observables"ofquantummechanicsposition,momentum,energy,angularmomentum,andsoon,belongingtoparticlessinglyoringroups.Andby"measuringinstrument''Ishallrefertoathermodynamicallyirreversibledevicethatiscausallyconnectablebothtoanatomicparticleandtoahumanbrain(thatis,observablebyhumansenses)insuchawaythatsomedistinctstatesoftheparticlecangeneratedistinctstatesofthedevice,whichinturncausesdistinctperceptualstatesofthebrain.Finally,theterm''observer"isleftdeliberatelyindefinite,inordernottoanticipatetheargumentsofthenextchapter:Anobserverissomesystemcapableofbeingconnectedtothemeasuredobjectinsuchawaythatdistinctstatesoftheobjectcausecorrespondingstatesintheobserver.Forthepresentletusleaveitanopenquestionwhetheranobserverisaphysicaloramentalentity,animalormineral,simpleorcomplex,whetheritisthemeasuringinstrumentitselforsomethingcausallyconnectedtoit.

IntheEPRcriterion,"predictingwithcertainty"meansdeducingcorrectlyfromknownfactsandwiththeaidofatheorythatameasurementwillyieldasingledefiniteresult.Tovaryingdegrees,measurementsofphysicalquantitiesarealwaysindirect.Measurementisatheory-ladenart:Themeasuredvalueisinferredfromtheresultofthemeasurement,notgiventransparently.Whenweinfertheapproximatepositionofaparticlefromthebehaviorofafluorescentcrystal,themeasurementisonlymodestlyindirect;whenwededucethemomentumoftheparticlesinabeamfromthesizeoftheinterferencepatterntheyproduce,theinferentialchainissomewhatlonger.Whenweexplaintheinterferencepatterninthedouble-slit

apparatusbymentioninganindividualparticle'spassagethroughaslit,wealsoinferaposition,bymeansoftheory,fromtheresultsofmeasurement;inthiscase,however,theinferencepointstomorethanoneofthequantity'spossiblevalues.Inthesamespirit,weinfertheshapedcontinuumofpositionsofthehydrogenatom'selectronfrommanysortsofmeasurements,includingspectroscopicdataandfactsaboutchemicalreactions.Bymeansof

quantummechanicsweinfer(correctly,asfaraswecantell)notasingledefiniteresultforthevalueofatypicalphysicalquantitybutmanyvaluesnotbecausethetheoryhesitatesorhedgesitsbetsbutbecauseallthesevaluesare"elementsofphysicalreality."

Letuspulltheseconsiderationstogetherintothefollowingformalcriterion:Avariablepropertyofasystemhasoneofitspossiblevaluespotentiallyatacertaintimeifwecanpredictcorrectlythesubsequentobservedbehaviorofthesystemontheassumptionthatthepropertyhasthatvalue.Thevalueobtainsonlypotentially,thatis,notactually,ifatleastoneothervaluealsocontributestothetheoreticallypredictedbehavior.Avariablepropertyhasoneofitspossiblevaluesactuallyatacertaintimeifthatvalueandnoothercontributestothetheoreticalexplanationofthesystem'ssubsequentbehavior.

Twofeaturesofthiscriterionofpotentialityandactualityneedemphasis."Subsequentbehavior"includesbutisnotlimitedtodirectmeasurementsoftheproperty;italsoincludesmeasurementsofotherpropertiesthatarecausallylinkedtothepropertyinquestion.Note,also,thataccordingtothiscriterionactualityismerelyarestrictedformofpotentiality.Bothareelementsofphysicalreality.Ishallhavesomethingmorepositivetosayaboutactualitybelow.Butfirstletusdrawoutsomeofthemeaningofthisversionofthecriterion.

ApplicationsoftheCriterion

Trajectories.

Wouldanyexplanatoryinsightbegainedifwethoughtofaparticleastravelingsimultaneouslyalongseveralpotentialpaths?Atypicalparticlehasateachinstantseveralpotentialpositions.Becauseallofthemcontributetothestorythatexplainsthemeasurablepropertiesofthesystem,theyallparticipateinphysicalreality,andwearefreeto

associatetheminanywaywewish.Wecould,forexample,collectatemporalprogressionofpositionsinsuchawayastomimicastandardNewtoniantrajectory.Typically,manysuchcollectionsarepossible.Butagroupingofpotentialpositionswouldbemerelyanarbitraryimpositionunlesseitherexperimentortheoryjustifiedassigningtoitacommonprobabilityamplitude.Experimentdoesnot,becausethesystemisincapableofmanifestingsuchacollectionasaunitinasequenceofpositionmeasurements.Thefirst

interactionoftheparticlewithadetectorwouldintroducenewprobabilityamplitudesforthepositionsthatliefartherdownstream.Atmost,oneofthepotentialpositionscanberevealedwiththeprobabilityamplitudethatthefreelymovingparticlehas.Nordoestheoreticalanalysisnaturallygroupcoordinatedpositionstogetherinsuchawayastopermittheextractionofacommonprobabilityamplitudefromacoordinatedsetofpositionsandtimes.Thereasonforthisdifficultyliesinthetechnicalfactthatthephasevelocityofthequantumwavediffersfromthevelocityoftheparticle(whichequalsthegroupvelocityofthewave).Iftheassociationissimplyimposedonwhatthetheorydelivers,insteadofbeingsuggestedbysomehintfromthedynamicsitself,amereconjunctionofpotentialpositionsrepresentsatrajectoryratherweakly.Iconcludethatthecriteriondoesnotsupportaninterestingconceptofpotentialtrajectories.

PastIndefinite.

Canwediscovertheactualexistenceofatrajectoryafterthefact?Suppose,forexample,thatacertaindetectorregisterstheparticleinanarrivaleventthatbelongstoaparticulartrajectory.Mayweconcludefromthisfactthattheparticlehasactuallytraveledstraightfromsourcetodetectorandnotevenpotentiallymovedalonganyotherline?Accordingtothequantumtheorysuchaconclusionwouldbefalse:Itwouldamounttoasserting,amongotherthings,thatifinthistrialadetectorhad(C-possibly)beenplacedjustatthenozzleofthesource,itcouldnotQ-possiblyhaveregisteredtheparticle'semergingthereatanytimebuttheonebelongingtothistrajectory.TheconclusionisfalsebecauseemergingsatothertimesremainedasQ-possibilitiesuntiltheiropportunitieshadpassed.Replicationsoftheexperiment,inotherwords,sometimesyieldoneoftheseresultsandsometimestheother.Allofthepotentialitiespossessedbyasystemcontributetoitsobjectivestateuntilsomeofthemarecanceledasthe

wavefunctioncollapsesduringameasurement.Actualizationdoesnotoperateretroactively.Wecannotdrawevensoapparentlyinnocentaconclusionasthattheparticlehadanactualpositionrightinfrontofthedetectorjustbeforethemomentofregistration.

Anobject'spossessingacertainpotentialvalueofapropertyamountstothis:Theobjecthasapropensitytomanifestthatvaluethroughitseffects,eitherrelativelydirectlyinameasure-

mentofthepropertyitselforrelativelyindirectlyinameasurementonanotherpropertycausallydependentonthefirst.Thecriteriondoesnotspecifywhatitisfortheobjectinitselftopossessapotentialvalueofanyproperty,becauseitsaysnothingaboutthetendencyexceptinrelationtoitseffectsinotherthings.Fromtheviewpointofrealism,then,thiscriterionisdesirableyetcuriouslyunsatisfying.Inexplicatingpotentialityasakindofpropensityweimply,indeed,thatitisanintrinsicproperty,lurkingintheobjectevenwhenwedonotletitrevealitself;but,becauseweseeonlyitseffects,thepropensityitselfstayshidden.Ishallreturntothisperhapsdistastefulobscuritybelow,arguingthatitisaninescapablefeatureofourepistemologicalsituationvis-à-vistheworldofobjects.

Theindefinitenessrevealedbythequantumtheorygoesfarbeyondmereindeterminism.Notonlyisthefuturetosomeextentopen,buteventhepastrefusestobepinneddown.Thehistoryoftheworldcontainsalternativepotentialstrands,allobjectivelythere.Incommonsenseusage,potentialitypointsonlytowardthefuture,towhatmayyetcometopass,andmultiplepossibilitiesareeitherrealizedorrejectedwhentheirtimecomes;butinthequantum-mechanicalsensepotentialityremainsmultipleforalltime.Thepastisjustasindefiniteasthefuture;realityitselfismultiple.Thismultiplicityofpresentandpaststronglyoffendsourcommonsense.Anobjectivelyindefinitefuturemightbeacceptable,buthowcanwecometotermswithanobjectivelyindefinitepast?

Onemitigatingconsiderationshouldbenoted,however.Oneisstronglytemptedtospeakofquantum-mechanicalindefinitenessinnegativeterms,asiftheworldpicturedbythetheoryissomehowlesssubstantialthantheworldofNewton,lackingsomethingthatNewton'spossesses.Butthatmannerofspeakingundervaluesquantumtheory.Theworldofquantummechanicsisnotlessrobustthantheclassical;farfromwantingcolor,life,oractivity,itteems

withasuperabundance.Itissometimessaidthatanelectron"lacksadefinitevalueofenergy,"asiftheparticlewerelessrealthanwethoughtitwasinprequantaldays.Butinfacttheelectronisricherinitspropertiesthanclassicalphysicsallowsfor;ithastheabilitytorevealmanydifferentvaluesofenergywhenputtothequestionbyameasurement.Thequantal

pictureoftheworldisnotpaleandshadowy,likeaMonetcathedralinmist,butbewilderinglyelaborate,likeaBrueghelcrowdscene.

Schroedinger'sCat.

Whenpreciselydoesthetransitiontoactualityoccur,andwhatsortofcausalinteractionisresponsibleforit?ThesequestionsareforceduponusbyathoughtexperimentinventedbyErwinSchroedinger(1935,p.812)andnowpartofthestandardloreofquantummechanics.InSchroedinger'sstory,acatisconfinedtoanopaquebox,whichalsocontainsalethaldevicethateitherkillsthecatorremainsinominousquiescence,dependingonanatomiceventthathastwopotentialoutcomes.Potentially,therefore,thedevicedoesitsfelldeed,andpotentiallyitdoesnot.Andthecat,whichforthepurposeofthisstoryisconsideredtobeameremachine,lackingaconsciousnessofitsown,waitsinastateofpotentialhealthandpotentialmorbidityuntiltheobserver,raisingthelidofthecontainerandpeeringin,liftsoneofthosetwopossibilitiesintotherealmoftheactual.InhislaterviewsSchroedinger(1956)departedfromtheimplicitdualismofthisparable,choosinginsteadaversionofidealismwithasingle,universalconsciousness.Nevertheless,IshallrefertohisearlierconjecturethatactualizationshappenintheworldofmatterandthattheybeginattheportalconnectingmattertomindasSchroedinger'sconjecture,orSchroedinger'smodeloftheprocessofactualization.Heisenbergrejectsthispicture.Heinsists,instead,that"thetransitionfromthe'possible'tothe'actual'takesplaceduring...thephysical,notthepsychicalactofobservation,"thatis,assoonastheatomicobjectencountersthemeasuringdevice(1958,p.54).Ineffect,Heisenbergadoptstheadditionalpostulatethatmacroscopicobjects,ofwhichmeasuringinstrumentsaretheoutstandingexample,donotsharetheindeterminacyofatomicparticles;themodalityofpotentialityappliesonlytothemicroscopicobjectsofourstudy,nottothemacroscopicinstrumentsbymeansofwhichwestudythem.

Supposethatanobserverexaminestherecordingdeviceinthedouble-slitapparatuslongaftertheexperimenthasended,findingthatitrecordsthepreviousarrivalofapulsefromoneofanarrayofdetectors.InHeisenberg'sview,theobserverthenfinds

outthatthedetectorhaschangedattheearliertimefromastateofactuallybeingquiescenttoastateofactuallyregisteringthearrivalofaparticle.Thediscoveryisatransitionmerelyintheobserver'sstateofmind,butthediscoveredeventisapriortransitionundergonebytheparticleitselffrompotentiallyhavingmanyQ-possiblepositionstoactuallyhavingjustone.Andalltheotherdetectors,theobserveralsodiscovers,havebeenactuallynotactivatedallthetime.Eachpotentialhistorybutonehasnowbeencontradicted(notjustinourknowledgebutalsoobjectively)atthepointwhereitsassertionofmultiplicityranafouloftheuncompromisingsinglenessofameasuringdevice.Theplotthinsduringthecourseoftheexperiment,asthepredictionsofthevariouspotentialhistoriescamedue,oneafteranother.Inthisparadigmaticsituation,transitionsfrompotentialitytoactualityoccurcontinuallyuntil,withafinalrushatthemomentoftheactualization,allthesurvivingpotentialhistoriesbutoneorafewparticipateinageneralcollapse.OrsosaysHeisenberg.InSchroedinger'smodel,allpotentialstates,evenofthemacroscopicinstruments,remaininforceuntiltheexperimentregistersinconsciousness.Onlythendoesthetransitionoccur,everywhereandallatonce.

InHeisenberg'sviewtheobserver'sreadingoftherecordingdevicerevealspreexistingstatesofactuality.Ifourexperienceshowsaparticledetectortohavereceivedtheparticleatacertaintime,thenalltheotherdetectorshavebeeninstatesofactualnonactivationthroughout,fromthebeginningoftheexperiment.Schroedinger'sconjecture,ontheotherhand,retainspotentialpositionseverywhereuntilthemomentthattheexperimentalresultregistersinconsciousness.Uptothatverymomenttheparticlemight,withadefiniteprobability,haverevealeditspresenceelsewhere.

AtthispointinmyexpositionofthegeneralfeaturesofthequantumtheoryImerelynotetheseopposingconjecturesaboutthetransition

frompotentialitytoactuality.Later,whenIturntothetaskofassessingantireductionistargumentsbasedonquantummechanics,itwillbenecessaryformetotakeastandontheissue;thenIshallargueforSchroedinger'sinterpretation.Beforeturningtothoseantireductionisticarguments,however,Imustcompletethissurveyofthequantumtheory.ThusfarIhaveillustrateditsnaturewithparadigmsthatinvolveasingleparticlein-

teractingwithameasuringapparatus.Inordertoshowthefullforceofthetheory'sinsulttocommonsense,Imustnowturntotwoadditionalstockexamplesofquantumsystems,bothofwhichinvolvepairsofparticles.Thefirstoftheseservestolaytorestanattractivemisinterpretationoftheso-calledwave-particleduality.Thesecondintroducestheperplexingproblemofnon-locality.

Duality.

Ifweconcentrateonsingleparticles,wemaybeinclinedtothinkthatthewavethatoccupiesonepoleofthewave-particledualityvibratesinreal,thatis,physical,spacethesamespaceinwhichtheparticleanditsobservermove.Butthatisnotso.Considerthequantum-mechanicalanalysisofaparticleconfinedtoacubicalbox.Thewaveforsuchaparticleisacomplex-numberfunctionofpositionbetweenthewallsofthebox.Thefunctionitselfreceivesnodirectphysicalinterpretationinthestandardtheory.Itssquaredabsolutevalue,however,isareal-numberfunctionofpositionanddoesreceiveaninterpretationasrepresentingprobability.Becausethesquaredwavecanbesuperimposedonthewanderingsoftheparticle,itiseasytosupposethatthewaveandtheparticlecoexist,orexistalternately,orinsomeotherwaysharethephysicalspaceclaimedbytheparticle.Butthatwouldbeamistake,aswecanseewhenweturntoasystemconsistingoftwoparticlesconfinedtoasinglebox.Thewavefunctionforsuchasystemsimplywillnotbesettledintotheparticles'territory.Thepeaksandvalleysofthewavespreadoutoverasix-dimensional"space."Eachpointinthefieldoverwhichthewaveundulatesrepresentsasimultaneouspairofpositionsofthetwoparticles;thex1component,forexample,specifiesthepositionofthefirstparticlealongthex-axisofthebox,andthex2componentdoesthesameforthesecond.Thedomainofthefunctionrepresentsthesetofallpossibleconfigurationsofthetwo-particlesystem,notthesetofspatialpointsinthebox.Thecrestsandtroughsofaquantum-

mechanicalwaveoccupya"space"nevertraveledbytheparticles.ThewavecannotplayMr.Hydetotheparticles'Dr.Jekyll,thoughthatiswhatthenotionofwave-particledualityseemstosuggest.

Infact,the"space"thatformsthedomainofthewavefunctionisaspaceofpossibilities.Eachpossibleconfigurationofthesystemhasitsrepresentativeinoneofthepointsofthispossibility-

space.Regardingtheboxasamicrocosm,wemayseeinoneglancethemultitudeofallphysicallypossibleconfigurationsofthissmallworld.Thesquaredabsolutevalueofthewavefunction,bytakingavalueateachpointinthisspace,assignsaprobabilitytoeachpossibleconfigurationoftheworld.

TheEPR"Paradox."

Multiplicitymaybethefeatureofquantummechanicsmostrepellenttocommonsense,butnonlocalityrunsaclosesecondforthatdistinction.BothofthesefeaturesaresetforthinalltheirstrangenessbyathoughtexperimentdevisedbyAlbertEinstein,BorisPodolsky,andNathanRosen(1935),commonlyknownastheEPRparadox.Thethoughtexperiment,onlyapparentlyparadoxical,hasbeenrealizedinseverallaboratories(ClauserandShimony1978;Aspect,Grangier,andRoger1982;Aspect,Dalibard,andRoger1982).Theexperimentexploitsthefactthatacompositesystemmayhaveasingle,definitevalueforsomeadditiveandconservedpropertysuchasangularmomentumorenergy,eventhoughtheparticlesthatcomposeitequivocate.Typically,twoparticlesinitiallycloselyassociatedinasinglesystemandpossessingatotalvalueofzeroforsomeadditive,conservedpropertysubsequentlyflyapart.Becausethecommonpropertyisaconservedquantity,thesummustretainitsinitialvalueofzero.Therefore,eachparticlemusthavethenegativeoftheother'svalue.Forthesakeofillustration,letussupposethatthepropertyinquestionisacomponentofangularmomentumalongsomedirection.Eachparticlepossessestwopotentialvaluesoftheproperty,sothatmeasurementscanrevealeitherthepositiveorthenegativevalueforparticlenumber1andeitherpositiveornegativeforparticlenumber2.Yettherearenotfourpossibleoutcomesforajointdetermination,butonlytwo:Inonescenariothefirstparticlehasthepositivevalueandthesecondthenegative,andintheothertheassignmentsarereversed.ItisnotQ-possibleforbothtohavethesamevalue;thatis

whythetotalturnsouttobezeroinallC-possibleworldsinwhichitismeasured.InstillotherC-possiblecircumstanceswemeasurethetotalangularmomentumalongotherdirections.Classicalcommonsensetellsusthatthespinofoneparticlecanbeorienteddefinitelyalongjustonedirectioninspace.Butquantummechanicssaysthattheparticlepossessesthesamepotentialvaluesalongeveryimaginabledirec-

tion.C-possiblemeasurementscanrevealsomevaluealongacertainaxis,R-possiblythepositiveandR-possiblythenegative;likewisealongstillanotheraxis,andsoon.

Acceptingthispronouncementofthetheoryforthesakeofargument,Einstein,Podolsky,andRosenbringthefollowingobjection:Supposethat,whiletheparticlesarestillinflighttowardtheirrespectivemeasuringinstruments,wedecidetomeasuretheycomponentofnumber1'sspin,getting,ofcourse,adefiniteresult,positiveornegative.Whicheverresultturnsup,wewillthenknowwithcertaintythatnumber2,whichwewillnotyethavetouchedorotherwiseinfluencedinanyway,hastheoppositevalue,justasdefinitely.Therefore,becausewewillnotyethaveinterferedwiththesecondparticle,itwillalreadyhavepossesseditsvalueevenbeforethecontemplatedmeasurement;therefore,itmustpossessitrightnowasweplanthenextphaseoftheexperiment.Itmustpossessthatasyetunrevealedvaluealready,eventhoughwemaychangeourmindanddecidetomeasurethefirstparticle'sspinalonganotheraxisinstead.Ifweshoulddoso,weknow,theothermeasurementwouldrevealsomedefinitevaluealongthatdirection,andoncethisresulthasbeenrecordedforthefirstparticlewewillknowdefinitelythatthesecond,stilluntouched,possessestheoppositevalue.Then,byanotherapplicationoftheargumentweconcludethattheparticlealreadypossessessomedefinitevaluealongthisotheraxis,aswell.Andlikewiseforeveryimaginablespatialdirection:Becausewecouldplaceourselvesinapositiontoknowdefinitelyaboutthesecondparticle'scomponentalonganydirectionwhatever,allwithoutexertinganyphysicalinfluenceuponit,itmustalready,inandbyitself,possessalloftheinformationnecessarytodeterminetheresultsofanymeasurementwemightC-possiblyinflictuponit.Howcanthisbe?Becausethetheoryperformsaltogethertoowelltosustainanaccusationofincoherence,onemightconcludethatitismerely

incompleteastothestoryittellsofwhattheparticleisdoing.Perhapsadeeperstructureof"hiddenvariables"underliesthepropertyweknowasangularmomentum,andtheotherfamiliarpropertiesaswell,insuchawayastodetermineforeachparticlewhatshallbetheoutcomeofanyC-possiblemeasurement.

Thishypothesisofhiddenvariablesdoesnotcommandalargefollowingnowadays,forvariousreasons.Inthefirstplace,in

ordertoaccountfortheperfectcorrelationbetweenmeasurementsmadeonwidelyseparatedparticles,wewouldhavetosupposethateachcarrieswithitacompletescripttodeterminewhatvaluesitwillrevealwhenitmeetsanidealmeasuringinstrument.Andthatplacesafartooheavyburdenontheinformation-carryingcapacitiesoftheinfrastructureofthesupposedlyunitaryparticle.Second,accordingtoatheoremofJohnS.Bell(1965),nohidden-variabletheorythatprecludesinstantaneouscommunicationbetweentheparticlescouldaccountquantitativelyforallofthecorrelationspredictedbythequantumtheory.Thisdisagreementbetweenquantummechanicsandtheclassof"local"hidden-variabletheoriessetsupanoppportunityforanexperimentalconfrontation.Experimentsofthistypehavebeencarriedoutinseverallaboratories,withresultsthatalmostconclusivelyvindicatethequantumtheoryoveritsrivals.(SeethereviewinClauserandShimony1978,andthemorerecentworkofAspect,Grangier,andRoger1982;Aspect,Dalibard,andRoger1982).

ThekeyassumptionintheEPRargumentisthatproperlyconductedmeasurementsalwaysdonothingbutrevealastateofpriordefiniteness.Therefore,whenadefinitevaluecomestolightinameasurementweareentitledtoconcludethat,momentsbefore,theobjectwasalreadydisposedtoregisterthatresultandnoother.ButforthiscentralpremiseEinstein,Podolsky,andRosenoffernojustificationatall.Nor,obviously,dotheyfeeltheneedofany:Accordingtoclassicalcommonsensethatisexactlywhatameasurementshoulddo.Butjustthisclassicaltruismisdeniedbyquantummechanics.Inthetransitiontoactualityoneofasetofcoexistentpriorpotentialitiesshouldersalltherestaside.Thevalueisdefiniteenoughafterthemeasurementhasbeenrecorded,butearlierthanthatmattersstoodquitedifferently.AlltheQ-possibilitieswereineffectthen.Sotherewillbenoneedtospeculateaboutanelaborate

levelofhiddenvariablesifwearewillingtorelinquishthecommonsenseandnearlysacredpostulatesofdefinitenessanddeterminism.

Butthereismore.Ifwegrantthateachparticlepossessesmultiplepotentialitiesbeforethemeasurement,carryingthemaroundwithit,asitwere,andgrantthatthesheddingofsomeoftheminthetransitiontoactualityisanobjectiveevent,howarewetounderstandtheperfectcorrelationbetweentheshedding

thatgoesonintwowidelyseparated,noncommunicatingparticles?Hereontherightthefirstparticleapproachesameasuringinstrumentorientedalongthey-axis.Thereontheleft,possiblylightyearsaway,thesecondparticlenearsitsdetector,alsoorientedalongthey-axis.Thesecondmeasurementmayhappensolittlelaterthanthefirstthatnomaterialinfluencetravelingatlightspeedorlesscouldconnectthetwoevents.Hence,theyaretrulycausallyindependent.Now,thefirstparticlepossessestwopotentialitieswithrespecttohowitbehavesinitsmeasuringapparatus:Onentering,itmightQ-possiblybendinadirectionthatindicatesapositivespincomponent,andequallyobjectivelyitmightswerveintheoppositedirection,indicatingthenegativevalue.Accordingtoquantummechanicsbothpossibilitiesarereallythere,andtheeventualoutcome,theactualregistrationofjustone,isnotdeterminedbyanythingwhatever.Yonder,lightyearsaway,thesecondparticlefacesasimilardecision.Itmightrevealthepositivevalue,anditmightreallymightrevealthenegative.Theconservationlawwouldbecontravenedunlessthetwovaluesarecoordinatedproperly,buthowisthiscorrelationtobeachieved?Intheabsenceofphysicalcommunication,howdoeseach''know''whichpotentialitiestoerasesoastomaintainthecorrelation?Ishallreturntothispuzzlingquestioninchapter10.

TenMentalEventsinanIndefiniteWorldInchapter8Iarguedthatthereductionprogramofatomisticmaterialismrunsafoulofwhateveryoneknowstobetrueofhisorherownsubjectivementalepisodes.IadvocatedaCartesiandualismofmindandmattertoresolvethediscrepancy,claimingthatonlyamindnotcomposedofparticlescouldbeperformingtheactivitiesweknowassensoryepisodes.InthischapterandthefollowingIreachthesamepositionbyanindependentroute.Iarguethatastraightforwardacceptanceofmaterialismleadstoagapinthecausalstory,revealinganactivityforwhichnomaterialagentwilltakeresponsibility.Again,along-debatedconjectureprovidesthesolution:Onlyanonmaterialmindcouldtriggerthecollapseofthequantum-mechanicalwavefunction.

Intheargumentsofthesechapters,Iassumethatourexperiencesputusintouchwithanobjectiveandatleastpartlynon-mentalworldandthatthepresentstateoffundamentalphysicsprovidesourmostreliableknowledgeastothenatureofmatter.Fromparticletheory,abranchofphysicsinconstantfluxthese

days,wegetafluidlistofthefundamentalparticlesandoftheirmodesofinteraction.Fromquantummechanicswegetaconceptualschemeforunderstandingchangeingeneralbothmotionandtransmutationandhowparticlescaninteracttoformdurablestructures.

Quantummechanics,thoughafundamentaltheory,maybefundamentallywrong.Overarchingmechanicalprincipleshavebeenoverthrownbefore.Forthatreason,anyphilosophicalflourwemightgrindfromthetheorymayhaveonlyalimitedshelflife.Wehave,however,onlytwooptions:waitingforacompletelytrustworthytheorytocomealong(i.e.,forever)ortryingtointerpretwhatwehave,oddandfalliblethoughitbe.Thequantumtheoryhassurvivedabatteryofincreasinglysophisticatedattemptstorefuteitscentralandmostcounterintuitiveprecepts.Ithasearnedtherighttobetakenseriously.Still,ifaradicallydifferentviewofmattereventuallysupplantsthequantumtheory,thenthetaskofinterpretationmustbeginafresh.Itcannotbehelped.Onlyalimitedamountcanbeestablishedfromfirstprinciples.Ichoosetotaketheriskoftentativelytrustingthequantumtheoryinordertosaysomethinginterestingandpossiblynotfalseabouttheworld,ratherthansilentlytowaitforfinaltruth.Quantumtheoryofferssucharichlodeofphilosophicalorethatitwouldbeapitynottomineit.

Therefore,inthesechaptersIsimplyassumethetruthofquantummechanicsasoutlinedinchapter9andsearchthetheoryforsourcesoflightonhowpartsarerelatedtowholes.Theargumentsthatcanbebuiltuponquantum-mechanicalprinciplesdivideintotwogroups.Somefindinthetheory'snoveltreatmentoftheinteractionofparticlesanewsortofcompositionalholism.Othersfindinthetheory'speculiarbrandofindeterminismespeciallyasitcomesintoplayintheprocessofmeasurementhintsofanewsortofunitarycausalactionbyanonmaterialmind.

HolisticFeaturesoftheTheory

Twocloselyrelatedfeaturesofthequantumtheoryrequireustotreatconglomeratesofparticlesinwaysnotrequiredbyearliertheories.Thesefeaturesmaybecallednonadditivityandnonseparability.Letusexaminetheseexamplestoseewhethertheycansupportanew,quantum-mechanicalholism.

Nonadditivity.

Thisfeaturemaybeillustratedbyahostofexamples,includingtheEPRexperimentdiscussedinchapter9.Thesamepointcanbemademoresimply,however,byconsideringtheangularmomentaofthetwoelectronsinaheliumatom.AngularmomentuminNewtonianphysicsisanadditivequantity;thatis,thevalueoftheangularmomentumofacollectionofpartsisgivenbythesumofthevaluesbelongingindividuallytothemembers.Initsownway,quantummechanicsalsotreatstheangularmomentumofacompositesystemasasum,becausetheoperatorthatrepresentstheangularmomentumofthegroupiswrittenasthesumoftheoperatorsfortheindividualparts.However,thequantumtheorygivesastrangenewtwisttothephenomenon:Itshowsthatthewholesystemmayhaveadefinitevalueofthepropertywhilebothpartsremainindefinite.Aheliumatommayhaveatotalangularmomentumequaltozero,andhavethatvalueexactly,eventhoughthetwoelectronswhosemotionsgeneratetheangularmomentumhaveindefinitevaluesofthisproperty.

Insuchastate,andstateslikethisareplentiful,thewholesystemismoredefiniteonemightsayitismoreactualthaneitherofitsparts.Onemightevenwanttoaddthatthewholeismorerealthanitsparts,hencethatitsexistenceisnotmerelytheoutcomeoftheirindividualactions.Butthecaseforsuchastatementisnotastrongone,becausequantummechanicspermitsustoformulate,inapeculiarlyquantum-mechanicalway,anatomisticaccountofthisdefinitenessofcompositesystemswhosepartsareindefinite.

Theaccountdrawsuponouranalysisofactualityintermsofphysicallypossibleworlds.Inthecaseoftheheliumatom,thetotalangularmomentumalongadirectioninspacemustbeexactlyzeroinatwo-componentsystemwhen,ineachpotentialstatecontributingtoasuperposition,theangularmomentaofthepartshaveequaland

oppositevalues.Thisexampleillustratesageneralfeatureofthedefinitenessofcompositesystems,eventhosesystemsthatarethesubjectsoftheEPRexperiment.ThetotalvalueofanyadditivepropertybecomesexactwhenthepotentialvaluespossessedbythepartsadduptothesametotalineachoftheQ-possiblestatesthatcontributetotheoverallstateofthesystem.Thus,evenwhenthewholeisdefinitewithrespect

tosomepropertywhilethepartsequivocate,thedefinitevaluedisplayedbythewholeisproducedbythecorrelatedpotentialitiesoftheparts.IneveryQ-possibleworldthepropertyofthewholeisthesimpleoutcomeofwhatthepartsaredoing.

Nonseparability.

InexperimentsoftheEPRtype,whentwopartsofasystempossesscorrelatedpotentialstates,anymeasurementthatcausesoneparttoactualizejustoneofitspotentialstatesalsocausestheotherparttoactualizeitscorrespondingstate.Boththeoryandexperimentshowthatthesecorrelatedactualizationsmayoccurevenwhenthetwopartsareseparatedbyalargedistance.Aswehaveseen,whenacompositesystemwhosetotalangularmomentumisdefinitelyzeroseparatesspontaneouslyintotwopartsmovinginoppositedirections,eachpartcarriestwopotentialvalues,positiveandnegative,forthisproperty,andthesevaluesmayberealizedalonganinfinitenumberofpotentialaxesperpendiculartothelineofflight.Foreachdirection,thepositivepotentialvalueforonepartcorrelateswiththenegativepotentialvaluefortheother.Now,supposethatthefirstpartinteractswithameasuringdeviceandsomewhatlater,ontheoppositesideoftheapparatus,thesecondpartencountersanothermeasuringinstrument.Thetheoryallowsbothdevicestoenterindeterminatestates,composedofthecorrelatedpotentialoutcomesproducedbythepotentialstatesofthetwomeasuredparticles.Butweknowinfactthatthetwomeasuringinstrumentsenterstateswithdefinitevaluesatleasteverydeviceeverexaminedbyaconsciousobserverhasdonesoandhencethattheactualizationsoccur.Accordingtoanobjectiveinterpretationofquantummechanics,eachactualizationisaneventoccurringintheobservedsystem,notmerelyinthemindoftheobserver;Heisenberg'sandSchroedinger'sopposingconjecturesaboutthetransitiontoactualityagreeatleastonthatpoint.Whetherthefirsteventresultsfromtheparticle'sencounterwiththefirstmeasuring

instrumentorfromtheobserver'sinspectionofit,theantecedentconditionsdonotsufficetodeterminethevaluerecordedbytheinstrument.Wemustthereforeconsidertheresulttobepartiallyuncaused.The"choice"ofapositiveornegativevalueseemstobefreelymadebythemeasuredelectron.Genuinenoveltybreaksintothecausalweb.

However,thevaluerecordedinthesecondinstrumentiscompletelydetermined,yetnotentirelybylocalinfluences.Ifthefirstmeasurementyieldsthepositivevalueinacertaindirection,andifthesecondinstrumentpointsalongthesamedirection,thenitiscertaintoregisterthenegative,evenifthesecondmeasurementhappensonlyinfinitesimallylaterthanthefirst.Thesearepuzzlingfacts,fortworeasons.Inthefirstplace,thefirstmeasurementhelpstodeterminetheoutcomeofthesecond,evenwhennoemissary,movingnotfasterthanthespeedoflight,couldpassbetweenthem.Inaddition,iftwoeventsoccurnearlysimultaneouslyinoneinertialreferenceframe,theyoccurinreverseorderinothers;thus,wecannotpointunequivocallytotheagentofthesupposedaction.Inattemptingtoreducethiscompoundmeasurementtoapairofcausallyconnectedsinglemeasurements,wefindourselvesspeakingofputativecausalinfluencesthatpropagatemysteriouslyfromplacetoplacewithoutdelayandwithnoneedofphysicalintermediaries.

Itisnotself-evident,however,thatthecorrelationofthesetwomeasurementsresultsfromanordinarycausalactionofoneinstrumentontheother.Isuggestthatthefailureofthisattemptedreductionrevealsnotaflawintheatomistprogrambutourfailuretoreckonwiththepeculiarnatureofthetransitiontoactuality.

Traditionally,atomismhasroomforonlytwokindsofevents:theshufflingofparticlesfromplacetoplace,astheyassemblethemselvesintopatternedclustersonlytoseparateagain;andthetransformingofparticlesofonekindintoparticlesofanother.Eventhissecondsortofeventisadmittedonlyprovisionally,withtheexpectationthatwhatappearstobeatransformationwillberevealed,followingtheexampleofchemistry,astheregroupingofotherandmorefundamentalparticles.Andthecausalactionofstandardatomismconsistsinnothingotherthantheinfluencingofsomeofthesemotionsandtransformationsbyothers.Quantummechanicsmakesnoexceptionto

thisrule;indeed,withineachQ-possibleworlditdescribes,thetheorytellsnothingbutthestandardsortofstory;theordinarycanonsofcausalityholdsway.Thetransitiontoactualitydoesnothappeninanyofthem;instead,itsimplyprunestheluxuriatingbranchesofpotentiality.Thepruninghookdoesnotswingalongabranch,as

causalinfluencesflow,butswingsacrossit.Nordoesthetheoryitselfcommandthetrimming;thattaskfallstothepersonwhowieldsthetheory,whoknowsthatameasurementhasdeliveredoneofitsR-possibleresultsandnottheothers.Atthetimeoftheactualizationthetheorizersimplifiesthestoryheorsheistellingwiththeaidofquantummechanics;presumably,therefore,theobjectcorrespondinglyrelinquishessomeofitsrealpossibilities.

Certainly,akindofholismisdisplayedinthetransitiontoactuality.Buttheunittowhichthisquantum-mechanicaleventpointsisnotingeneralacomposite,macroscopicthingintheusualsenseofthattermingeneralnot,forexample,abiologicalorganismorapieceofmachinery.Rather,theunitseemstobeanentireQ-possiblescenarioforthecourseofevents.Itinvolvespiecesofmanyscatteredcommonsensethings.Manysuchunitsparticipateinanactualization;allbutoneorafewparticipatebybeingcutoff,thusceasingtocontributetothetotalpicturefromthemomentoftheactualizationonward,andtherestparticipatemerelybyescapingthegeneraldestruction,thuscontinuingtocontribute.

Yetsomeactiveentitymustbedoingthismetaphysicalviticulture.Ifitcouldbeidentifieditwouldqualifyastheagentofanewkindofcausalinfluence,operatingfromoutsidethemanifoldofspace-time.Aswehaveseen,HeisenbergandSchroedingernominaterivalcandidates.Buttheirdisputeleadsusawayfromthepresentthemeofholisminthequantumtheory;letusthendeferthatissueuntilwehaveconsideredhowquantummechanicstreatsinteractionsamongcompositethings.Thekindofholismthatweseekwouldsupportourintuitionthathumans,andpossiblyothercompositethingsaswell,participateincausalinteractionsasunits,notjustassumsoftheactivitiesoftheirparts.Toseewhatthequantumtheoryhastosayonthissubject,wemustlookatitsprescriptionforhowtodescribethecausalencounterofonestructuredcollectionofparticleswithanother.

Likeanyothermechanicaltheory,quantummechanicspermitsustonameconglomeratesasunitsanddescribethemintermsofaverageorsummedpropertiesforconvenienceorbywayofapproximation,tosimplifyourdescription.Thatpermissionsignifiesnothingabouttheantireductiveresourcesofthetheory.Rather,thequestionisthis:Doesthetheoryrequireus

sometimestodesignateentirecompositethingsasunits,inorderproperlytodescribetheirinteraction?Towhatsortofunitaryentitiesdoesthetheorycommitus?

TheOntologicalCommitmentoftheTheory

LikeNewtonianmechanicswithitsthreelawsofmotion,quantummechanicsbuildsonabasiclaw,inthiscasetheSchroedingerequationoritsequivalent,whichpredictsthebehaviorofasystemonlyifitscompositionisspecifiedintheboundaryconditions.Bothclassicalandquantummechanicsdictatetheformofthespecification.TheobjectsarespecifiedbymeansoftheforcefunctioninthecaseofelementaryNewtonianmechanics,theHamiltonianfunctionintheHamiltonianreformulationofclassicalmechanics,andtheHamiltonianoperatorinquantummechanics.WhenapplyingNewtonianmechanicstoanyspecificsystem,onetreatsNewton'slawsortheirequivalentsasaprescriptionforhowtowritethebasicequationofmotionofthesystem.Newton'slawscontainablankspace,thefillingofwhichturnsamereformforadifferentialequationintoaspecificequationforthesystemunderconsideration.Similarlyinquantummechanics,theSchroedingerequationprescribeshowtoconstructspecificdifferentialequationsforspecificobjects;theprescriptionformisfilledinbywritingtheHamiltonianoperatorappropriatetothesystem.Thisoperatordefinestheobjecttowhicheachquantum-mechanicaldescriptionapplies.

TheHamiltonianoperator,representingtheenergyofthesystem,consistsoftwomajorparts,oneforthekineticenergyandoneforthepotentialenergy.Thekineticenergyexpressioniswrittenasthesumofthekineticenergiesoftheparts,andthepotentialenergy(liketheforcefunctioninclassicalmechanics)representstheinteractionsamongthem.Ifascientifictheoryrevealsitsontologicalcommitmentsbytheentitiesitquantifiesover,thentheHamiltonianoperatorin

quantummechanics,likeitsequivalentsinclassicalmechanics,definesaphysicalsystemasasetofinteractingparts.Theeventsthattranspirewithinacompositesystemarerepresentedbythequantumtheoryasthecombinedmotionsandinteractionsoftheparts.Althoughitdepartsfromclassicalatomisminmanyrespects,onthisfundamental

issuequantummechanicsstandssquarelyontradition.Wefind,therefore,noreasontomodifytheclassicaldictumthatawholesimplyiswhatitspartsdothatalivingorganism,forexample,issimplyoneoftheimmenselycomplexpatternedmotionsthatatomsgenerate.

Butwhatdoesthetheorytellusaboutinteractionsbetweenapairofcompositeobjects?Ifquantummechanicsistorestoretheobjectsofeverydayexperienceourselvesincludedtoasolidontologicalfooting,itshouldjustifyourcommonsensetreatmentofthemasunitarycausalagentsintheirinteractionswithothermacroscopicthings;andthejustificationshouldproceedbyappealingtothewaythingsare,nottoapproximationsmadeforthesakeofconvenience,orbyreasonofthelimitationsofourabilitytocalculateuponlargemassesofdata.

Queriedinthisway,however,quantummechanicsprovidesnoreasontoregardcompositethingsasunitaryagents.WhatwemighthopetofindandwhatwouldcertainlyresolvetheriddleofcausalagencyinamannerfavorabletoourselveswouldbeaHamiltonianthatquantifiesovercompositesystems(someofthem,anyway)asunits,representinginteractionsasoccurringatleastonoccasionbetweensystems,notalwaysandonlyamongtheirparts.Instead,wefindthatthequantum-mechanicalanalysisofapairofinteractingsystemsemploysasingleHamiltonian,whichquantifiesoverthesamebasicpartsasdidtheindividualHamiltoniansoftheseparatesystemsbeforetheybeganinteracting.Forexample,eachindividualhydrogenatomofanoriginallynoninteractingpairispicturedasaprotonandanelectron.Whenthetwoatomsinteracttoformahydrogenmolecule,theplotmaythickenbuttheplaybillstilllistsentitiesofthesametype;theinteractionispicturednowasaneventinvolvingtwoprotonsandtwoelectrons,thatis,fourentities,whichresideontheoriginaldescriptivelevel.Causalagencycontinuestobedescribedastheinfluenceofparticleuponparticle,andtheactionsofonecompositethingintouch

withanotherareshowntobetheactionsoftheparts.

Ahigherlevelofdescriptionthatdesignatesacompositesystemasanagentissimplynotwarrantedbythequantum-mechanicaltreatmentofinteractionsamongcomposites.Theexactanalysisofaninteractiondoesnottransfercausalagency

toeitheroftheinteractingsubsystemsasunits.Soweseethattheatomistreductionprogramcanbeimplementedalsobythenewertheory,atleastinthisrespect.

Nevertheless,quantummechanicsseemstodepartdecisivelyfromtheNewtonianlinebyreservingachairforconsciousness.Operatingwithintheoldertheory,onecouldisolatequestionsofmentalityfromdiscussionsofbasicphysicalprocessesandthusplausiblydeferthemind-bodyproblemuntilthefinal,mopping-upstagesofthereductionistprogram.Thatdeferralnolongerlooksplausible.Letustakeacloselookattheallegedlysubjectivefeaturesofquantummechanics;perhapswecanusethemtoputuparadicallynewstyleofdefenseagainstthemechanisticreductionofhumancausalagency.

TheAllegedActionofConsciousness

Quantummechanicssuggeststwopossiblelinesofargumentthatcouldleadtoamentalisticretorttoreductionism.Oneofthemimputessubjectivitytothetheorybecauseofthecentralplaceitaccordstoprobability,aprimafaciesubjectiveconcept.Theotherallegesthatthetheoryrequiressomecausalagenttotakeonanassignmentthatnoatomorgroupofatomscouldperform,onethatappearsuniquelysuitedtoconsciousness.Letusconsider,first,twopossibleintrusionsofsubjectivity.

IsQuantalProbabilityObjective?

Wigner(1961)buildsanantireductionisticargumentupontheprobabilisticnatureofquantummechanics,claimingthatafundamentalmechanicaltheorythatgivesanessentialplaceintheworkingsofnaturetoprobabilityplaceshumansubjectiveexperiencesatthecenteroftheworldratherthanatitsperiphery,whereatomisticmaterialismmusthaveit.Aswenotedabove,Heisenbergattemptstoparrythissortofargumentbyproducinganobjectiveinterpretationof

probabilityasthatconceptfunctionsinthequantumtheory.Sowemustask:DoesHeisenberg'spotentialismsteerclearofsubjectivity?

Heisenberg(1958)intendsittodoso."Theprobabilityfunction...containsstatementsaboutpossibilitiesorbettertendencies('potentia'inAristotolianphilosophy),andthesestatementsarecompletelyobjective,theydonotdependonanyobserver"

(p.53).Heisenberg'sobjectiveinterpretationofprobabilityfindsanallyinthemoreextensivelydevelopedpropensitytheoryofKarlR.Popper(1959;1974).Popperdefinespropensitiesas''realdispositions;dispositionsthatdeterminerelativefrequencies...ofanyoccurrencesyoumayconsider''(1974,p.1130).Popper'swayofobjectifyingprobabilitywillworkforaphysicalsystemthatdoesnotobeystrictlydeterministiclaws.Itsbehaviorinthefutureisnotmerelyanunfoldingofitspresentstate.Atsomeorperhapsallmomentsinitshistory,itfacesseveralrealoptionsregardingwhattodonext,independentlyofwhatwehappentoknowaboutit.Ateachmomenttheobjecthasinherenttendenciestofollowoneortheotherofitspossiblepaths.Ifitsbehaviorfollowsstatisticallaws,wecanassignquantitativemeasuresofprobabilitythatserveaspredictionsoftherelativefrequencieswithwhichthevariouspossibilitieswillberealizedinasequenceofrepetitionsofthepresentconditions.Now,thequantumtheory,unlikeNewtonianmechanics,paintsaradicallyindeterministicpictureofthephysicalworld.Ifthetheoryiscorrectandcomplete,thenwearejustifiedinlocatingtendenciestowardmutuallyexclusivealternativesinsingleexternalobjectsthemselves,independentlyofthecontentsofourstoreofknowledge.Heisenberg'sandPopper'sinterpretationssuccessfullycounterantireductionisticargumentsthatattempttobuildonthequantum-mechanicaluseoftheconceptofprobability.Inanirreduciblyindeterministictheory,probabilityneednotentailsubjectivism.

DoestheTransitionOccurObjectively?

Amoredifficultchallengeremains.Heisenbergcannotavoidintroducinganewkindofeventintohisobjectivepictureofthequantumworld,namely,thetransitionfrompotentialtoactualvaluesofthemeasuredpropertiesofasystem.Thechallenge,calledthemeasurementproblem,arisesbecausethequantumtheoryassignsaprobabilityamplitudetoeverypossibleconfigurationofasystemand

goesondoingsoforever.Nowheredoesthetheoryhintthatsomeoftheaccumulatinglayersofpotentialityarescrubbedawayinthesenovelevents,nordoesittelluswhentheymightoccur.Buthappentheymust,fortheconsciousobserverneverentersastateinwhichexperiencingsomethingsharesthestagewithexperiencingitscontrary.Whendoespossibilitybe-

comeactuality,andwhatobjectoragentbearsresponsibilityforthetransformation?

Schroedinger's(1935)parableofthecatproposesthehypothesisthatactualitybreaksinattheinterfacebetweenconsciousnessandtheworldofatoms.Becauseconsciousexperiencebyitsnaturewillacceptnoneofthemultiplicitythatotherwisefillsuptheworldofmaterialobjects,partoftheclutterisclearedoutwhenevermaterialthingsmakecontactwithmind.Heisenbergattemptstoparrythismentalisticthrustbyinsistingthatthetransitiontoactualityoccursatthepointwheretheatomicobjectmeetsthemeasuringdevice,hencethatitis"notconnectedwiththeactofregistrationoftheresultbythemindoftheobserver"(1958,p.55).

Ifmindscausethetransitiontodefiniteness,thenquantummechanicshasananswertothequestionofwhetherhumanbeingstranscendandunifythecausalactionsoftheiratomicparts.Minds,inthisview,takeahandintheconductoftheworld'saffairsnotbyspinningwithintheatomicmachinerybutbyexertinganewkindofinfluencefromwithout.However,ifthetransitiontoactualitygoesonindependentlyofminds,thisfeatureofquantummechanicsshedsnonewlightonquestionsaboutunitarycausalagency.Consequently,anantireductionisticargumentbasedonthisfeaturemustproceedbydemonstratingthegreatervirtueofSchroedinger'sversionofthetransitiontoactuality.

PopperianIndeterminism

Beforetakingupthattask,however,ImustfirstshowthatHeisenbergandSchroedingerdifferoverasubstantiveissue,notamerepseudoquestion.Popper(1967)arguesthatquestionsaboutwherethetransitiontoactualityoccursarespawnedbyamistakeninterpretationofprobability,fromfailingtorecognizethatprobabilitiesareassigned

inquantummechanicsrelativetospecifiedconditionssuchasthearrangementoftheexperimentalapparatusandtheinitialmotionsofitsparts.Probabilities,inPopper'sexplication,refertoobjectivedispositionsorpropensitiesintheapparatusitself;nevertheless,thesuddenchangeinthevaluesweassigntothepossibleoutcomesofanexperimentdoesnotreflectanobjectiveoccurrence.Instead,whathappens

isashiftinourdescriptivefocus,fromconditionalprobabilitiesthatrefertotheinitialstagesoftheexperimenttoprobabilitiesthatrefertolaterconditions.Beforeturningtothedebateovertheagentsofactualization,ImustfirstshowthatPopper'sargumentdoesnotdissolvethequestionatissuebetweenHeisenbergandSchroedinger.

Popperconstructshisexplicationofprobabilityaspropensityaroundthreeprinciples:(1)Propensitiesareinherenttendenciesinthings,notmerefeaturesofourknowledgeorlackofit.(2)Propensitiesarepropertiesofsingularevents,notjustofclassesorsequencesofthem.(3)Propensitiesareassertedhypotheticallyofphysicalsystems,thehypothesisbeingtestablebyrepeatedtrialsoftheexperimentstowhichtheyareassigned(Popper1959).Thesethreefeaturesalsocharacterize(albeitimplicitly)Heisenberg'sconceptofpotentialityastendency,buttheretheanalogyends.WhereasHeisenbergviewsthesimultaneoustendenciesofathingtodoanactionandallofitsalternativesasapeculiarfeatureofquantummechanicsandasevidencethatsuchthingshaveadifferentmodeofexistence(thepotential)thantheobjectsdescribedbyordinarycommonsense,PopperclaimsthattheconceptofpropensityappliestoNewtonianparticlesaswellastoquantum-mechanicalonesandthat,therefore,nonewmodeofexistenceisintroducedbyquantummechanicsandnotransitionbetweenmodesneedperplexus.Becausethesubsequentdiscussionwillturnonthenatureofquantum-mechanicaltransitionsfromthepossibletotheactual,wecannotignorePopper'sclaimthatsucheventsoccuralsoinaNewtoniancontext.Letustesttheclaim.

CananindividualtrialofanexperimentonNewtonianparticleshaveanobjectivetendencyorpropensitytowardtwoormoremutuallyexclusiveoutcomes?Surelynot.InNewtoniandeterminismthefutureofanindividualrunningofanexperimentisalreadyfixedwhentheobjectiveinitialandboundaryconditionshavebeensetup.Givenitspresentstate,whateveritmaybe,anindividualNewtoniansystemis

alreadycommittedtojustoneofthecoursesofactionweinourignorancereckonpossible.Consequently,inanyindividualtrialoneandonlyoneoutcomeiscertaintofollowwhichoneweusuallycannottell,becausewedonotknowallthetruthabouttheinitialstages.OnlyourlackofknowledgeaboutaNewtoniansystemjustifiesourspeakingof

probabilities;hence,theseprobabilitiesarenotobjectivedispositionsinthesingularcase.WhenappliedtoaNewtoniansystem,thesecondofPopper'sthreeprinciplesconflictswiththefirst.

Italsoconflictswiththethird.PropensitiesinPopper'sanalysisareconditionedbytheexperimentalarrangementtowhichtheyadhere,thatis,bytheinitialandboundaryconditionsofclassicalorquantummechanics.Andahypothesisaboutpropensitiesmustbetestedbyrepeatedtrialsoftheexperiment.Muchdepends,then,onwhatcountsasarepetition;andthatinturndependsonhowcloselywespecifytheconditionsinourdescriptionoftheexperiment.Ifwecharacterizetheexperimentsomewhatloosely,bynotspecifyingtheconditionsdowntothemostminutedetail,thenstatesofaffairsthatdifferobjectivelyinpropertiesthataffecttheoutcomeoftheexperimentwillfitasingledescription,andwewillcountthemasreplicasoftheexperiment.Repeatedtrials,thusdefined,willyielddifferentresults;consequently,propensitiestowardmutuallyincompatibleoutcomesmaybeattachedobjectivelytothesortofentitythatthisdescriptionsinglesout.However,itpicksoutnotanindividualexperimentalapparatusbutaclassofthem,akindofexperiment.

IsubmitthatobjectivepropensitiespertainonlytoclassesofNewtonianobjects;singularcasesadmitonlyofsubjectiveprobabilities.WecannotfindamodelforPopper'sconceptofpropensityinNewtoniandeterminism,becausearigidlydeterministicworldcannothaveobjectivepropensitiesthatbelongtosingularevents.

PeirceanIndeterminism

However,Popperianpropensitiesdooperateinanindeterministicworldwhosefutureisnotcontainedinitspresentstate.Nowthatquantummechanicsiswellestablished,wecanchoosebetweentwo

majorandverydifferentkindsofsuchworlds.Anexampleofthefirst,prequantalsortisproposedbyCharlesSandersPeirce(1892).HesuggeststhatmaterialobjectsmayobeylawsofNewtoniandeterminismonlyapproximately,deviatingrandomlybutcircumspectlyfromthematanymoment,asifbywhim.InPeirce'sspeculation,whateveramaterialobjectmay

doitdoesdefinitely,withnoneoftheequivocationwefindinquantummechanics.ThatPopperhasinmindanindeterminismofthissortcanbeinferredfromthewayheusesretrodictioninaparticlediffractionexperiment(1967,pp.26,27):Aparticlemovesthroughasingleslittowardaplanararrayofdetectors,whereitlocalizeseventuallyatoneofthem.Thequantumtheoryassignsprobabilityamplitudesatthedetectorsforeachmomentintheparticle'shistory.AccordingtoPopper,theseamplitudesrepresenttime-independentprobabilitiesthatarerelatedonlytotheconditionsobtainingatthestartoftheexperiment.Later,whentheparticleadoptsanactuallocationatsomedefinitepoint,weusethatdatumtoestablishwhattheparticle'sactualpathandvelocityhavebeeninitsjourneyfromtheslittothedetectingsurface.Relativetotheinitialconditions,theparticlewasdisposedtomoveinmanydifferentdirections;butrelativetotheconditionsobtainingduringitsflight(conditionsthatwerethenunknown),itwasdisposedonlytomovealongasingledefinitepathandtostrikejustonepointinthefinalplane.Wediscoverwhichpathhasbeentheactualonewhentheparticlestrikesthedetector.Theearlierconditionswereunknowntousatthetime,butthemeasurementrevealsthemafterthefact.Althoughitwasnotdeterminedtopursueitschosenpathatthemomentitemergedfromthesource,ithadmadeitschoicebythetimeithadpassedthroughtheslit.

APeirceanindeterminismalsoaptlymodelsPopper'sthoughtexperimentofaballdroppingthroughapinboardthesortinwhichtheballsinrepeatedtrialsfallintovariousbinsatthebottom,withfrequenciescorrespondingroughlytothecoefficientsofthebinomialtheorem.Letusfollowanindividualtrialofthisindeterministicpinboardexperiment.Aball,onstrikingthefirstpin,mightreallymightbounceinseveraldifferentdirections,forthecollisionconservesmomentumonlyapproximately;consequently,boththeball'sangleof

approachtothenextpinanditstrajectoryafterstrikingitareevenlesswelldeterminedbytheinitialconditions.Inasingletrialoftheexperimenttheballsettlesintoabininthebottomrowbyfollowinganerraticbutdefinitepathasitbouncesfrompintopin.Inasecondsingletrial,whichstartsoutasanexactreplicaofthefirstexacttothemostminutedetailtheballexercisesadifferentoption,strikingotherpinsandarrivingatanotherreceptacle.Atthebe-

ginningofeachindividualtrialtheballpossessesobjectivedispositionsorpropensitiestoreacheachoneoftheavailablebins,simplybecauseitsfutureistoalimiteddegreestillopen.Therefore,theeventoftheball'sarrivingfinallyatacertainbinhasanumericalprobabilityrelativetotheconditionsobtainingatthestartoftheexperiment.Now,thisassignmentofconditionalprobabilitiesdoesnotchange;itmaybetestedbyrepeatedlyrestoringthesameinitialconditionsandrecordingtherelativefrequencywithwhichtheballarrivesinthatbin.Becauseeachrepetitionoftheexperimentduplicatesexactlytheobjectiveconditionsofalltheothers,thepropensitybelongsobjectivelytotheballinthatsituation.Thefunctionthatrepresentstheprobabilitiesofarrivinginvariousbinsistheanaloginthisexperimentofthestatevectorinquantum-mechanicalexperiments.Nothinglikeacollapseofthewavepackethappenshere,becausetheconditionalprobabilitiesdonotdependontime.

Wecan,however,constructsomethingresemblingthereductionofthequantum-mechanicalwavepacket.Letusdefineatime-dependentprobabilityoftheball'sarrivinginthebin,relativetothechangingconditionsthatobtainateachmomentastheexperimentdevelops.Atthestartthisnumberisthesameastheprobabilityalreadyreferredto.Butastheexperimentprogressestheconditionschange,objectively.Astheballcollideswiththefirstpinitpossessesobjectivedispositionsbothtomovetotherightandtomovetotheleft,butitchoosesjustoneoftheseoptions.Anditgoesonmakingsuchchoicesateachstageofitsjourney.Justastheballstrikesapininthebottomrow,itmustchoosebetweenthetworeceptaclesimmediatelytoitsrightandtoitsleftitcannolongerreachtheothers.Adifferentprobabilityfunctionappliestothefinalconditionsthandoestothoseatthebeginning.Attheendalltheprobabilitiesarezeroexceptthoseforthetwobinsjustbelowthepinnowbeingstruck,andforeachof

thesetheprobabilityisnowone-half.Theexperimentconcludeswiththeballfirmlynestledin,say,thethirdbin.Whenwecomputetheprobabilityoffindingtheparticlesinanybinrelativetothefinalconditions,wefindthatthefunctionhas"collapsed"tothevalueunityforthethirdbinandzeroforallothers.Inassigningaunitprobabilitytojustoneofthepossibleoutcomesandzerototheothers,relativetothefinalconditions,wedonomorethanassertthatifwelookagainwe

willstillseethesameresult.Noimpenetrablemysteryplaguesushere;ofthesimilarcaseoftheflippingofacoinPopperenunciatesthe"trivialprinciple...thatifwelookatourpennyasecondtime,itwillstilllieasbefore"(1967,p.37).

This,then,isPopper'sreconstructionofHeisenberg'stransitiontoactuality:Theobjectivepossibilitiesinanindeterministicsystembecomemoreandmorerestrictedastheexperimentalsituationdevelops.Thediscontinuoustransition,heclaims,consistsofourshiftingourattentionabruptlyfromonesetofconditionalprobabilities,whichrefertotheoriginalstageoftheexperiment,toanotherset,whichrefertotheterminalstage.Andthe"statevector"thatis,thesetoftime-dependentconditionalprobabilitieschangesnearlycontinuously,becausechoicesaremadecontinuallyastheexperimentprogresses.

Popper'sanalysisiscertainlycorrectwhenappliedtothesortofindeterminacyproposedbyPeirce,whichcanbeunderstoodintermsofR-possibilityalone.Andthecontinualreductionofobjectiveoptionsdoesseemanalogoustothereductionofpossibilitiesinquantummechanics.ButinfacttheindeterminateworldofquantummechanicsdiffersradicallyfromtheworldenvisionedbyPeirce,soradicallythattheanalogyfails.R-possibilityisnotenough;weneedQ-possibility,too.

QuantumIndeterminism

ToseehowfarPopper'sanalogycanbedriven,andwhereitbreaksdown,letusalterSchroedinger'scatstorybysubstitutingforthecatanautomaticmechanism.Weplacearadioactivenucleus,anemitterofelectrons,nearacrystalandaGeigertubearrangedsothatanelectronshootsoutfromthenucleus,scattersfromthearrayofatomsinthecrystal,andeitherhitsormissesthetube.Ifthetubereceives

theelectronitsendsanelectricalsignaltoamechanismconcealedwithinabox.Thismechanismcausesasmallhammertostrikeasilverwatch,whichwassetrunningatthebeginningoftheexperiment.Thewatchstopswithitshandspointingtothetimeoftheevent.If,afteranhourhaspassed,nosignalhasbeenreceivedfromtheGeigertube,thissamemechanismactuatesanotherhammer,whichstopsagoldwatch.Aftertwohourshavepassed,ahumanobserverliftsthelidofthebox,looksinside,lowersthelid,thenliftsitandlooks

again.ThiscontrivancematchesPopper'sthoughtexperimentwithapinboardinfouressentialfeatures.Itincludesthetwomeasurementsthatoccurinsuccessiveinspectionsbytheobserver.Theapparatusincludessomethinglikethepinboard,namely,alatticeofatomsinthecrystal.Third,thequantum-mechanicalprobabilitiespertainingtothepossibleoutcomesoftheexperiment(forexample,theGeigertube'sbeingdischargedornot)areassignedrelativetotheconditionsobtainingatthebeginningoftheexperiment;hence,asdefined,theydonotvaryasthetrialprogresses.Theseconditionscanberepeatedexactlyinsuccessivetrials,withthesamestatevectorapplyingineverycase.Finally,thephysicallypossibleoutcomespickedoutbythetheoryshowthemeasuringinstruments(theGeigertube,thehammer,thewatches,andthecentralnervoussystemoftheobserver)onlyincorrelatedstates:Inonesuchpossibility,theGeigertubelodgestheparticle,thegoldwatchtickson,thesilverwatchisstoppedatapositionindicatingthelapseoffifteenminutessincethebeginningoftheexperiment,andtheobserver'sbrainencodesbothalivingimageofthewatches(fromthesecondinspection)andamemoryofthesamescene(fromthefirst).AnotherQ-possiblepicturepaintedbythetheoryduplicatestheonejustmentionedexceptthatthehandsofthesilverwatchindicateadifferenttime;stillanothershowstheGeigertubeuntouched,thesilverwatchstillrunning,thegoldwatchstoppedatexactlyonehour,andtheobserver'sbrainrecordingboththememoryandthecurrentimageofthewatchesinthiscondition.Innoneofthesedistinct,Q-possibleworldsdoesthebrainoftheobserverencodealivingimageincompatiblewiththememoryitretains,nordothesebrainstatesfailtoagreewiththestateofthewatches.Thus,wemayconcludethat,inanyphysicallypossibleworldinwhichtheatomicparticleactivatestheGeigertube,thefirstmeasurementrecordsthatfactandthesecondmeasurementcorroboratesthefirst.

ItishardtoresistcarryingthisinterpretationonestepfurtherbyassumingthatameasurementrevealstheprioractualityoftheQ-possibleworldtowhichtherecordedresultbelongs.ThatwouldbeappropriateinPeirce'sindeterminism,which,althoughitcrackstherigidcausalityoftheNewtonianworld,retainsitsdefiniteness.Theseveralthreadsofnarrativetowhichweassignprobabilitiesinadefiniteuniversearerealizedinsometrialsof

anexperimentandcontributenotatalltootherstheballfindsitswaytoabinbymeansofonezigzagpathinonetrialandadifferentpathinanother.Pursuingtheanalogy,wemaysupposethatinagiventrialofthisexperimenttheelectronreachestheGeigertubebycollidingonebyonewiththemembersofonesubsetoftheatomsinthecrystallattice,andinanothertrialitfailstohitthetubebecauseittakesanotherpaththroughthelattice.Liketheballinasingletrialofthepinboardexperiment,theelectroncontinuallymakeschoices,thediscardedoptionsmakingnofurthercontributiontoitsprogressinthatparticulartrialuntilfinallyoneandonlyoneresultwinstheday.

Nowmanyexperimentswithquantumprocessesdonotrevealtheerrorofsuchaviewofprobability.Butexperimentsininterference,ofwhichthisatomic"pinboard"experimentprovidesanexample,revealthattheworldaccordingtoquantummechanicsisneitherdeterminatenordefinite.C.J.DavissonandL.H.Germer(1927),forexample,intheirstudyofthediffractionofelectronsbyanickelcrystal,foundaninterferencepatterninthescatteredbeam:Theelectronsavoidregionsofthedetectingsurfacethattheycouldeasilyreachiftheycollidedwithsingleatomsorsequencesofsingleatomsofthecrystal.Thethreadsofthequantumnarrativecontributeallofthemtoeachsingulartrialoftheexperiment.Normally,thestrandsseparatepermanently,andwedonotexperiencedifficultywithourmistakenassumptionthatjustoneofthem(wedonotknowwhich)obtainsinanysingularcase.Butwhenparticlesdiffractthroughslits,orcollidewiththeatomsinacrystal,adensenewfabriciswovenfromtheonlytemporarilyseparatedthreads;andwefindtheproofoftheirreassemblyandthereforeoftheircontinuedcontributionthroughouttheprogressoftheexperimentinthenonarrivaloftheparticle,inalltrials,atpointsonwhichitwouldsometimeslandifitfollowedjustonepathineachtrial.

Thestartlingfeatureofthequantum-mechanicalpictureofrealityis

neitheritsindeterminismnoritsuseofconditionalprobabilities.Indeterminismisfairlyeasytobelieve,andPopperarguespersuasivelythatbothclassicalandquantum-mechanicalprobabilitiesrefertothecircumstancesinwhichthedispositionscometoberealized.Rather,theradicalbreakbetweenthequantumworldandtheworldofclassicalcommonsenseoccursovertheissueofmultiplicityversusdefiniteness.Inprequantalindeter-

minism,freedispositionstodoornottodosomethingpointentirelytowardthefuture,referringtocausalsequencesthatanagentmayinitiateatagiventimeundertheconditionstheninforce.Anagentwiththatsortoffreedomhasnotonlycounter-factualbutalsorealpossibility.IhavecalleditR-possibility,todistinguishitfromtheC-possibilityofNewtoniandeterminismandfromHeisenberg'sradicallynewconcept,Q-possibility.IfanagentcanR-possiblyperformanactionatacertaintime,andofcourseR-possiblynotperformit,too,thenwhenthetimehaspasseditmustbethecasethattheactioneitheractuallywasperformedor,thoughitmighthavebeen,actuallywasnotperformed.Realpowerabidesintheagent,butthe"choice"toexerciseitornotmustbemadeatthetimeand,oncemade,isrecordedindelibly.NowweknowfromtheDavisson/Germerexperimentthatitwouldbefalsetosay,lookingbackonthecompletedprocess,thattheparticleactuallycollidedwithagivenatominthecrystal(forthatwouldentailthatitactuallydidnotbounceofffromanyotheratom)andequallyfalsetostatethatitactuallydidnotcollidewiththatatom.Thescatteringfromatomnumber1figurescausallyinthestorywetelltoexplainwhyeverydeflectedparticleavoidedcertainregionsofthephotographicplate,andsodoesthescatteringfromatomnumber2,andsoon.TheseQ-possibilitiesarenotsimplytherealpowersofcommonsense,notmereoptionsthatthefreelyactingparticleexercisesorrefrainsfromexercisingwhentheopportunitycomes.Commonsenseoptionscrystallizeasthefleetingpresentovertakesthem;thecommonsensepaststandsfirmandsingular.Butinquantummechanicsthemultiplicityisretainedinwhatthemovingfingerwrites.Eventhepastequivocates.

Hence,theprobabilityamplitudeswecalculatewithreferencetotheinitialconditionsofaquantum-mechanicalexperimentdonotadmitofacontinualupdatingastheexperimentwearson.Ifquantum

mechanicsiscorrect,therearenohiddenvariablesthatcouldchangeobjectivelybutundercoverasthesystemevolves.Newconditionalprobabilitiesarenotcalledfortowardtheconclusionofanexperimentnotbecausewehappennottoknow,orforinescapablereasonscannotcalculatethealteredconditions,butbecausetheobjectiveconditionsthemselveshavenotchanged.Evenrelativetowhatthesystemisdoingnow(whateverthatmaybe),longafterthestartofthetrial,theprobability

atsomefuturetimeofagivenoneamongseveralQ-possibleresultsremainsequaltoitsvaluerelativetoearliercircumstances.

Popper'sattempttounderstandquantum-mechanicalpropensitiesasconditionalprobabilitiesofthefamiliarsortdoesnotdojusticetotheradicalmany-sidednessofatomicobjects.Athing'smultiplepropensitiesbelongtoitintrinsicallyandmomentbymoment,notmerelyinrelationtoitsearliercircumstances.Ateachstageofitshistory,andinthismetaphysicallynovelmodeofbeing,theobjectacts(Q-possibly)inseveralmutuallyincompatibleways.

WhatCausestheTransition?

Ifthetransitionoccursobjectively,itmustoccursomewhereandatsometime;presumably,too,somethingmusttriggertheprocess.Wherecouldthiseventoccur,andbywhatagent'saction?Letusconsider,first,Heisenberg'saccount.

Heisenbergadmitsthatthequantalworldpictureislessobjectivethantheclassical.Theobjectivityofprequantalphysicsentailsthebeliefthatwecan''describetheworldoratleastpartsoftheworldwithoutanyreferencetoourselves.''Now,althoughquantumtheory"doesnotintroducethemindofthephysicistasapartoftheatomicevent,"neverthelessthenewpictureis"notcompletelyobjective"(1958,pp.55,56).Whydoeshemakethisadmission?

InsomepassagesHeisenbergsuggeststhatacertainpeculiarityofhumanlanguageisresponsiblefor"theparadoxofquantumtheory,namelythenecessityofusingtheclassicalconcepts"(1958,p.56).Althoughhegenerallyspeaksinthiscontextofconceptsintheplural,herefersnottotheordinaryphysicalconceptsbuttothemetaphysicalconceptofpotentiality.Accordingtothequantumtheory,itistheappropriateconcepttoapplytotheparticles,eventolargesystemsofthem,eventothecollectionsofatomsthatconstitutetheobjectsof

ordinarylife.Yethumanbeingscannotspeakaboutmacroscopicobjectsexceptunivocally,thatis,intermsofactuality.Ifthecategoryofactualityweresimplyimposedonourscientificdiscoursebyconventionorbythelimitationsofthehumanbrain,thenthechargeofimplicatinghumanpeculiaritiesinthestoryaboutnonhumanmatterwouldbewellfounded.ButHeisenbergcannotintendustotake

hisclaiminthatsense.Wedonotlacktheabilitytospeakofordinaryobjectsintermsofpotentiality,andlinguisticconventionscanbetranscended.Thequestionisnotwhetherwehavetheabilitytoutterthembutwhetherclaimsofmultiplicityaretrueofmacroscopicthings.Linguisticpracticeflowsnotfrommerecustombutfromthefactsofhumanexperience.Ourexperiencesofthingsaresingle;quantummechanicspicturesthethingsthemselvesasmultiple:Thereisthe"paradox."Totheextentthatwemodifytheatomicstorybyintroducingelementsofhumanexperience,thequantalpictureisnotcompletelyindependentof"referencetoourselves."Forexample,informationastowhichparticularpotentialeventgetsactualizedmustalwaysbeinsertedintothestorybyappealingtohumanexperience.However,wemayreplythatthisappealisrequiredmerelybytheessentialindeterminismoftheworld.Weneedtofindoutwhichpossibleoutcomehaswonthelottery,butthedrawingmaynonethelesshavebeenconducted,anditsresultrecorded,entirelyapartfromhumanparticipation.Inthatcasetheinvolvementofhumanconcernsinthescientificdescriptionwouldbeminimal,andcommonsenseobjectivitywouldsurvive.Heisenbergclearlyintendsustoadoptthisviewofthenoninterventiveroleofhumanexperience:''Theobserverhas,rather,onlythefunctionofregisteringdecisions,i.e.,processesinspaceandtime,anditdoesnotmatterwhethertheobserverisanapparatusorahumanbeing"(p.137).SoHeisenbergproposesthehypothesisthatdefinitenessenterstheworldsomewhereinthephysicalprocessinwhichtheatomicparticlesinteractwithmacroscopicinstruments,beforehumanobserversengagethemselvesintheprocess.Inthissense,too,subjectivityiskeptatbay.Still,aproblemremains.

Heisenbergpointsoutthatalthoughwemayfreelyenlargethesystembeyondtheatomicobjectsofmeasurementbyincludingdetectors,auxiliarymeasuringapparatus,secondarymeasurersofthefirst

measurers,humansensoryequipment,evenbrains,thequantumtheoryshowsusnothingbutmultiplicitythroughouttheentire"closedsystem,"nomatterhowfarweextenditsboundaries.However,wedofindawaytoputdefinitenessintothestory.Thisisdone"intheCopenhageninterpretationbytheintroductionoftheobserver"(1958,p.137).This"observer"maybeameremachine;hence,nometaphysicalnoveltiesareim-

plied.Evenso,ifwetreatitasanordinarycollectionofparticlestowhichthelawsofquantummechanicsapplyintheusualway,wefailtogetthedefinitenessweseek.Instead,thisobservinginstrumentmustbeintroducedexmachina.Wemustinsistthatthemultiplicitydoesinfactnotobtainbeyondthispointinthemeasuringprocess.Weexemptaportionofthesystem,the"observer,"fromthelawsthatgovernordinaryobjects(p.137).

Buthowcanwelicensetheexemption?Itrequiresaprincipledjustification,arulethatextendsthequantumtheorybyspecifyingtheobjectiveconditionsunderwhichthemultiplicitiespredictedbytheunmodifiedtheoryinfactdonothappen.Toaccommodatetheprogramofmaterialism,thenewrulemustnotimplythatanythingbutatomicparticles,singlyoringroups,participatesinthetransitiontoactualityinparticular,theremustbenohintofanonmaterialagent.

Butthematerialistprogrammayfail.Perhapsdefinitenessdoesresultfromtheinteractionofthemeasuringinstrumentwithaconsciousmind.InwhatfollowsIshallargueforthedualisticalternativebymeansofapeculiarlyvulnerablestrategy.Ishallnotbuildaproof.Rather,havingestablishedinchapter9thatthemindhypothesisisplausible,howeverdistastefulitmaybe,Ishallproceednegativelybyattackingeveryhypothesisofthematerialisticsortthatseemsremotelyplausible.Idonotknowhowtodemonstratethateveryconceivablematerialisthypothesismustfail;butIhopetoargueconvincinglythatthelikelihoodofsuccessalongthatlineisweakindeed.Finally,becauseoneoughtnottoabandonahypothesis,nomatterhowunpromisingithascometoseem,withouthavingamorepromisingalternative,Ishallurgethatwecanadapttothedualistconjecture'sinitiallyrepulsiveflavorbydispellingpartofitandbylearningtoliketherest.

AlternativestotheMindHypothesis

Ameasuringinstrumentiscomposedofparticlesjustlikethosewhosemultiplicityitrevealstous.How,then,canweaccountforitssteadfastrejectionofpotentiality?Ishallconsidersevenstrictlymaterialistichypothesesabouttheprocessofactualizationwhich,Isubmit,exhausttherangeofevenremoteplausibility.Icastthesehypothesesintheformofrulesforactualiza-

tions.Werewetoadoptoneofthem,itwouldfunctionasanadditiontothequantumtheory,namelyasalawgoverningthereductionofthewavepacket.

Rule1.

Everymacroscopicobjectthatwenotice,includingtheobjectsweemployasmeasuringinstruments,existsonlyinthemodeofactualityjustbecauseitisseen,becauseofitspresentorfutureconnectiontooursenses.Theatomicparticlesthatwecannotperceiveexceptbymeansofinstrumentsmayseethewithmultiplepossibilities,butthearrayoflaboratoryequipmentthatweattendtoliesquietlydefinite;awatchedpotentiometerneverboils.

Clearly,Heisenberg'sprogramcannotaccommodatethisrule;for,bymakingcurrentorprojectedperceptionpartoftheconditionsdeterminingwhetheranobjectcanbeactualornot,itinsertshumansensoryorgansandperceptualdispositionsintothemeasuringprocesstheveryresulthisaccountoftheprocessofactualizationisdesignedtoavoid.Whatgoesonintheinteractionbetweenaparticleandameasuringinstrumentoughttodependonlyonwhatitisdoingthenandthere,notonrelationsthatthedevicesustainswithsentientbeings:Neitheritsorigininaninstrumentshopnoritsfutureinspectionbyaresearchassistantcanaddanythingtothepropertiesitcarriestothescene.Rule1failstoconformtoHeisenberg'sprogram.

Rule2.

Everymacroscopicobject,andthereforealsoeveryinstrument,existsonlyinthemodeofactualitybyvirtueofitsbeingacompositething.

Againstthishypothesisstandargumentsproposedinchapter1forcausalinteractionsingeneralandothersproposedinthepresentchapterspecificallyfortheinteractionsofquantummechanics.Theseargumentsshowthatcausalinteractionsbetweencompositeobjects,

orbetweenaparticleandacompositething,canbeunderstoodadequatelyonlyifwedescribetheinteractingsystemsattheleveloftheirparts.Adetector,therefore,doesnotactasawholewhenitswallowsupaparticle;thatinteraction,likeallthatoccuramongcompositethings,canbeadequatelyrepresentedonlybyaHamiltonianthatidentifiestheatomicpartsastheactors.Wecannotmaintaintheviewthataparticleinteractingwithacompositethingengagesinaneventdifferent

inkindfromitsinteractionswithasmallgroupofparticlesofitsownsort.Interactingwithacompositethingjustisinteractingwithsuchparticles.

Besides,counterexamplestothisruleareeasytofind.Wehaveseen,forexample,thatsometimesapairofparticlesjointlypossessesmultiplepotentialities.Evenmoreconclusively,avariationofDavissonandGermer'sexperimenthasbeenperformedwithheliumatoms,eachofwhichiscomposedofnotlessthansixparticles(Estermann,Frisch,andStern1931).Theresultisessentiallythesameasforelectrondiffraction:Whenabeamofheliumatomspassesthroughacrystaloflithiumfluoride,aninterferencepatternforms,showingthateachatomscatterspotentiallyfromeachoftheatomiccentersinthecrystal.Clearly,compositeobjectssometimesexistinstatesofmultiplepotentiality,andrule2iscontradictedbyexperiment.

Rule3.

Macroscopicobjectsareinvariablyactualjustbyvirtueoftheirbeingmacroscopic.

Thisprinciplecanbestatedmoreexplicitlyinthreeversions,withvariousdegreesofstrength,asfollows:First,andmoststrongly,wemightsaythatamacroscopicthingalwayshasactualvaluesofitsmacroscopicpropertiessuchastotalmass,totallinearorangularmomentum,positionofthecenterofmass,andthelike.Second,wemightsaythatamacroscopicthingisactualonlyinthosepropertiescurrentlyunderobservation.Finally,wemightallowamacroscopicobjecttohavearangeofpotentialvaluesforitsmacroscopicpropertiesbutrequirethattherangebesorestrictedastobeindistinguishablebymacroscopicmeasuringinstrumentsfromasingle,definitevalue.

Thesecondversionpushestheproblemofdefinitenessbackfromthedetectinginstrumenttowardtheconsciousobserver.Heisenberg'sprogram,whichaimstomakethetransitiontoactualityanissuetobesettledamongthematerialthingsthemselveswithouttheparticipationofmind,wouldnotbefurtheredbythisconjecture.ItconcedestoomuchtothelineofinterpretationthatleadstoSchroedinger'sconjecture,andIshallnotconsideritfurtherhere.

Considerthefirstandboldestformulation:Themacroscopicpropertiesofamacroscopicthingarealwaysactual.Despitethefactthatthepartsofacompositesystemalwaysteemwithpoten-

tiality,thissuggestioncannotbedismissedoutofhand.Wehaveseenexamplesofdefinitenessconstructedoutofindefinitenesseveninsomeverysimplesystems.Thetotalangularmomentumofthetwoelectronsofaheliumatom,forexample,mayhaveavaluepreciselyzero,thougheachparticlepossesesbothpositiveandnegativevaluespotentially.Alongwiththisprincipleweshallalsowishtomaintaintheconservationlawsofmass-energy,linearandangularmomentum,andtherest,aswedo,forexample,inanalyzingtheEPRexperiment.Nowletusseewhetherthesetwoprinciplescanbemaintainedwithinthelawsofquantummechanicsaswehavethem.

ConsidertheDavisson/Germerexperiment.Thesystemconsistsofanincomingparticleandacrystallattice.Theparticlemaybepreparedinitiallyinastateofdefinitelinearmomentum,asaplanewaveofarbitrarilylargeextensionacrossthewavefront.Suchaparticlehaspreciselyzerovaluesofitslinearmomentumcomponentsindirectionsperpendiculartothepropagationofthewave,andaprecisenonzerovalue,relatedtothewavelength,inthedirectionofpropagation.Intheseinitialconditions,wedescribethetwo-partsystembyassigningvaluesofmomentumandotherpropertiestotheincomingparticleindependentlyofassignmentsmadetothelattice.Initiallytheparticlehasadefinitemomentumbecauseofitsmannerofpreparation,andthelatticehasadefinitemomentumexhypothesi,becauseitisamacroscopicthing.Thereforetheentiresystemhasadefinitetotalmomentum,thesumofthemomentaofitsmacroscopicandmicroscopicparts.

Nowletusapplythequantumtheorytothisexampleofscatteringfrommultiplecentersbyadaptingtheanalysisofthedouble-slitexperiment.Aftersometimehaselapsedthedescriptionofthesystemcannolongerbefactoredintoindependentparts.Thestoryshowstheparticlearrivingatanygivendetectorintheterminalsurfacebyscatteringpotentiallyfromonelatticepointwithapotential

momentumsuchastocarryittothedetector,fromanotherlatticepointwithanotherpotentialmomentumsuchastocarryittothesamedetector,andsoon.Toeachofthesepotentialchangesoftheparticle'smomentumcorrespondsachangeinthecrystal's,sothatthesumoftheparticle'sandthecrystal'smomentaafterthepotentialcollisionequalstheirsumbefore.Weknowfromouranalysisoftheresultinginterference

patternthatthescatteredparticleexistsinasuperpositionofseveraldistinctmomenta,becauseitconvergesfromalllatticepointstoasinglepointonthedetectingsurface.Hence,thelatticepossessespotentialmomentathatrangejustaswidelyasdothepotentialmomentaofthescatteredparticle.Wecannotunderstandtheinterferencepatternwithoutpostulatingthemanyconvergingpotentialmomentaoftheparticle;andwecannotmaintaintheconservationlawwithoutpostulatingcorrespondingdivergingpotentialmomentaforthelattice.

Rule3stipulatesthatthecrystalsimplychangesfromitsdefiniteinitialmomentumtosomedefinitefinalmomentum.Butthescatteredparticle'smomentumislinkedtothecrystal'sbyaconservationlaw,asinthestandardEPRexperiment.Consequently,theparticlemustreduceitspotentialmomentatothesubsetthatcorrelateswiththecrystal'sdefinite,thoughunmeasured,value.Butanysuchsubsetwouldbetoomeagertoaccountfortheobservedinterferencepattern.Becausetheparticlecarriesthesamemomentumintoeachpotentialinteractionwithascatteringcenter,andthecrystalrecoils(onthishypothesis)withjustonedefinitemomentum,theparticlescatterswithpreciselythesamepotentialmomentumfromeachcenter.Butequalmomentaareparallelanddonotconvergetomakeaninterferencepattern.Ifweretaintheconservationlawsandthestandardquantum-mechanicalanalysisofthediffractionexperiment,wemustallowthateventhepropertiesofmacroscopicobjectscanexistinstatesofpotentiality.

True,thepotentialmomentaofthecrystalinthisexamplearealltoosmalltobemeasuredbythetechniquesofclassicalphysics,suchasmeasuringthevelocityofthecrystal;hence,thereisnopossibilityofshowingbysuchmeasurementsthatthecrystalhasanyoneofthesemomenta,muchlessseveral.Butthepracticalunobservabilityofmultiplicityinthisexampleisnotsignificantifouraimistosaywhat

goesonamongthematerialthingswhetherornotwelookatthem.

InSchroedinger'sthoughtexperimentwecaneasilydistinguishthepotentialstatesofthecat,buttheirallegedsimultaneouscontributioninpotentiacannotbedemonstratedbyaninterferencepattern.IntheDavisson/Germerexperimentwecanprovetheexistenceofthecrystal'spotentialmacroscopicstates,butahumanobservercannotdistinguishthem.Thetwoexperiments

complementeachother.Takingthemtogether,theconclusionseemsinescapable:Neitherindividualparticlesnormacroscopiccollectionsofthemareimmunetoquantalmultiplicityofanydegree.

Nevertheless,thatargumentprovesonlyasmalldegreeofmultiplicity.Perhapssomethinginthenatureofthingskeepstherangeofpotentialvaluessosmallastoescapedetectionbydirectmeasurement;hence,measuringinstrumentswouldalwayslookdefinite,evenwhentheyarenot.Thisthirdpossibleexplicationhasweaknessesofitsown.First,itstrainsoutamerelyquantitativegnatwhileswallowingthecamelofnonactuality.Ifanordinaryobjecthasdistinctpotentialvaluesofposition,momentum,andsoon,nomatterhownearlyequaltheymaybe,ithasnoactualvalueofthesecommonsensepropertieswhatsoever.Thatisaradicallydifferentclaimfromthecommonplacefactthatwecannevermeasuresuchapropertywithunlimitedprecision.Thisprincipleassertsthatthepropertyisnotactuallythere.Thecommonsenserealistaboutlaboratoryequipmentshouldnotacceptthat.Second,nomorecomfortcanbeextractedfromthisdefensethanthenewparentsgotfromobservingthattheirunplannedbabywasaverylittleone.Evenifamacroscopicobjectstartedoutwithrangesofpotentialmomentaandpositionsthatsatisfiedtheminimumallowedbytheuncertaintyprinciple,andifnofurtherpotentialvalueswereintroducedbyinteractionswithotherthings,thequantumtheoryshowsthattheeventualgrowthoftheobject'spotentialpositionswouldbelimitedonlybytheamountoftimeavailable.

Theprinciplemightberescuedbyaddingthatthereisalawatworkthatcutsoffthespreadingpotentialitiesastheyvergeonmacroscopicdistinguishability.Butthisattempttopatchuptherulelookssuspiciouslyadhoc.Thesemacroscopicpropertiesandtheirrangesarebuiltupofsumsofthecorrespondingpropertiesandrangesoftheparts.Theelaboration,then,amountstoanimposedlimitationonthe

potentialvaluesoftheparts.Butweknowthattheindividualpartscanhavepotentialvaluesthatspreadovermacroscopicranges.Withrespecttoposition,forexample,eachconductionelectroninapieceofmetalhasawavefunctionthatextendsfromendtoendofthewire.Sothelimitingprocessmustapplynottojustanymacroscopicallydistinguishablerangebutonlytothosecoordinatedpotentialvaluesofthe

partsthatwould,ifnotsuppressed,cooperatetomakeportionsofthewholeobject'srangediscriminablebyamacroscopicdetector.Noticethatthereisnoagentresponsibleforthispruningofpotentialities.Theparticlesmustexerciseself-restraint,withaneye,asitwere,ontheaudience.Ijudgethatthisproposalofamerelyapparentactualityinmacroscopicthingshaspassedoverthelinethatseparatesthebarelyplausiblefromtheexcessivelyadhoc.Butothersmayjudgedifferently;certainlysneeringatanideaisnotaseffectiveasrefutingit,andIhavenotrefutedthisone.

COULDitbethatanyinteractionbetweenaparticleandanyothermaterialthingtriggersthetransitiontoactuality?Suchaproposalcouldbeformulatedthus:

Rule4.

Whenevercircumstancespresentaparticlewitha"choice"amongalternativepotentialinteractionswithotherobjects,itwillactualizejustoneofthem.

Thisconjectureappealsstronglytocommonsenseintuitionsaboutpotentiality.Infact,itscarcelyamountstoanadditiontothecontingentlawsofquantummechanics,beingasimpleunpackingofthecommonsensemeaningofpotentiality.Thepossibilitiesofordinaryindeterminism,whatIhavecalledR-possibilities,looktowardanopenfuture;butwhentheopportunitypresentsitself,thefreeagentmustmakeitschoice.Theresultisthenengravedinthehistorybooks.Despiteitsappeal,wemaydismissthiscandidateimmediately,fortheexperimentofDavissonandGermercontradictsit,too.Anelectronoranatomofhelium,facingpotentialinteractionswithamyriadofscatteringcentersinacrystal,interactsactuallywithnosinglelatticepointbutscatterspotentially(inthesenseofQ-possibility)fromeach.

Yetinteractingwithadetectordiffersinonesuggestiverespectfromscatteringbyacrystal.Acollisionwiththelooselyboundconductionelectronsinaphotosensitivesurfaceoccursinelasticallyandirreversibly.Theincomingparticletransfersanappreciableamountofenergytoanelectronresidingoriginallyinthetarget,andtherepeatedtrialsofthiseventdonotbelongtothesameC-possibleworld.Instead,theymakeupastatisticalensembleofthesorttreatedinthermodynamics.AsLeonN.CooperandDeborahVanVechten(1969)pointout,onlyinsta-

tisticallyirreversibleprocessesdoestheobjectimpressonthemeasuringdeviceapermanentrecordofitspresence;consequently,thermodynamicirreversibilitymustcharacterizeanyinstrumentthatmightbeusedformeasuring.Thispointissignificantbecause,astheseauthorsalsopointout,thescatteringinterferenceexperimentsoccurreversibly,andtheseexperimentsgenerateourchiefevidencethatcontrarypossibilitiescoexistintheobjectsthemselves.Letustakeacloserlookatthistypeofexperiment.

Thecommonelementinthedesignofinterferenceexperimentsisthis:TheexperimentalapparatusmustpossesstwoormoredistinctQ-possiblehistorieswhicharemadetoconvergeonasingleoutcome.Andtheevidenceisnegative:Itconsistsofthenonoccurrenceofacommonresultwhichwouldhappenifthehistoriesweretracedoutsingly.Inordertoovercomethenormalinconclusivenessofnegativeevidence,theexperimentermustconstructamultitudeofreplicasoftheexperimentandshowthattheresultismissingfromtheentireset.Forexample,alargenumberofparticles,eachwiththesamewell-definedenergy,aresentthroughthedouble-slitapparatusoneaftertheother;andtheirnumberismadesolargethatthefrequencywithwhicheachQ-possibleresultturnsupmaybetakenasareliableindicationofitsprobability.Hence,theabsenceofrecordedelectronsatacertainplaceinthecompletedinterferencepattern,formedbymillionsthatdoarriveatotherplaces,teststhequantum-mechanicalpredictionthatalternativeC-possiblepathsconvergeandcancelatthatpoint.

Theevidentialvalueofaninterferenceexperimentderivesfromitsreplicability.Repeatedtrialscontributetoasingle,sufficientlywell-definedinterferencepatternjustbecausetheyreproducethesameC-possibleworldandthereforethesamesetofQ-possibilities.Becauseoftheessentialdesignofinterferenceexperiments,suchdirectevidenceofindefinitenesscanbeobtainedonlywithrespecttothose

portionsofanobject'sQ-possiblehistorieswhoseseparationcanbeundoneinthesamewayineachreplicaoftheexperiment.Consequently,weknowthatwewillneverbeconfrontedbydirectevidenceofindefinitenessinanyprocesscomplicatedenoughtoinvolveamultiplicityofC-possiblestates,asalwayshappensinthermodynamicirreversibility.Insuchconditions,nodistinguishableinterferencepat-

ternwillbefound,whetherornotatransitiontoactualitytakesplaceintheprocess.Theabsenceofapatterninirreversibleprocessescannotbecountedfororagainsteitheroftherivalconjectures.Insuredagainstdirectcontradiction,then,letusproposeanotherrule.

Rule5.

Theparticipantsinaninteractionactualizetheirrelevantpropertiesjustincasetheinteractionproceedsirreversibly.

Thisruleofferstwoadvantages:Itcannotbeprovedwronginaninterferenceexperiment,anditfocusesonjustthefeatureofmacroscopicobjectsthatmakesthememployableasmeasuringinstruments.Theunfalsifiabilityofrule5assuresthatwecansafelyadoptHeisenberg'sconjectureasaconventionalprescriptionforchoosingthepointatwhichweinsertfreshinformationabouttheresultofameasurement.ButifHeisenberg'sconjectureistoservehispurpose,anyrulewemayofferinsupportofitmustfunctionasmorethanaheuristicdevice;wemustbeabletotreatitasahypothesisabouttheworldofobjects.Buthowcanweevaluateanexperimentallyunfalsifiablehypothesis?Becauseatestliesbeyondourreach,wemustrelyonotherconsiderations,ofwhichlogicalconsistencyisthemostimportant.Letusinquirewhetherrule5fitslogicallyintotherestofourattempttointerpretquantummechanicsobjectively.Weshallfindthatitdoesnot.

Thedifficultystemsfromtherule'sreferencetoirreversibility.Statisticalthermodynamicssaysthatanirreversibleprocesstakesasystemfromastateoflowertooneofhigherprobability.Therelativeprobabilityoftheinitialandfinalstatesmaybeviewedfromtwoperspectives:fromtheoutside,withregardtotheexperimentalconditionsrequiredtosettheprocessinmotionortoreverseit;andfromtheinside,withregardtotheinnerworkingsofthesystem'sparts.Fromanexternalvantagepointwecharacterizeanirreversible

processbycontrastingtherelativesimplicityoftheapparatusbywhichthepartsaresetinmotionwiththecomplexityindeed,thepracticalunattainabilityoftheapparatusrequiredtoreversetheirmotionswhentheyhaveattainedthefinalstate.Referringtothesimplicityorcomplexityoftheapparatusbywhichwemanipulatetheexperimentfocusesattentionawayfromtheatomicobjectsandtowardtheexperimenter'slimitedknowledgeofandcontroloveratomicevents.

Internallydescribed,theprobabilityofastateisameasureofthenumberofdistinctpatternsofmotionofthemicroscopicparts(thenumberofdistinctmicrostates)thatwegrouptogetherunderasinglemacroscopic,andthereforepartial,description.Theinternalperspectiveisequallysubjective,becauseitconnectstheprobabilityofastatetothedegreeofdetailwebuildintoourdescriptionofit.Fromeitherperspective,then,theconceptofprobabilityisusedsubjectivelyinthermodynamics,inpreciselythesensefromwhichHeisenberg'spotentialismisdesignedtoprotectthequantumtheory.

Heisenberg(1958)commentsonacertainlackofobjectivityinthisproposedrule.

Atthispointquantumtheoryisintrinsicallyconnectedwiththermodynamicsinsofaraseveryactofobservationisbyitsverynatureanirreversibleprocess....Theirreversibilityis...aconsequenceoftheobserver'sincompleteknowledgeofthesystemandinsofarnotcompletely''objective.''[Pp.137,138]

Thethermodynamicdistinctionbetweeenreversibleandirreversibleprocessesmakesessentialuseofthenotionofstatisticalassemblies."If[one]triestocallasystem'sbelongingtoanassembly'completelyobjective'[one]usestheword'objective'inadifferentsensefromthatofclassicalphysics"(p.138).

BecauseHeisenbergexplicitlydisavowsaninterpretationof"observer"thatwouldlimitthetermtoconsciousbeings,wemustinterpret"incompleteknowledge"asaninabilitytodiscriminatebetweenmicroscopicallydistinctstatesofthemeasuredsystem,thatis,asatendencyforthe"observer"torespondinasinglewaytoagroupofdistinctmicrostatesoftheobjectsystem.AndyetHeisenbergsaysthateventhismetaphysicallyparsimoniousaccountofthetransitiontoactualityisnotcompletely"objective."Whydoeshe

makethisadmission?Hedoessobecause,insayingthatgroups("statisticalassemblies")ofdistinctpotentialprocessesleadtothesameresult,wefocusonaselectedportionofthecausalconsequencesoftheinteraction,namely,theglowingofalamportheswingingofagalvanometerneedle,ignoringvariousmicroscopicdistinctionsthatstillobtainintheobjectsthemselves.Ineffect,wesaythatnothingsignificantdistinguishestheresultingstatesofthesystem-plus-appa-

ratus,nothingnoticeabletoafurtherobserverofthatsystem.Thus,animplicitreferenceto"knowledge"remainsinthestory.Thatisthesenseanimportantone,IsubmitinwhichHeisenbergsaysthatthestoryisnotcompletelyobjective.

Thecriticismmaybeputcrudelythus:Ononeoccasionanelectroninteractspotentiallywithagroupofatomsarrangedtoformanarrayofphotomultipliers,initiatinginthosedevicespotentialprocessesofwhichlargegroupsresultinthesameoutcome,suchasthelightingofacertainlamp,andotherlargegroupsresultinthelightingofanotherlamp,andsoon.Onanotheroccasiontheelectroninteractswithagroupofatomsarrangedinacrystallattice,initiatingpotentialprocessesinthelatticethatcannotbesortedintogroupsaccordingtodistinctmacroscopicoutcomes.Theinteractionsinthesetwocasesaredistinguishedbytheiroutcomesinthelarge,many-atomsystemwithwhichtheelectroninteracts.Butthequestionofwhethertheelectrondoesordoesnotreduceitsrangeofpotentialitiesinaninteractionoughttobesettledbywhatisgoingonthereandthen,notbywhatwillhappenonsomefutureoccasion.Whyshouldthenaturesofthetwooutcomesmattertotheelectronsostronglyastoinduceittoactualizejustoneofitspotentialinteractionswhenitfacesseveralphotomultipliers,andtoretainthemallwhenitfacestheprospectofbeingscatteredbytheatomsinacrystal?Theconjecturethatthenatureofthepotentialoutcomeofaninteractioninducesthetransitiontoactualitylooksstrangelylikecreditingpresciencetotheparticle.

AruleofadifferentsorthasbeenproposedbyRichardSchlegel(1980,pp.212,213).Hecastshisprincipleintheformofalimitationonthesortofsuperpositionsthatmayoccurinnature.Schlegelintroducesthenotionofthe"modifiedgeneralLorentzgroup"oftransformations,definedas"thestandardvelocitytransformation,spatialtranslationandrotation,spacebutnottimeinversion,andchargeconjugation."Theoperationsofthisgrouprepresentthe

symmetriesinherentinthebasicinteractionsofphysics.Schlegelnotes,asa"generalizationfromexperience,''thatthevariousQ-possiblestatesofaparticle,itssuperposedstates,arerelatedbymembersofthisgroup.Thusthevariouspotentialpositionsofaparticlecanbetransformedoneintoanotherbyspatialtranslation;andaparticle'svariouspotential

momentaareinterchangeablebyvelocitytransformations.Themultiplicityofaparticle'sstatesisachieved,Schlegelsuggests,bymeansofthetransformationsofthemodifiedgeneralLorentzgroup.The"restrictedsuperpositionhypothesis,"then,canbeformulatedthus:

Rule6.

"Theonlystateswhichcanenterintoasuperpositionarethosewhichcanbereached,onefromtheother,bytheoperations[ofthemodifiedgeneralLorentzgroup]"(p.212).

Considertwosuccessesofthishypothesis.First,itdoesnotforbidmacroscopicthingstoexistinstatesofsuperimposedpotentiality.Forexample,itaccommodatesthesuperpositionofmomentumstatesthatwemustassigntotherecoilingcrystalintheDavisson/Germerexperiment;thesestatescanbetransformedonetoanotherjustasthesuperposedmomentaofasingleparticlecan.Second,iftheprincipalisappliedtocompositesystemsaswholes,itforbidssuperpositionsofmacroscopicallydistinguishablestates.Ablackenedgrainatonepointinaphotographicplatecannotbeconvertedintoablackenedgrainelsewherebydisplacingtheplate,orrotatingit,orbyanycombinationofoperationsappliedtotheplateasaunit.Theconversioncanbemadebutonly"inahighlyderivativemanner";thatis,onlybyapplyingthetransformationsseparatelytotheindividualparticlesthatcomposethesystem(Schlegel1980,p.213).

Despitethesesuccesses,thehypothesisfailstoaccommodatesuperpositionsthatweknowtobepresentinmany-particlesystems,forexample,inEPRexperiments.Considerasystemthatseparatesintotwoequalpartswhileconservingenergyandlinearmomentum.Letitbeasodiumdimer,say,initiallyhavingzerototalmomentuminsomeinertialreferenceframeandanindefiniteposition.Letitstartoutinanantibondingstatewhoseenergyisnotsharplydefined,in

accordancewithalifetimeT.Later,atatimelessthanT,thesystem'sQ-possiblestatesinclude(1)thestillintactdimer,(2)apairofsodiumatomsmovingwithequalandoppositemomentaofacertainmagnitude,(3)thesamepairmovingwithequalandoppositemomentaofadifferentmagnitude.Thesethreearetypicalofthemembersofthesuperposition.NotransformationofthemodifiedgeneralLorentzgroupnoranycombinationofthem,appliedtothewholesys-

tem,cantransformoneofthesestatesintoanother.However,althoughasingletransformationtoamovingreferenceframecanconnecttheundissociateddimeratresttotherestframeofoneoftheseparatedatoms,adifferenttransformationisneededtoreachtheframeoftheother.Yetanotherconnectstherestframeofoneoftheseparatedatomsinstate2totherestframeofthesameatomin3;butadifferenttransformationisrequiredtoconnectthesuperposedstatesoftheotheratom,becauseitismovingintheoppositedirection.Ifitistoworkinthisexperiment,therestrictedsuperpositionhypothesismustbeappliedonlyparticlebyparticle.Butthatreadingofthehypothesiswillnotsolvethemeasurementconundrum.Suchaninterpretationwouldnotforbidthephotographicplateinthedouble-slitexperimenttoexistinsuperposedstates.And,becauseeachparticle'spotentialstateinthedeadcatisrelatedtoitsstateinthelivingonebyacombinationofmembersofthemodifiedgeneralLorentzgroupadifferentcombinationforeachparticleSchroedinger'scatisallowedtoretainitsseveraldegreesofhealth.

Finally,supposethatthequantumsystemadoptsanarrowerrangeofpotentialitiesunderavarietyofcircumstancesbutthatnospecifiablecommonfactorinthemdeterminesthatitmustdoso.ThatistheconjectureproposedbyNancyCartwright(1983).Itisquestionablewhetherthisproposalshouldbecalledarule,butIshalldosoanywayandformulateitinCartwright'sownwords:

Rule7.

"Thereneedbenogeneralcharacteristictrueofsituationsinwhichtheevolutionisdeterministic[i.e.,nolossofpotentialities]andfalsewhentheevolutionisindeterministic[thewavepacketisreduced]"(Cartwright1983,p.201).

InsupportofthisproposalCartwrightassertsthatwehavemanyexamplesofexperimentalsituations,inadditiontomeasurements,

wherethewavepacketisreduced.Thus,

VonNeumanclaimedthatreductionofthewavepacketoccurswhenameasurementismade.Butitalsooccurswhenaquantumsystemispreparedinaneigenstate,whenoneparticlescattersfromanother,whenaradioactivenucleusdisintegrates,andinalargenumberofothertransitionprocessesaswell....Thereisnothing

peculiaraboutmeasurement,andthenthereisnospecialroleforconsciousnessinquantummechanics.[1983,p.195]

TheplausibilityofCartwright'sproposaldependsonwhetherthisassertioniscorrect.Letustestit.Dowehavereasontobelievethatpotentialitiesareerasedinapparatusesthatpreparebeamsofparticlesineigenstates?Consideronethatpreparesatomsineigenstatesofangularmomentum,suchastheStern/Gerlachexperiment.(PreparationsofthissorthavebeendiscussedinWigner1963,p.159,andinFeynman,Leighton,andSands1965,pp.59.)Atypicalapparatusseparatesexcited,metastableheliumatoms,whichhavethreepotentialorientationsoftotalzcomponentofspin,plus,zero,andminus.Theseatomspassthrougharegionofnonuniformmagneticfield,emergingonthefarsideinthreebeams,oneforeachofthethreeeigenvaluesoftotalspincomponent.Cartwrightseemstoclaimthateachatom,originallyowningallthreepotentialvalues,haschosenjustoneofthembythetimeitreachesthefarsideofthemagnet.Unlikethedouble-slitexperiment,inwhicheachindividualparticlepassesthroughtheapparatuspotentiallyineverypossiblepath,inanexperimentthatemitsbeamsofdistincteigenstates,eachparticlepassesdefinitelyalongjustoneofthethreepossiblepaths.

AsWigner'sandFeynman'sdiscussionsshow,orthodoxquantumtheorydoesnotcondonethisstory.Inprinciple,anexperimentcouldshowwhichaccountiscorrect.Thepreparationexperimentcanbemodifiedbysendingintoitabeamofparticlesallofwhichareinaneigenstateforadifferentorientationofmagneticfield,andhenceinawell-definedsuperpositionofthethreeeigenstatesfortheorientationofthismagnet.Themagnetthenproducesthreedistinctbeams.Beyonditanotherdevicebringstheseparatedbeamsbacktogether.Finally,asecondStern/Gerlachseparator,orientedalongthedirectionoftheoriginal,incomingeigenstate,teststheconditionofthe

particles.Iftheatomsundergoatransitiontoadefiniteeigenstateinthefirstseparator,thentheywillconstituteamixtureofeigenstatesintherecombinedbeam;thatis,somewillbeinoneeigenstateoforientationtotheseparatingmagnet'sfieldandsomeinanother.Nonewillhavethedefiniteorientationithadasitenteredthe

apparatus.Withrespecttothataxisoforientationeachwillnowbeinasuperposition.

However,accordingtotheorthodoxtheorythereconstitutedbeamisrestoredtoitsoriginaleigenstate.Thisresultmeansthateachindividualparticlepassespotentiallythrougheachbeam,interferingwithitselfintheregionofreunion,wheretheinterferencereconstitutesitsoriginaleigenstate.Anapparatusthatpreparesbeamsofdistincteigenstatesdoesnotsendoneparticledefinitelyintoonebeamandanotherdefinitelyintoanother;eachparticlegoespotentiallyintoeverybeam.Orsosaystheorthodoxtheory.Intuitionsdifferastowhetheritcanbetrustedtothisextent.Whatwouldhappeniftheexperimentwereperformed?Wignersays,"Thereislittledoubtthatinthiscasetheorthodoxtheoryiscorrect"(1963,p.161).Cartwright,ontheotherhand,entertainsalargedoubt.

WhatcanwelearnaboutCartwright'sconjecturefromactualexperiments?Partofherclaimconcernsanapparatusthatproducesnonoverlappingbeamsofparticlesindistincteigenstates.Onewell-knownopticaldeviceprovidestheevidenceweseek.(Experimentswithphotons,thoughperhapslesssatisfyingthanthosedoneonnon-zero-massparticles,areofteneasiertoperform.)Thepolarizationbeamsplitter,avariantoftheNicholprism,acceptsphotonsinaninputbeamandsortsthemintotwomutuallyperpendicularoutputbeamsinsuchawaythatthephotonsinonehaveahorizontallinearpolarizationandthoseintheotherarepolarizedvertically.ThisdevicedoesforphotonswhattheStern/Gerlachmagnetdoesforspin-one-halfparticles.Theoutputbeamscouldbesentseparatelyintootherexperiments,intheinterpretationofwhichonewouldnormallytreateachbeamasdeliveringparticlesinawell-definedstate,notmerelycomponentsofasuperposition.Butdotheparticlesreallyenterdefinitestatesastheypassthroughthebeamsplitter?WecanfindoutbypursuingananalogytotheexperimentdiscussedbyWignerand

Feynman.

Lettheinputphotonsbepreparedinaneigenstateoflinearpolarizationalongalineorientedatforty-fivedegreestothevertical.Eachphotoninthisbeamhasanequalchanceofemerginginthehorizontallyortheverticallypolarizedoutputbeams,havingmadeatransitionfromitsoriginalstate.Mirrorsplacedinthepathsoftheemergingphotonbeamsmakethemconverge

atsomedistantpoint.Whenwetestthereunitedbeamwithapolarizationanalyzer,wefindnotamixtureoftwokindsofparticles,halfinoneeigenstateoftheseparatorandhalfintheother,butjustonekind:Allthephotonshavetheeigenvaluethattheycarriedintothebeamsplitter.

Wigner'sconfidenceisvindicated,atleastforphotons.Eachparticlesamplesbothbeams.Therefore,contrarytoCartwright'sconjecture,theindividualphotonsdonotadoptexclusivelyoneortheotherofthetwoeigenstatesofferedtothem.Hereisanapparatusthatpreparesparticlesindistincteigenstates,yetfailstoreducethewavefunction.

Cartwrightalsorejectstheorthodoxinterpretationofscattering:

Aparticlewithafixeddirectionandafixedenergybombardsatargetandisscattered....Wemaycirclethetargetwitharingofdetectors.[But]evenwithoutthedetectors,theparticlemustbetravellingonewayoranotherfarfromthetarget.[1983,p.194]

Well,thatsuppositionappealsverystronglytoourclassicalintuition,buttheDavisson/Germerexperimentrefutesit.Anindividualparticleretainsitsmanifoldpotentialpositionsandmomentaafterscatteringpotentiallyfromeachatominanarrayoftargetsinacrystal.Onlyaspontaneousreductionaftertheparticlescatters,whileitisinflighttowardthedetectors,couldsaveCartwright'sassertionthattheparticlehasadefinitetrajectory"farfromthetarget."Perhapsparticlesspontaneouslyshedtheirpotentialitieswhileinsoloflightbetweencollisionsthemoreprobablythelongertheflight.Thishypothesis,too,couldbetested;itimpliesthattheinterferencepatternwouldgraduallybewashedoutasthedistancebetweenthedetectorsandthescatteringcrystalincreases.Certainitis,however,thatorthodoxquantumtheorydoesnotaccommodatethissortofspontaneousreduction;neither,sofar,doesexperiment.

Theconjecturethatradioactivedecayproducesparticleswithdefinitetrajectorieswouldbehardertotest.Theparticlesemergingfromthebetadecayofacollectionofnucleicouldinprinciplebeallowedtoenteradouble-slitapparatus.Accordingtotheorthodoxtheory,eachbetaparticlepassespotentiallythrougheachslit,interferingwithitselfintheplaneofthedetectorsbe-

yond.Aninterferencepattern,however,willnotbebuiltupbytheseparticlesbecausetheindividualnucleidonotemittheirelectronsinphase;hence,themaximumsandminimumsofoneparticle'sprobabilitydistributiondonotcoincidewiththoseofanother.

Cartwrightproposesthattheorthodoxtheorymustbemodifiedtoaccommodatetheseallegedcasesofspontaneousreductionofthewavepacket.Ifsuchreductionsindeedoccur,thenwedonotneedthehypothesisthatconsciousnessplaysaspecialpartinquantumphenomena.ButwehavenoevidencetosupportCartwright'sconjectureandmuchthatweighsagainstit.

Noneofthesesevenattemptstomakesenseofthetransitiontoactualityaccomplisheswhatwedemandofit.Isubmitthat,ifweinsistonspeakingonlyaboutmaterialparticles,anyattempttointerpretquantummechanicsrealisticallywillfail.However,wecouldcontinuetospeakoftheeventsinthelaboratorynextdoorasiftheyrunonwithouthelpfromourselves,providedthatweaddtoourinventoryofitscontentsanothercausalagentthatisnotaparticleoragroupofthem,namely,themindoftheinvestigatorwholaborsthere.

Personswhoareunwillingtoabandonthephysicalisttheoryofmindwillfindsuchaproposalunacceptable.Butthosewhoalreadysuspectthephysicalistprogramcouldfindaplaceforminds,forindoingsotheywouldmerelybegrantingemploymenttoanacknowledgedapplicant.Asaninducementtotheformergroup,Ihaveofferedinchapter8anargumentfordualismthatflowsnaturallyfromthecentralthemeoftheseessays,namely,thetensionbetweenunityandpluralitythatstrainsevenaNewtonianworldview.ButtheNewtonianandquantum-mechanicalargumentsstandorfallindependently.Bothsupportametaphysicalconclusionsowidelydoubtedasalmosttorequireparallelandindependentbuttressing.Letusexaminemorecloselytheimplicationsoftheproposalthatmindseffectthetransition

toactuality.Indeed,shortofabandoningrealism,weseemtohavenoalternative.

TheMindHypothesis

Whyareactualizationsassociatedwithpotentialinteractionsinaphotomultiplierandnotwiththoseinacrystallattice?

Nothingthatappearsatallrelevanttoourconcernsdistinguishestheeventsastotheirobjective,intrinsicproperties,butthereisoneobviousdifferenceintheircausalconsequences:Becauseofthewaytheapparatusisarranged,potentialcollisionsindistinctparticledetectorsleadtoexperientiallydistinctpotentialbrainstatesinthegraduatestudentwhoisconductingtheexperiment,whereaspotentialcollisionswithdistinctatomsofthecrystalarenotsocoupledtoanobserver'scentralnervoussystem.Shouldwethenconcludethatcorticalneuronspossessinthemselvesthepowertocompeltransitionsfromthepossibletotheactual?No,wehaveshakenoffessentiallythesameerrorinconnectionwithrules2,3,and4.Neuronscontainthesameatomicparticlesasarefoundincrystallatticesandphotomultipliers,andtheircausalconnectionswithotherpiecesofmatterproceedbymeansofthesametypesofinteraction.

Quantummechanics,relentlesslyapplied,indicatesthatinteractionsamongmaterialobjectsspreadpotentialitymoreandmorewidely.Nowpotentialityhasbeeninterpretedonlypartiallyandindirectly,merelyasatendencytogenerateexperiences,usuallyincompatibleones.Itis,ofcourse,muchmorethanthis,forthemultipleactivitythatunderliesitgoesonwhethermindsareconnectedtoitornot.Nevertheless,itispropertoinquireastowhenthesetendenciesgetrealized.Towardwhatdefiniteresultdoesanindefinitesystemtend?

TheanswerproposedconjecturallybyJohnvonNeumanandbyWigneristhis:Abrain,sharingthemultiplicityofalargersystemtowhichitiscoupledbymeansofsensoryorgansandmeasuringinstruments,tendstoproduceadefinitestateinametaphysicallydistinctkindofentitybymeansofanotherkindofinteraction,onethatjoinsthematerialandthementalorders.TakingSchroedinger'sconjectureseriously,weconcludethatquantummechanicsspeaksthetruthinallofitsassignmentsofpotentialitytomaterialobjects,uptoandincludingtheneuronsinabrain,beingcurtailedonlyatthepoint

whereitinducesamindtoundergoanactualexperience.Thisisactualityinitsprimarysense.Andthemindreactsupontheparticles.Inthattransactionbetweenontologicalcategories,andonlythere,dosomeofthecorrelatedpotentialitiesofcerebralcortex,retina,photomultiplier,andscatteredelectronvanishfromtheobjectiveworld,leavingamuchreducedset.

Thisconditionisoftencalledactualityamongtheparticles.Thedefinitenessachievedhereis,ofcourse,limitedtothesetofpropertiesinvolvedinthechainofcausesthatconnectsthetravelingelectrontothecerebralcortex.Intheplaneofthedetectorstheparticleacquiresamorenearlydefinitepositionbutnotadefinitemomentum,becausethoseinstrumentshavebeenconnectedtotheobserver'ssenseorgansinsuchawaythatdistinctpositions,butnotdistinctmomenta,leadtodistinctsubjectiveexperiences.

Admittedly,Schroedinger'sconjectureseemsimpossiblyfanciful.Instinctive,naiverealismleadsusalmostirresistiblytotreatourexperiencesoftheworldasutterlytransparent,asplacingusindirectcontactwiththeperceivedthing.Wepayattentiontotheblockofstone,nottotheeyesandfingertipsthroughwhichweexperienceit.Onlybyphilosophicaleffortareweabletodistinguishtheexperiencefromitsobject.

Experienceneversuperimposesincompatibles.Justso,nomaterialthingbigenoughtobeseenorfeltorheardhaseverbeenexperiencedinincompatiblestates.Aswithourbodies,sowithourtools;weprojectourexperiencesouttotheverytipofthemeasuringinstrumentthatmediatesthem.Nocellviewedthroughamicroscope,noparticlelocatedbyadetector,isever"seen"inincompatiblestates.Onlywithdifficulty,keepinginmindtheuncompromisingresultsofinterferenceexperimentsaswellasthemoresubtleindicationsofquantummechanics,canweavoidtheerroneousgeneralizationthatthoseobjectsareinherentlyasdefiniteastheexperiences.And,providedwerestrictthegeneralizationtothermodynamicallycomplexsystems,wecankeepupthepretense.Justastheartistleaveshisbrushesinthestudiowhenthepaintinggoestothegallery,soweexcludetheexperimenter'sretinaandphotomultipliersfromthescientificpictureoftheobjectiveworld.Indeed,wegainaconsiderableconvenienceinexpositionifweyieldtoourinnateproclivitytothinkoftheactof

observingasmerelyrevealingtoourreceptivemindstheresultsofpreviouslycompletedtransitionstoactuality.Nopracticalharmresults,either,providedonlythatwedonotattributeactualitymorelavishlythanthesubjectiveexperiencewarrantsustodo.

Becausewecannevercontrolthemicroscopicparametersofameasuringinstrumentsominutelythatrepeatedtrialsofanex-

perimentcouldgenerateaninterferencepatternfortheinstrumentitself,Heisenberg'sconjecturethatmeasuringdevicesprickthebubbleofpotentialitycannoteveninprincipleleadustoerrinpredictingobservations.ThedisagreementbetweenhisandSchroedinger'sconjecture,therefore,carriesnomeaningwhateverinthecontextofaninstrumentalistviewofscience.Ifexperiencesareallwecaneverknoworcareabout,thenthepreciselocusofthetransitiontoactualitymattersnotawhit.ButHeisenbergisconcernedtomaintaintherealistdoctrinethataknowingsubjectmakescontactwithobjectsthatareotherthanselfandthatourbestphysicaltheoriesrevealsomethingofwhatgoesonintheobjectiveworld.Consequently,thepracticalindistinguishabilityofhisandSchroedinger'sdivergentconjecturesdoesnotdiminishtheirphilosophicalimportance.Wewanttoknowwhatentitiescomprisethefurnishingsoftheworld;andonecriterionofwhattoplaceonourinventoryistheconsistencyofthestorywecantellaboutthemachineryofnature.Wehaveseenthat,althoughHeisenberg'sconjecturesetsmindsofffromtheworldofmaterialobjects,itcommitsustoadistastefullyarbitrarytreatmentofmeasuringinstruments,whereasSchroedinger'sallowsustoplaceallmaterialthingsandtheirinteractionsunderthedynamicallawsofquantummechanics.Onthelatterview,allofthepartsofasystemshareinitspossibilities,andallparticipateinthetransitiontoactuality.OnlySchroedinger'sspeculationappliesquantummechanicsconsistentlytoallmaterialthingswithoutimplyingthepresenceofhiddenvariablesandwithoutintroducingarbitrarydistinctionsamongmacroscopicobjects.Totheextent,then,thatweareguidedbythecurrentstateofscientifictheory,weareimpelled,oratleastnudged,towardametaphysicaldualismofmatterandmind.

AlthoughdualismfitsnotatallcomfortablyintotheatomistprogramofDemocritusandLucretius,physicshasreacheditbyfollowingtheprogramfaithfullystepbystep,yieldingonlytothefactsthathave

turnedupalongtheway.Quantummechanicsmakesroom,asNewtoniandidnot,foranewkindofcausalaction,inadditiontomechanicalcausation.Byadmittingmindsastheagentsofactualizationwecanregardasmorethanmerelyillusoryourintuitionsaboutourselvesasunitarycausalagentswhosometimesintroducenoveltyintotheflowofevents.

Indeed,quantummechanicsseemstodeliverwhatCharles

SandersPeirceandWilliamJamescallforintheirattacksondeterminism.Writingbeforetheadventofquantummechanicsandtryingtofindroomfortheexerciseofhumanwillinthecourseofevents,Peircewantstoadmit''purespontaneity...asacharacteroftheuniverse''(1892,p.333).Headvocatesadoctrineofabsolutechancenotforitsownsakebutbecausechanceloosens"thebondofnecessity,"thusmaking"roomforanotherkindofcausation,suchasseemstobeoperativeinthemind"(p.334).Peirceiscontenttopostulateaseverelylimitedindeterminism,onethatlurkswithinthegapsleftinthescientificworldpicturebytheinescapableimperfectionsofscientificinstruments(p.329).DaringmorethanPeirce,James(1897)anticipatesalmostexactlytheflavorofthepotentialistinterpretationofquantummechanicsasheattemptstosupport"ourordinaryunsophisticatedviewofthings.""Tothatview,"hesays,"actualitiesseemtofloatinawiderseaofpossibilitiesfromoutofwhichtheyarechosen;andsomewhere...suchpossibilitiesexistandformapartoftruth"(p.150).LikePeirce,Jamestakesaninterestinchancebecauseofthespaceitclearsforvolition.Humanchoosings,hesays,seemtohave"thestrangeandintensefunctionofgrantingconsenttoonepossibilityandwithholdingitfromanother,totransformanequivocalanddoublefutureintoaninalterableandsimplepast"(p.158).

Quantummechanicssetsalimittotheprogramofatomisticreductionandprovidesanimportantsupplementtoitsmodelofcausalagency.Itdoessobyforbiddingthereductionofconsciousnessandbyassigningapeculiartasktominds.Inoneinteraction,materialobjectsinduceamindtoundergoastateofconsciousnessandthemindreactsuponthematerialsystem,causingtransitionstoactuality.Inthisnewtypeofcausalprocessliesthepossibilityofanewreplytomechanisticreductionism,onethatisforbiddenbyNewtoniandeterminismandisunimaginableinthecontextevenofPeirce'sindeterminism.Quantum

mechanicsdoesnotdictatethedetailsofthisreply,butalittlecautiousspeculationmaypermitustoguessitsgeneraltrend.

Asacautionarytransitiontothenextchapter,letmeemphasizethatthesuccessofquantummechanicspermitsusindeed,somefeelthatitencouragesustoadoptaninstrumentalistviewofscientifictheorizing,groundedonanidealistmetaphysics.Schroedingerhasdemonstratedthisinoneofhislateressays

(1956).Ifthatisourchoice,however,thenquantummechanicsfunctionsmerelyasacalculatingdeviceforrelatingonesetofexperiencestoanother,andthereourinvestigationmustend;wecanasknofurtherquestionsaboutthenatureofthings.Butifwepersistinapplyingthecategoriesofactualityandpotentialitytotheworldofobjects,thenwecanaskandanswerfurtherquestions.Suchactivityispreferabletosilence,eventhoughtheanswerswebreatheoutmayseemtohavebeeninhaledfromapipe.Readingquantummechanicsrealistically,asthecorrectandfundamentalstoryaboutthewaythingsare,wefinditpossibletomakesomeprogresstowardapictureofthegeneralschemeofthings.Inevitably,thepicturewillhaveregionsofobscurity,evenblankspaces,butwecanalsohopeforareasofclarity,fantasticthoughtheymayseem.Letusmaketheattempt.

ElevenNotesforaQuantalWorldPicture

Introduction

Letmenotraisefalseexpectations:Ishallnotquellthemajorobjectiontomatter-minddualism.Myaiminthisconcludingchapterismoremodest.Whileacknowledgingtheproblemsofdualismandthemisgivingsitarouses,Iwanttorecommendthephilosophicalchallengesitlaysbeforeus.Theobjectionisserious,butIsubmitthatnoneofouralternativesisproblem-free;hence,wecanonlychoosetoreplaceonecomplexofpuzzlesandembarrassmentsbyanother.Wecan,however,trytochoosewisely.IftheargumentsofthethreeprecedingchapterscarrytheloadIhaveplacedonthem,anatomisticmaterialismisuntenable.AndIhavesetitsnonrealistalternativesoutsidetherangeoftheseessays,fortworeasons.First,idealismsandphenomenalismscannotdojusticetoourstrongsenseofbeingacteduponbyexternal,independentlyexistingagents.Second,theyfailtoprovidetheimpetusforfurtherinquirythatwegetfromanattitudethatgrantsrealcausalagencytomolecular,atomic,

andsubatomicparticles.Onlymicrophysicalrealism,orsomethingpracticallyindistinguishablefromit,namely,awillingnesstoactasiftheinvisibleparticlesarereallydoingthingsoutthere,couldhaveproducedmolecularbiology,structuralchemistry,andparticlephysics.Merelylookingformathematicalorverbalformulastocorrelateexperiences,Isubmit,wouldnotsustainorevenmakesenseoftheadvanceofmodernnaturalscience.Asguidesforinquiry,idealismsandphenomenalismsarestultifying.

Nevertheless,tomanythoughtfulpersonsthedualismIhaveendorsedwillseemintolerable.Whatremains,then?Justthis:tofindawaytotolerateit.Asaninitialefforttowardthatend,IshalltrytopeerashortwayaheadintotheterrainopenedtousbyaWestern,realisticinterpretationofthequantumtheory.Iwanttoshowthatthedualist'spositionismorethantolerableitiseveninteresting.Tosupportthatclaim,Ishallposesomequestionsofthesortthatcouldnotarisewithoutatleastacrypto-realistinterpretationofatomictheorybutthatmakesenseaspuzzleswithinarealisticdualism.Further,Ishalltrytoshowthatsomethinginterestingcomesfromthisspeculation;thatis,thatitleadstosomemoreorlessplausibleconjectures.

Dualism'smainobjectionablefeatureishighlightedbythesequestions:Howcouldmetaphysicallydistinctthingsanindividualmindandtheshiftingcoalitionofatomicparticlesthatconstitutesanindividualbrainachievetheintimacythatdualismassignstothem?Howcanweunderstandtheabilityofamindtobeacteduponbyonebrainratherthananother,andtoreactuponanevenlargercollectionofparticlesasitinducesthetransitiontoactuality?Theopacityofthispuzzleiswidelyfelt.HilaryPutnam(1979),quotingShimony,asks,"Byvirtueofwhatpropertiesthatitpossessesis'consciousness'abletoaffectNatureinthispeculiarway[reducingthewavefunction]?"andreplies,"Noanswerisforthcomingto[thisquestion]"(p.165).

Twosortsofresponsemaybeadoptedhere.Letusseewhethereithercanhelpus.

First,wecancallforpatienceandfurtherstudy.Thisplea,however,mustbesupportedbysomeindicationthatthepatiencewillberewarded,thatstudymightproducesomeplausibleandenlighteningstories.Ofcourse,furtherstudymightrefuteindeterminism.Itisconceivablethatpotentialismmayyetberooted

outofthequantumtheoryifexperimentalattemptstoshowthepresenceofhiddenvariablesfinallysucceed.Butthatoutcomedoesnotappearlikely.Ageneralontologicalprogramsuchasdualismwillprobablynotbeestablishedoroverthrownbyfurtherworkinthelaboratory.Rather,itmustrecommenditselfbybearingotherintellectualfruit.Oneofthehallmarksofapromisingparadigmisitsabilitytogeneratespecificpuzzlesinteresting,limitedquestionstowhichplausibleanswerscanbeproposed.Ifdualismleadsusonlyintoanembarrassedsilence,wewoulddowelltogiveitup.Butifitinspiresalineofinvestigation,evenmerelyofinterestingspeculation,thenitwillhaveearnedourseriousattention.

Thesecondkindofresponsehasgoodcredentialsbutmustbeusedextremelysparinglylestitloseitsforce.Undercertaincircumstanceswemaylegitimatelypointoutthat,inacontingentuniverse,noteveryfactgetsexplained.Thebasicfactsaboutthenatureofthingsaresimplythere.Werewetoadoptthisattitudetowardmatter-mindinteraction,wewouldsimplyadmitthemystery.Wehaveadmittedseveralothers,equallyopaquebutnowfamiliarandthereforealmostcomfortable,intotheworldpictureofmodernatomisticscience.Thebasiclawsofmechanicsmighthavebeenotherthanwhatwenowholdthemtobe.Aristotlemighthavebeenright;somightNewton;Einsteinmightbewrong.Whydoestheuniverserealizethesemechanicallawsratherthanothers?Whydoestheelectro-weakinteractiondisplaythefeaturesitdoesandnotothers?Whydoesthefinestructureconstanthavejustthatvalueandnotsomeother?Whydofundamentalparticlescomeinjustthesecategoriesratherthanothers?Mysteriessuchasthesewillnotbedissipatedwhentheoristssucceedinderivingsomeorallofthemfromdeeperprinciples;theaurawillsimplyfloatovertothoseprinciples.Despiteitsinnercoherenceandaustere,abstractbeauty,theuniverse,likeaworkofart,isultimatelyacontingentfact,whichistosayitisunexpectedand

unexpectable.

Byvirtueofwhatpropertydoesamindinteractwithasetofparticles?Well,onemightalsoaskforthepropertiesthatenabletwoelectronstoexchangevirtualphotons.Theanswer,electricalcharge,isnotanexplanationbutmerelyanameforthepropensity.Nowitmayturnoutthatthecollapsingofwavepacketsisnotafundamentalfactofmind-matterinteractions,inwhich

caseShimony'sandPutnam'squestionwillhaveaninterestinganswerintermsofwhateverturnsouttobefundamental.However,thiscollapseistheonlyindicationwegetfromquantummechanicsthatconsciousnesscantakeahandintheaffairsofordinarymatter;hence,itlooksverymuchlikethefundamentalfactabouttheirinteraction.Andtrulybasicpropensitiesdonotreceiveexplanations.Sowewillnotviolatetherulesofnaturalphilosophizingifwesimplybuildintoouraccountofthetransactionsbetweenmindsandparticlesthepropensityofamindtotriggerthe"transitiontoactuality."Justhowfarcanwecarrythisresponse?Howmuchcanlegitimatelybeconsignedtothecategoryofbasic,unexplained,contingentfact?Thisquestionmustremainopen.Itsanswermustawaittheresultsofattemptstosolvethespecificpuzzlesposedbyadualistic,quantalontology.

Certainly,wemustnotassemblearosterofultimatefactstoofreely.Inevitably,wewillbegintoregretthenumberofitemsonthelistandtodemandanexplanationintermsofphysicalorpossiblyevenmentalmechanisms.Theadhocisasundesirablehereasinexplanationsofparticleinteractions;hence,wemustviewwithsuspicioneachiteminourtentativecatalogoffundamentalfacts,askingwhethersomemaybeunderstandableintermsofothers.Butwecannotdowithoutthelist.Theuniverseiscontingent.Ishall,therefore,proposeapartiallistoffactsofcommonexperiencethatmayhavevalueasevidence.

Buildingontheseshredsofsometimesdubiousevidence,Ishallproposeapicture,plausiblethoughinevitablysketchy,ofonepossiblecombinationofontologyandepistemologythatisnotinconsistentwiththeinterpretationofquantummechanicsurgedaboveandmayevencastsomelightuponit.LetmeemphasizethatIdonotclaimthatthefragmentaryphilosophicalpositiontobeoutlinedhereisdictatedbyquantummechanics,althoughIthinkithasinformedthe

thinkingofsomequantummechaniciansfromthebeginning.Otherviews,radicallydifferent,mayalsobeconsistentwiththetheoryforexample,athoroughgoingidealism.Quantummechanicspermitsmuch.ButIshallnotsoaronnewlyunfetteredwingsoverthespeculativevistasopenedbythetheory.Rather,Ishallattempttopreserveasmuchaspossibleofaprequantal,realisticepistemology,onethat

respectsthedeepmoatthatmodernphysicsseemstodigbetweenappearanceandreality.

Asevidencethatthispartialworldpicturedeservesattention,Ishallconcludebydrawingfromitsomequestionsaboutspecificaspectsoftheinteractionbetweenmatterandmindandsomepuzzlesabouttheplaceofmindinthelargerschemeofthings.

BackgroundforSpeculation

KnownandKnowingThings.

Interpretingquantummechanicsrealisticallyhasledtoanontologyinwhichthecausalagentsbelongtotwodistinctordersofbeing:thematerial,whoseunitsaretheparticlesofphysics,andthemental,consistingofindividualminds.Amindisinducedtoperformtheactivitiesthatcountasexperiencesofthematerialworldasitinteractswiththeparticleswhoseexistencewepostulateintheoreticalphysics.Thoughtheyinteract,theseobjectsexistindependentlyofourselvesandofoneanother.Inthisassumptionweextendconjecturallytomaterialthingsthesameindependenceweknowbyintimateacquaintanceinourownactivityasinteractingbutindividualpersons.Weknowtheobjectsnotdirectlybutonlythroughtheireffectsonconsciousness.Thatisthecaseevenforcommonsenseobjects.WhatthekeyboardofmywordprocessorisinitselfIcannotsay;butIdoknowthatsomethingisgoingonouttherenowthatislikewhathasgoneonoftenbeforeandthatiscapableofgeneratingwhatIhavelearnedtocallkeyboardexperiences.Andthesomethingthatabides,nottheexperiencesthatcomeandgo,isthekeyboardtowhichIrefer.

Butthequantalconceptofpotentialitygivesadeepersignificancetothedistinctionbetweenthewaythingsareinthemselvesandthewaytheyappeartous.Thetheoryshowsthatourepistemicconnectiontotheobjectmust,ofphysicalnecessity,belimitedtoonlysomeofits

aspects.Theobjectissingularanddefiniteinanyaspectitpresentstoconsciousness,whereasitteemswithmultiplealternativesinmostofthefeaturesnotavailableforscrutiny.Wecannot,therefore,directlyexperiencethequantummultiplicityofexternalthingsandcan,indeed,conceiveofitonlyindirectly,asanabilitytoaffectourselvesinseveraldiverseways.Inwhat,then,doesamaterialsystem'sabilitytogeneratetwoor

morelogicallyincompatiblesenseexperiencesconsist?Wecannotsaymuchinanswertothatquestion.Atbestwecanmultiplythekindofstatementwemakeaboutordinary,definiteobjects:"Somethingisgoingonoutthere(theparticlesaredoingit)ofthesortthathasbeenpartlyresponsiblefortheexperiencesIhavelearnedtointerpretaslive-catexperiences,andtheparticlesarealsodoingsomethingofthesortthathasbeenpartlyresponsibleforwhatIhavelearnedtointerpretasdead-catexperiences."

Objectivity.

Thegrantingofindependentontologicalstandingtotheobjectsthatunderlieourexperiencesis,Isubmit,thecoreofthescientificattitudetowardnature.Objectivityisthefootholdwemustnotloseasweresisttheantirealisttugofthequantumtheory.

Theobjectiveattitudecanbeseenmoreclearlyincontrasttowhatmanypractitionersofthehumanitiesfindtobeasatisfactoryworkingrelationshipwithnature.AldousHuxley(1963)typifiesthisotherstanceinanessaythatmakesapowerfulcaseforquiteanothersortofreplytoreductionism.Huxley'sremedyforthecoldmechanismoftheatomistphilosophyisametaphysicsthatplacesMindatthecenterofthings.Huxleyattractivelypresentstheliterarysideoftheculturegap:Literatureinterpretshumanexperienceofallsorts,fromthenearlyineffabletothecompletelypublic(WilliamBlake,say,toAlexanderPope),by"purifyingthewordsofthetribe"togetpreciseyetmultiplemeanings.Literaturesubordinatesthingstoexperiences;itlooksatthingsalwaysandonlyinrelationtothehumanmind,onlyascontributorstohumanmeaning.Certainly,Huxleywouldmakeoneexceptiontothisrule.Otherpersonswouldnotbethussubordinatedtotheartist'sexperiences:Persons,andtheyalone,wouldbeaccordedatranscendentstatusasbeings-in-themselves.Respectforpersonsrequiresthatonenotviewthemmerelyinrelationtoone'sowninner

life.Indeed,Huxleydoesbrieflyadoptanevenbroaderobjectivitywhenheasks,

Howdidtheillimitableinanegetonwithouttheperceiving,feelingandthinkinginhabitantsofthisandalltheotherdarklittleworldsofwoe,bliss,loveandfrustrationnottomentionpoetryandscience?Andhowwillitgetonwhenweareallgone?[P.63]

Butotherwisehefocusesexclusivelyonexperienceshowtosortthemout,howtoexpressandenhancethem.Indeed,withregardtoinanimatethingsHuxleyseemstobelievethatscientists,too,donothingotherthanorganizehumanperceivingandthinking(leavingfeelingforotherstoexplore);thattheyinterpretexperiencesofthemostpublicsortbymeansofwordsstrippeddowntosinglemeaningsandofconceptswhosesolejustificationisthattheyserve"operationally"totieonesetofinnereventstoanotherinalogicalnetwork.

That,however,isnotatallwhatmostscientiststhinktheydo.Mostofthemarerealists.Isubmitthattheessentialspiritofscience,theattitudethatalonemakespossiblesuchanunprecedentedrelationbetweenhumankindandnatureisthis:consciouslyanddeliberatelytoapproachinanimatethingswiththesamehumility,thesamedelicatehesitationtoimposeone'sowninterpretativeschemeupontheother,thatweaccord(inourbettermoments)tootherpersons.Insciencethewordforthisattitudeis"objectivity";whenweadoptittowardotherpeoplewecallitrespect.Dealingobjectively,respectfully,withnature,scientistsattempttofocusnotontheirownexperiencesbutthroughthemtothethingsthemselves.Unabletoapproachnaturewithoutsomepresumptivesystemofconcepts,theyneverthelesstrytoemploythatsystemsotentativelyandwithsuchhumilityastogivenatureeverychanceofrefutingit.Thatistheexperimentalmethod:tomakenatureitselfanactivepartyinthedebateoverthenatureofthings.This,ofcourse,isnottosaythattheartist'sattitudetowardtheworld,whichisequallyrespectfulinitsownway,islessworthythanthescientist'sobjectivity;theartisthasnoblebutdifferentaims.Still,naturedoesnotthrustitsself-revelationsuponus.Thesculptor,whofocusescentrallyontheemergingfigureandonlyperipherallyonthestone,hearsonlypartofwhatthemarblewhisperstoamineralogist.

Howcanwereachouttotherealitybeyondexperience?Beginning

withtheGreekatomists,naturalphilosophyhasofferedoneway,thepathofhypotheticalreasoning,pavedwiththeconceptsoftheoreticalscience.ButHuxleydoesnotbelievethatconceptsofanysortcanhelpusbreakoutoftheclosedcircleofourordinaryperceptionshencehisoperationismwithregardtotheories.How,then,canwereachout?Herecommendsanotherpath,thewayofmysticalexperience.

Huxleyseemstoemployarestrictedsenseoftheterm"know,"accordingtowhichtheonlyrealknowledgeisself-knowledge;hence,theonlywaytoknowanotherthingistobecomeonewithit;hencetheimportanceofthemysticalemptyingofself.But,withoutdenigratingthissenseoftheterm,Isubmitthatwewouldblindourselvestoanimportantaspectofourconnectiontotheworldunlessweused"know"alsoinothersenses.Letusstipulatethatonecanalsohaveknowledgeaboutanotherpersonorthingknowledgemediatedbysensoryexperienceandconceptualinterpretation,fallible,usuallyonlyapproximate,oftenmixedwitherror,butknowledgenonetheless.Letusassumethepossibilityofobjectiveknowledge.

Imeanbythistermmorethanmerelyknowinghowtocopewithexternalobjects.Thatisyetathirdtypeofknowledge,thepractical.Butwecanalsohaveconceptual,theoreticalknowledgeofotherthings.Inwhatdoessuchknowledgeconsist?Itisamoredistantrelationthanunionwiththeobjectyetmoreintimatethanmerelyusingitforone'sownpurposesorrespondingtoitinsurvival-promotingways.Itconsists,rather,inputtingone'sselfintoakindoflimited,partialresonancewiththeobject,inadoptinganinternalstatethatreproducessomefeaturesofitsformalstructure.Thestructureisthenknownintheintimatesenseofbeingactivelyandconsciouslyembodied,andtheobjectisknownindirectlybythissharingofstructure.Thereisnothingmysticalaboutthiskindofknowledge.Thelawsofmechanics,forexample,reproduce,asmathematicalentities,somethingoftheformalstructureoftheactivitiesofthematerialobjects,andasthoselawsbecomeencodedinourbrainsweacquiretheoreticalknowledgeofthethingswhoseactivitiesarethusmimicked.1

Theconjecturethatknowerandknownbelongtometaphysicallydistinctcategoriesmayseemtoplacetoolargeadistancebetweenthem,asifthemindwerelockedawayinsidethecranium,compelled

toviewphantasmicfiguresprojectedbythecerebralcortex.Isuspectthatmuchoppositiontothetheory

1/RobertGreenler,forexample,intheprefacetoabookonatmosphericphenomena,expressesasenseofresonatingthuswiththeobjectofknowledge:"Thebeginningofmyinterestliesinmychildhoodaweofthebeautyoftherainbow.MyresponsetosomethingthatIlikeistotrytopersonalizeitbymyownparticipation.Tryingtounderstand[thesephenomena]isoneofmyformsofpersonalparticipation"(1980,p.ix).

stemsfromthisinterpretation;certainly,itwasthesourceofmyownreluctance.But,infact,dualismpreachesnosuchisolation.Evenordinaryperceivinginvolvesparticipationintheobjectofknowledge.Thefamiliaroccupantsofourperceptualworldthecreamycloudtwistingacrossanaquamarinesky,thepurpleirisstretchingupfromthemarginofashallowpool,thefragrant,grittystrawberryareallofthemproducedbyintimatecollaborationbetweenthemindandtheseveralsetsofparticlesthatundergirdthesky,flower,andberryexperiences.Insensoryperceptionthecollaborationgainsmorefromthecontributionofthemindthanfromtheformalcharacterofthematerialobject,thoughbothhelptoshapetheactivity;inscientific,rationalunderstandingthebalanceshiftstowardtheobject'sstructuring.Buttheknowerandthethingknowncontributecooperativelytotheexperienceinbothtypesofknowing.Thereoccursakindofunionbetweenknowerandexternalobject,amerginginacommoncreativeexercise.Thisisnotinitselfthat''onenesswiththeuniverse''ofwhichmysticsspeak;butIsurmisethatthedirectapprehensionofthismutualitycontributestothemysticalexperience.

Allthiscooperationnotwithstanding,inmaintainingobjectivitywesystematicallyeliminateourselves,theknowingsubjects,fromthestorywetellaboutthewaythingsare.Howfarcanthispracticebecarried?A.PeresandW.H.Zurek(1982)claimthatthescientificstorymusteventuallyrefertothestorytellerbecausequantummechanicsisessentiallyself-referential.Theysuggestthatthisfeatureofthetheoryexplainswhywemustdrawthatstrangelyelasticlinebetweentheobject,towhichquantummechanicsapplies,andtheobserver,towhichitdoesnot.Quantummechanics,theysay,isuniversal,becauseanythingwhatevermaybeplacedontheobjectsideoftheboundary,butitisnotclosed,becausenoteverythingcanbeplacedthere.Therefore,theboundarydoesnotmarktheplacewheremindactsuponmatter;rather,wedrawit,somewhatarbitrarily,

becauseof"alogicalnecessityofanytheorywhichisself-referential,asitattemptstodescribeitsownmeansofverification"(p.810).

Suchisnotthecase,however;thegoalofobjectivityisnotlost.Toseethis,considertheexampleofSchroedinger'scat.Inthatexperimentwecanavoidtheproblemsofself-referenceifwestepoutsidethelaboratoryanddeterminetheanimal'scondition

byquestioningthepersonwhoisperformingtheexperiment.Indoingso,ofcourse,weassumethatwhenwereceiveananswertheeditingofpotentialitieshasalreadyhappened,invirtueoftheregisteringofthesurvivingscenariointheconsciousnessoftheotherperson.Thisassumptionallowsthestorytellertodealwiththeinterfacebetweenobjectandobserverwithouthavingtorefertohimself.Notonlydoestheassumptionsavethetheoryfrompossibleproblemswithself-reference,butitisoneweshouldwishtomakeinanycaseindeed,wehavealreadymadeit.Itamountssimplytochoosingagainstsolipsism.Inthisexamplewereaptwoadditionalbenefits:Wegainareasonfordrawingthelinebetweenobjectandsubjectwherewedo;namely,thatquantummechanicsdetailstheactivitiesofmaterialparticlesbutnotofminds.Andwecancontinuetostandoutsidethestorywetellabouttheworldoutthere.Thestoryteller'sownmentality,specialconcerns,andvaluesstillarekeptfromcomplicatingthetale.Mentalitypersehasnotbeenexcluded,becausethestorymentionstheotherperson'smind;buttheprogramofobjectivitysurvives.

Causation.

Becauseobjectscomeintwogeneraltypes,wecanimaginethreebroadcategoriesofcausalactivity:interactionsamongmaterialthings,betweenmatterandmind,andamongmentalentities.Thefirstcategory,includingthegravitational,electrical,andotherinteractions,hasformedpartofthetraditionalsubjectmatterofthesciencessinceNewton.Interactionsofthesecond,whichcausemindstoundergoconsciousexperiencesandparticlestomakethetransitiontoactuality,havebeenaddressedbyphysicalscienceforthefirsttimeinthequantumtheory.Ishallraisesomequestionsaboutbothinthefollowingparagraphs.Butconcerningthethirdimaginablekindofinteraction,thedirectactionofminduponmind,Ishallhavenothingtosay.Thequantumtheorydoesnotspeakaboutit,andwhatfewdatawehaveontheissueareanecdotalor,ifsystematic,stillmoot.Ido

notdenythepossibilityofextrasensoryknowledge,butIshallbasemydiscussiononthesuppositionthatcommunicationalwaysoccursthroughtheemploymentofsoundwaves,signalflags,thepostalservice,orsomeothermaterialbearerofmessages.

Somedistinctionswillbehelpful.Ishallcallthesortofinter-

actionthatgoesonamongtheobjectsthemselvesprimarycausation,todistinguishitfromandgrantitpriorityoverthecorrelationswediscoverinordinaryexperienceandthroughscientificstudy,whichIshallcallphenomenalcausation.Inordertomakesenseoftheexperiencedcorrelationswemustconceiveofprimarycausation,butwedonotknowitexperientially,becauseitoperatesbehindtheexperientialscenes.

However,primarycausationdoesnotlieentirelybeyondourgrasp.Inperception,andperhapsinvolitionaswell,themindinteractsbyprimarycausationwiththematerialobjectsofknowledge,throughthemediationofthebrain.Hereisasingleexampleofprimarycausalinteractionofwhichwehavesomethingthatgoesbeyondhypothetical,conceptualknowledgeinfact,akindofdirectintuition.Whenanobjectactsuponthesubject,notonlyisthemindcausedtoundergoexperientialepisodes,butitalsofeelsconstrainedbyanindependentreality.Hereweencounterthecausalinteractionamongthingsinthemselvesfromwithin,asitwere.Ourfeelingofpassivityinreceivingsenseimpressionsandoursenseofbeingcausallyactivewhenchoosinganddecidingareexamplesofakindofintuitiondistinguishablefromthesensorymodeofknowing,thoughnot,ofcourse,separablefromit.Togethertheyamounttoadirectexperienceofthesubject-objectrelation.Thisisanintuitionoftheinteractionbetweenamentalentityandtheexternalmaterialthingweconceiveof,throughinterpretingthephenomena,asthecerebralcortex.

Livingwiththisintuitivegraspofcausalagency,weareboundtofeeldisappointedwiththepictureofcausationthatemergesfromphysics.Phenomenalcausationisunsatisfyinglyinert.Evenpotentialenergy,whichatfirstglanceseemsliketheactiveprincipleweseek,turnsouttohaveanexplicationintermsofthesame"constantconjunctions"thatwecodifyintheequationsofmechanics.AsDavidHumesaw,wecantellthatphenomenalcorrelationismerelytheappearanceof

causalactionwithoutthesubstancethereofbyitsfailuretodisplayanyhintofnecessity.Thenecessityandinitiativeareboththereintheobjects,but,exceptforthecompulsionwefeelwhenreceivingsenseimpressionsandtheinitiativewethinkweexercisewhenchoosing,theactivepowerdoesnotreachintoourexperience.Insofarasitresidesintransactionsamongotherthingsthanourselves,wedonotand,

itseems,cannottouchit.How,then,dowecometoknowaboutcausalactivitiescarriedonbymaterialobjects?Weknowthemonlyhypothetically,byspeculatingabouttheordinarycorrelationsofcommonsenseexperience.

Space-time.

Havingmadearadicaldistinctionbetweenobjectsandtheirappearances,wemustviewthespace-timeofphysicsasbelongingtothephenomenalrealm.Itisnotacontainerforthemindsandparticlesthatcomposetheobjectiveworldbutthemanifestationinexperienceoftheformalstructureoftheinteractionsthattakeplaceamongthematerialobjectsonly.Thesubjectivequalitiesofspaceandtimethevastnessofspace,forexamplearegeneratedbythemind;likeanyothersensoryqualities,theyareactivitiesthatmindsdo.Butthestructureofspace-time,aswehavelearnedfromEinstein,isasubjectforempiricalresearch.Webuildourunderstandingofphysicalgeometryuponmeasuredrelationsamongevents.The"points"ofspace-timearephysicalevents,andthesecomeinjusttwokinds:First,therearetheactuallymeasuredones,inwhichacausalinteractiontranspiresbetweenanobjectandameasuringinstrument,forinstance,theregistrationofamovingparticleatacertainlocationbyitscontactwithadetector.Second,thereareotherevents,notdirectlymeasuredbutinferredfrommeasurements,forexample,thepassingofaphotonthrougharegionofemptyspace.Thissort,thoughitmaynotinvolveactualcausalinteraction,neverthelesscanbeconceivedofonlyintermsofphysicallypossibleinteractions:Ifadetectorhadbeenwaitingatthelocationofthemovingparticle,itwouldorQ-possiblymighthaveregistereditspresencethere.Space-timeconsistsofasetofrelationsamongactualandpossiblecausaltransactions,transactionsthatwedonotdirectlyexperiencebutmustconceiveofinordertomakesenseofourexperiences.Thegeometricalstructureofspace-timeistheshadowcastonthescreenof

experiencebythelimitationsthatinhereinthoseinteractions.

Abouttheobjectsthequantumtheorycansayonlyalimitedamount.Constructedtobeameansofhelpingusmakeconceptualsenseofourexperienceoftheworld,itcannotgiveusexperientialknowledgeoftheobjectsthatliebeyondexperiencesandhelptoshapethem.Quantummechanics,likeanyotherphysicaltheory,canaidusatmostonlyinconceivingofthem.Morenodoubtgoeson"outthere"thanwecanevercaptureinwordsand

concepts.Conceptualknowledge,henceallofscience,mustbeincompleteinthissense.Theincompletenessisnotapeculiarfaultofthemoderntheory,notademeritincomparisonwithclassicalmechanics;rather,itisanessentiallimitonanyconceptualknowledgeofthatwhichcausesourexperiences.

PuzzlesandConjectures

Withthesebroadoutlinesofanepistemologicalandontologicalprogramtoguideus,letusproceedtotesttheprogramandourinterpretationofthequantumtheorybyposingsomequestionsandproposinganswerstothem.Thepurposeofthisexerciseisnottoestablishanysolidfactsaboutthequantalworldpicture.Rather,IwishmerelytosubstantiatewhatIclaimedabove,thattheactivitylicensedbyarealistic(orcrypto-realistic)interpretationofthequantumtheoryispreferabletothesilencethatfollowsuponamerelyinstrumentalistinterpretation.

DoesMindActUponMatter?

Withregardtomind-mattertransactionswehaveassumedthatmindsplayarolenotonlyinreceivingtheactionofmatterbutalsoinreactingonittocatalyzeactualizations,andperhapsmore.Thetransitiontoactualityoccursintheobjectiveworld,asacorrelatedgroupofatomicparticlesisshornofpartofitsaccumulatedwoolofpotentiality,therebybecomingmorenearlydefinitewithrespecttothosepropertiesthatconnectittoaconsciousexperience.Thisactionisperformedbythegroupofcorrelatedparticlesbecauseofthemind'sreactionuponthem.Theyactinconcert,asapeculiarsortofunit,sothattheactualstateburstsintothespace-timemanifoldlikealogbobbingupthroughthesurfaceofapond.Oneendmaybreakthesurfaceslightlylaterthantheother,andifthelogisverynearlyhorizontalthetwoeventsmaybesonearlysimultaneousthata

physicalsignalcannotmovefromonetotheother.Thoughtheyareconnected,neithereventcausestheother.AnalogouslyintheEPRexperiment,theactualizationsofparticlesthathaveinteractedinthepastareconnectedandcorrelatedwithoutbeingphysicalcausesoneofanother.Sothiskindofactionintrudesuponthefabricofspace-timewithoutdisruptingitscausalstructure;itsthrustrunsnotwithinthemanifoldofactualitybutacrossit.

Thisuniquelyquantum-mechanicalactivityoffersanewper-

spectiveonmind-matterinteraction.Ifthisisthewaymindtrafficswithmatter,thenoneofthetraditionalperplexitiesofinteractionismisneatlyaverted,namely,thequestionastohowamindcoulddeflectanatomfromitsappointedpath.Minds,asagentsofactualization,standoutsidetheatoms'scrimmage,neitherpushingnorbeingpushed.

AreMindsMerelyPassive?

Letusseewhetherwecandowithouttheassumptionthatmindreactsuponmatter.WehaverejectedHeisenberg'sconjecturethatthetransitiontotheactualoccursatthepointofcontactbetweentheatomicobjectandthemeasuringinstrumentandhaveplaceditinsteadonthedoorsillbetweenmatterandconsciousness.Butwehaveacceptedwithoutcriticismhissuggestionthatdefinitenessistobefoundnotonlyinoursubjectiveexperiencesbutalsointheobjectiveworld.Suppose,however,thatdefinitenessobtainsnowhereinthematerialorderbutonlyonthementalsideoftheportal.Perhapsthemindachievesthedefinitenessofitsexperiencesmerelybyfiltering,byrefusingtoacceptforhomeviewingallbutoneofameasuredobject'spotentialproperties,whileleavingthemalltocontributetothething'sobjectivestate.

Thisconjecturewillshowinasomewhatclearerlightifweaskarelatedquestion:Whentwospectatorsviewthesameapparatus,dotheirmindsexperiencethesameactualstateoftheobject?Herewefaceaperplexitythatcannotberesolvedbydoinganexperiment;theproblemofintersubjectiveagreementtroublesusjustasdeeplyinquantum-mechanicalasinclassicaldualism.TheinabilityofthequantumtheorytoanswerthequestionmaybeseenbyapplyingtheanalysisoftheEPRexperimenttothecaseoftwoobserverslookingatthesameapparatus.Tomaketheillustrationmorelurid,letussupposethattheobservedobjectisthecat(butamindlessone)ofSchroedinger'sparable.Thetwogroupsofphotonscarrying

informationfromthebodyofthecattotheeyesoftheviewersactlikethecorrelatedparticlesintheEPRexperiment,becausetheyoriginateinthesameobject.Astraightforwardapplicationofthequantumtheoryproducesdescriptionsoftwoprincipalpotentialstatesofthecoupledmaterialsystemthatconsistsofthecat,theambientlight,andthebodiesoftheobservers.InonepotentialstatetheGeigertubereceivestheatomicparticle,thecatliesinertonthefloorofitsbox,

imagesofitssorrystateformupontheretinasofbothspectators,theirbrainsencodetheretinalimages,andsoundsofdismayissuefromtheirthroats.IntheotherpotentialstatetheGeigertubeisuntouched,theanimalspringsfromitsprison,theretinalimagesofthisescapetakeshape,thetwobrainssupportthecorrespondingpatternsofneuronalfirings,andthevocalcordsofbothpersonsgeneratetonesofgratification.Finally,thequantumtheoryproducesnoassertionofapotentialstateofthiscorrelatedsystemsuchthattheretinaandvisualcortexofoneobserverrecordadeadcatandtheother'salivingone,noriseither'svisioncontradictedbywhathehearstheothersay.Moreover,ifanysingleobserverlookstwiceatthecat,thepotentialstatesinducedinthatperson'sbrainareself-consistent.Insomepotentialscenariosthecurrentimageinducedbythesecondinspectionandthememoryleftbythefirstonebothrecordalivingcat,andinotherstheyrecordadeadone;butinnonedothepresentimageandthememorydisagree.(See,e.g.,Everett1957.)

Nowletussupposethatthefirstviewer'smindpassivelyreceivesjustoneofitsbrain'scollectionsofcorrelatedpotentialpropertiesintoitsownmerelysubjectiveactualitywhileleavingallpotentialitiestocontributeundiminishedtothestateofthematerialobject.Onthatsuppositionwewouldexpectthesecondperson,onglancingatthecat,tobeabletoreceivethealternativepotentialworldintoconsciousness.Becauseeachpotentialworldcontainsonlymutuallyconsistentvaluesofthecorrelatedproperties,eventhepropertiesoftheotherobserver'sbody,neithermindcouldbeawarethattheotherhasactualized(thatis,passivelyreceived)adifferentpotentialworld.Consequently,thehypothesisofpassivereceptionwithoutacorrespondingreductionofpotentialityinthematerialworld,includingthebrain,leadstoseriousdoubtaboutagreementamongminds.

Thosedoubtsmightberesolved,orratherpreventedfromarising,by

followingSchroedinger(1956;1958)eastward,thatis,byadoptingametaphysicsinwhichtherearenotmanyindividualmindsbutonlyoneuniversalconsciousness.Nevertheless,althoughbythispostulatewecouldavoidthequestionofwhetherdistinctmindsagree,wecannotavoidacloselyrelatedproblem,alsogeneratedbythesuppositionthattheobjectsretaintheirtendencies.Theproblemconcernstheagreementofasinglemindwithitselfoverstretchesoftime.

Themind,weknowfromintrospection,neverexperiencestheworldintoto;rather,impressionsofobjectsenterconsciousnessofteninsmallpiecesandhaphazardly.Therefore,asanobserverpeerstwiceinsuccessionintothecat'scage,twoopportunitiesarepresentedtothematerialsystemtodeliveroneoranotherofitspossibleexportstoconsciousness.Letussupposethatinthefirstinstancethelotfallsontheexperienceofadefunctcat.Ifthematerialobjectretainsitsfullrangeofdispositions,thebrainstillhastwotendencies:todeliveracurrentexperienceandamemoryofadeadcat,andtodeliveranexperienceandmemoryofalivingone.Consequently,whentheexperimenterlooksagain,themindmayreceiveinthesecondshipmentasubjectivestateconsistentwithinitselfbutinconsistentwiththeearlierexperience.Wouldthepersonknowthatsuchathinghadhappened?Notunlessamindkeepsastoreofmemoriesapartfromitsbrain.Adiscrepancybetweensuccessiveexperientialstatesofasingleobserverwouldremainundetectedforthesamereasonthatasimilardiscrepancybetweendistinctviewersalsogoesunnoticed:Ateachmomentaperson'sexperienceistotallyself-consistent,bothwithregardtohisownmemoriesandwithregardtothephysicalcharacteristicsoftheotherspectator.

Wefindthatthehypothesisofpassivityleadstoaradicalskepticismnotonlyaboutthestatesofothers'mindsbutalsoaboutthepaststatesofone'sown.Surelywestarehereatasolipsismofthemostadvanceddegree.Howcanweescapeit?Onlybyadopting(aswearefreetodo)themosteffectivereplytosolipsism,thatis,bychoosingnottobelieveit.

Passingon,then,toanalternativeconjecture,letusassignaslightlymoreactiveroletothemind.Supposethattheregisteringofanexperienceinconsciousnesstriggersareductionintherangeofpossibilitiesobjectivelypresentintheobservedsystem.Thisconjecturewouldgiveusareasontobelievethatdistinctmindsagree

astotheactualvaluesofthevariablepropertiesofthings.Oneobserverlookingatasystempreviouslyinspectedbyanother,orthefirstobserverlookingagain,wouldhaveanexperienceconsistentwiththefirstobservation,becausealltendenciestoproduceinconsistentexperienceshavebeenrootedoutoftheobjectiveworld.Theyarenolongertheretobeactualized.Thus,thethreatofsolipsismrecedes.

Havingreadoptedtheinteractionistconjecture,wemustcom-

pileaninventoryofnew,fundamental,andthereforeunexplainablefactsaboutmentality.Totheheadofthelistgoestheabilityofabraintoinduceamindtoperformspecificconsciousepisodes.Theotherendofthissameinteractionisthemind'sabilitytoinduceanactualizationinthematerialsystem.Thisreactionofminduponmatterraisesanotherquestion.

DoesaMindDirectWhatMatterDoes?

Doesthemindmerelytriggertheactualization,lettingtheoutcomefallasitmay,ordoesitsometimesselect?Mostevidenceindicatesthatthemindisverypassiveindeed.Thatcertainlyisthecaseinordinaryperception.Thebrainlaborsvigorouslyininterpretingtheincomingstimulibyrecognizingpatternsandprocessingsignalsinvariousways,buttheminditselfsimplyreceivestheresultofallthisactivity.Itisjustourfeltpassivityinthisrelationshiptotheexternalworldthatgeneratesoursenseofbeingacteduponbysomething"outthere."Inouremotionallife,too,matteroftenactsuponmind;fear,joy,lust,awe"overcome"us;theyarecalledpassionswithgoodreason.Inaddition,wehavenotedabovehowmuchthatcountsasintelligencesuchactivitiesassolvingproblemsandinventingplotsfornovelsiscarriedoutbytheunconsciousmachineryofthebrain.Byandlarge,brightideas,suchasthesolutiontoananagramortheprincipalthemefortheadagiomovement,simply''occurto"us.Inthesecasesmatter,principallythebrain,istheactivepartyandmindthepassiveone.Indeed,thereisonlyoneareaofhumanexperiencewherealmosteveryonefeelsthatthemindassumesanactiverole,namely,inmakingdecisions.That,Isay,isthenearlyunanimousfeeling;whetheritcanbesupportedbyreasoningbasedonsolidevidenceremainstobeseen.AtthispointIsimplynotethesubjectivefact:Weseemtobeconnectedwithexternalrealityquitedifferentlywhenorderinglunchthanwhentastingit.

Thereseems,indeed,tobeacertainlackofsymmetrybetweentheactiveandpassiveinvolvementsofmindwithbrain,betweenwillingandsensing.Ofthemultiplicitythatquantummechanicsassignstoexternalthingswegetnointimationinanyinstanceofsensing,butwedosometimesexperiencesomethingratherlikeasuperpositionofseveralpotentialalternativeswhenengagedinchoosingamongoptions:Occasionally"yes"and"no"seemreallytofloattogetherinsomevestibuletotheworldofactuality.

Ifamoralcanbedrawnfromthisobservation,itwouldbethattheactiveconnectionofmindtomatterdiffersinsomerespectsfromthepassive,thatwhenactivelychoosingwetouchsomepotentialitiesbeforetheyareerased.

Althoughnoneoftheseanecdotesfromcommonsubjectiveexperiencecarriesenoughweighttocompelustowardoneconclusionratherthananother,theyaretheonlyclueswehave.Letusseewhatcanbedonewiththem.

HowDoestheTransitiontoActualityOccur?

Doparticlespassonactualityfromonetoanother?Doesitprogresslikethefallofalineofdominoes,withthelossofpotentialvaluesofsomepropertybyasingleatominthecortextriggeringcorrelatedlossesinitsimmediateneighbors,andsoon?No;asIhavearguedabove,noprincipledaccountcanbegivenofthistriggeringthatdoesnotattributeittotheinteractionbetweenmindandmatter.Well,then,whatmechanismmediatestheinteraction?Thisquestion,too,includesamistakenassumption.Weshouldnotexpecttogetanswersbyborrowingfromatomisticwaysofthinking.

Therearetworeasonsagainstforcingatomisticanalogiesuponmind,oneevidential,theotherprudential.Astoevidence,wequitesimplyhavenonethatpointstowardanatomicconstitutionofmind.Theoriginalimpetustowardanatomichypothesisformattercamefromtheobservationthatmostsubstancesadmitofdivisionintoparts,whichmanagetoexistontheirownwhileretainingsomeofthepropertiesoftheparentlump.Butinmindswefindnothinganalogoustothepartitioningofablockofmarbleintosolid,sharp-edgedchips,orofabarrelofbeerintoindependentlydrinkablepints.Iconsiderthissortofdivisibilitytobeanecessaryconditionfortheplausibilityofanatomichypothesis;withoutit,otherindicationsofmultiplicitywillsettlemorecomfortablyintootherconceptualschemes.The

prudentialconsiderationisthis:Extendingatomismtothementalspherewouldentailabandoningapromisingprogram.Theatomichypothesisconflictssharplywithsomeentrenchedintuitionsabouthumanbeingsascausalagentsandabouttheunityofconsciousness.Introducingmindsasagentsofanentirelynewsortofcausalactionpromisestobringontologyintolinewithintuition.Ofcourse,agreementbetweenintuitionsandscientifichypotheses

doesnotguaranteetruth,forbotharefallible,butaclashbetweenthemmustbetakenasawarning;hence,flagsofpeaceareawelcomesight.Anatomichypothesisappliedtomindwouldrescindthepromiseofharmonybyreintroducingtheproblemofunityalsointhisothercategoryofbeing.

Wedofindinmentaleventsamultiplicityofsorts,butitseemstobeamultiplicityofactivityratherthanofcomposition.Ihaveurgedasaprincipleofmethodthatweconceiveofmentalepisodesasactivitiesofmindratherthanascomponentparts.Wesaythataminddoesseveralthings,perhapsevensimultaneously,butwerefrainfromsayingthatitconsistsofseveralpieces.Iftherewereanyprimafacieevidencetomakeanatomicconjectureplausible,thenextstepwouldbeprescribedbyparadigmsdrawnfromtheatomictheoryofmatter:Havingrecognizedmultipledoingsorundergoingswewouldpostulatemultiplesubstantialparts.Instandardatomismnointrinsicchangeoccurs;apparentexamplesofitareshowntobechangesmerelyinthespatialalignmentsandinteractionsoftheenduringatoms,notintheirintrinsicproperties.However,wehavenoevidencethatanythinglikethatgoesoninmentalepisodes,norhaveweanycluetowhateithertheeternal,intrinsicpropertiesortheextrinsicrelationsofmentalatomscouldbe.Weneedanentirelynewwaytoconceiveofchangewithtranstemporalself-identity.Tounderstandmentalactivity,weneedaconceptualschemecutloosefromtheprogramofDemocritus.

WhereDoMindandMatterTouch?

Justwhereinthebraindoesthemindcontactmatter?Whereisthepointofentryfromoneworldtotheother,andifitisaportalratherthanamathematicalpoint,howwideisit?Thebizarreflavorofthesequestionssurelyrevealsanunderlyingconceptualmuddle.Thequestionsassumethattheinteractionoccursinspace,butwemustnot

treattherelationbetweenmatterandmindonthemodelofthatbetweenparticleandparticle.Howeverwemaycomeeventuallytothinkaboutthismetaphysicaltransaction,wemustnottrytopushitintothewebofspace-time.AsIhavearguedabove,space-timeisthephenomenalmanifestationoflimitationsintheinteractionsamongtheparticles.Wehavenoreasontoexpectspatiotemporalrelationsalsotomanifestlimitationsintheinteractionbetweenmindandmatter.

Whereisthepointofcontactbetweenmindandmatter?Thisquestionrequiresdelicatehandling.Wemaychoosetoreaditliterally,understandingbythepointofcontactbetweentwothingstheregionofspacethattheyoccupyjointly.Onthatreadingthe''connection"hasnolocation.Becauseitdoesnotexertorsufferphysicalforces,aminddoesnotliveinthespatiotemporalworld.Ifweinterpretthetermmoreloosely,stipulatingthatthepointofcontactistheplacewherethemind'seffectismanifested,thenthepointturnsouttobethegerrymanderedregionoccupiedbyalltheparticleswhosepotentialitiesareprunedinthereductionofthewavefunction;andthissphereofinfluencemayextendfarbeyondtheconfinesofthebody,andevenofthegalaxy.Bothoftheseanswershavetheirmerits.Butamorenearlycommonsensereadingofthequestionpromisesafairlycommonsenseanswer.Letusdefinethe"contactpoint"asthesetofmaterialobjectswhich,intherelevantexperience,affecttheminddirectly,notthroughphysicalinteractionswithotherthings;inthatcaseempiricalresearchislikelytoidentifyafairlysmallregionofthebrain,asmallbutshiftingsetofcorticalneurons,asthephysicalsideofthedoorbetweenmatterandmind.

Butwhatastrangedoor.Whyisthepassagebetweenthetwoworldspositionedjustthere?Invirtueofwhatpropertydotheneuronstakeontheirvestibularrole?Or,iftheneuronsarenotwhollyresponsibleforthisliaison,whatpropertyofmindsdisposesthemtoadoptbrains,andnotsomeothercomplicatedassemblyofatoms,astheirmeansofcontactwithmaterialobjects?Itseemsobviousthatnosortofanswertothesequestionscanbelookedforfromtheatomistprogram.

HowCanThereBeActionataDistance?

Nowheredoesquantumtheorydeviatemoresharplyfromthetraditionalprinciplesofnaturalsciencethaninitsassertionthatasinglemeasurementcaninducewidelyseparatedparticlestoadopt

definite,correlatedvaluesofcertainproperties.Quantumnon-localitydoesnotcontradicttheprinciplethatthecausalactionofoneparticleonanothermustoccurbymeansofintermediariesthattravelatfinitespeedsacrosstheinterveningspace.Inthetransitiontoactualitynoforcesareexerted,nophotonsorgluonsareexchanged.Ithappensnotbecauseofinterplayamongparticlesbutbecauseofaninteractionbetweenmindandmatter.

Nevertheless,averygreataffrontisofferedtoourrootednotionsabouttheabsoluteimportanceofspatialseparationasalimiterofcausalinteraction.AsIhaveinterpretedit,thecollapseofpotentialitiesinwidelyseparatedparticlesseemstoputamindonintimatetermswith(tosay"incontactwith"wouldintroducepreciselythewrongmetaphor)anynumberofparticlesanywhereintheuniverse.

Theparticlesconducttheircausalaffairsaccordingtotheirownregularandlimitedways.Thepotentiality-limitingactivityofamindinnowayabrogatestheorderlinessofthoseactivities.Butwemustremorselesslydeflatetheclaimsofphysicalspace-timetobethearbiterofallprimarycausation.ThedauntingvastnessofthespacebetweenearthandtheAndromedagalaxyisnomorethanthemanifestationinconsciousnessofwhatlittlewecanresonatewithintherulesofinterparticlebehavior.Onefeelsthestrongestreluctancetosupposethatamindcouldinduceaprotoninanothergalaxyimmediatelytolosesomepotentialpositions;yetthisfeelingamountstoanillicit(thoughwellnighirresistible)applicationtoonekindofinteractionofrulesthatinformanotherandfundamentallydifferentkind.

Thoughwecannotexperientiallyknowprimarycausation,yetwemustconceiveofit;what,then,canwesayaboutit?Negatively,wecansaythis:Becauseittakesplaceamongobjectsthatliebehindandtranscendourexperience,primarycausationalmostcertainlytranscendsitsownphenomenalappearance;inparticular,itincludesatypeoftransactionnotfoundanywhereinsensoryexperience,namely,theinteractionbetweenmaterialobjectsandamind.Weshouldnotassumethatthistypeofprimary-causaltransactionwouldshowmuchsimilaritytothesortthattakesplaceamongmaterialobjects,whichweexperiencephenomenallyasforces.Thelatterhavetheirowncharactersandinherentlimitations,whichmanifestthemselvesas

spatiotemporalcontiguityandseparation.Consequently,althoughthemaxim"noactionatadistance"appliestothephenomenalmanifestationoftheprimary-causaltransactionsamongtheparticles,wehavenogroundforsupposingthatasuitabletranslationofitcanbeappliedtoaradicallydifferentkindoftransaction,namely,thatbetweenmaterialobjectsandconsciousness.Thereductionofthewavepacket,thecorrelateddeletingofquantum-mechanicalpotentialities,isnotachievedby

oneparticleexertingaforceonanother;hence,wehavenoreasontoexpectthattherulesbywhichweexpressthepossibilitiesandlimitationsofthetransitiontoactualitycouldbestatedinthelanguageofspace-time.

CanMindInterfere?

Thepotentiality-editinginfluenceofamindreachesnotonlytotheparticlesdirectlyunderobservationbutbeyondthemtocorrelatedparticleswidelyseparatedinphysicalspace.Opportunitiesshouldsometimesarise,therefore,forasingleparticletobeimplicatedinthetransitionsbeinginducedsimultaneouslyinseparatelaboratories,thoughthelinkingparticleisnotpresentineither.Inthatcase,thedefiniteresultexperiencedbyoneconsciousnesswillhavebeenachievednotbyinteractionwithitsownmeasuringinstrumentbutbytheothermind,eventhoughnocommunicationoftheusualsorthaspassedbetweenthem.Thissoundsuncomfortablylikealicenseformentaltelegraphy.Hence,wemustask:Isthereanynaturallimitationontheabilityofourmindstotamperwithperceivablestatesofaffairsfarremovedfromordinaryspheresofcausalinfluence?

Indeedthereissuchalimitation.Itarisesbecausemostpotentialstatesofaffairsatthelevelofparticlesdonotcorrespondtodistinctstatesofconsciousness,andonlythosethatdoareeligibleforerasureinthetransitiontoactuality.Considerjustoneartificialbutrevealingexample.SupposethatanexperimentoftheEPRsortproducesapairofelectronsfromaninitialstateofzeroangularmomentum.Theseparatingparticlesthenhavecorrelatedpotentialvaluesfortheirspinsalongacontinuousrangeofdirectionsperpendiculartothelinealongwhichtheyseparate.Lettheleft-handparticleencounteramagneticfieldorientedvertically,sothattheelectronisobligedtoadoptadefinitespinvaluealongtheverticalline.Letussettwoparticledetectorsbeyondthisanalyzingmagnetinsuchawaythata

particledeflectedupwardentersoneofthem,triggeringatrainofelectricalsignalsthatterminatesinthelightingofaredlamp;andadownwarddeflectedparticlelightsagreenlamp.Intheleft-handbeamweplaceacorrespondingarrangementofanalyzingmagnet,detectors,andredandgreenlamps,buttheretheseparationoccursalongahorizontalaxis.Whentheright-handparticleundergoesitstransitiontoactualityletussaytotheupwardorientation,

lightingtheredlamptheleft-handparticleadoptsadefinitedownwardorientation.However,bothparticlesretainthecompleterangeofpotentialitiesfororientationsalongthehorizontalaxis.Consequently,theleft-handelectronhaslostnoneofitsoptionswithregardtoahorizontaldeflectionandmayQ-possiblytriggereithertheredorthegreenlampatitsend.Thepotentialoutcomesofmeasurementatoneendoftheexperimentarequiteindependentofthoseattheother.Therefore,thetransitionstoactualityinducedbyanobserversittingatonedetectingstationwouldnotlimittherangeofpossibleredorgreenexperiencesofsomeoneattheotherend.

Indeed,theexperimentmustbecarefullycontrived,asitwasintheprototypeinventedbyEinstein,Podolsky,andRosen,inordertoavoidthisorthogonality,oranearorthogonalitypracticallyindistinguishablefromit.InthestandardexperimentsoftheEPRtypethathavebeencarriedout,analyzersareindeedsetupatotherthanexactlyorthogonalangles,buteveninthesecasesonlyextendedrepetitionsoftheexperiment,statisticallyanalyzed,areabletomanifestthequantumcorrelation.Individualtrials,orhaphazardsetsofthem,thesortofthingthatcasualobservationoftheworldconsistsofalmostexclusively,wouldfailtoturnupanythingnoticeable.Inthegeneralcase,theperceivableconsequencesofthecollapseofQ-possibilitiesatonelocationcorrelatingwithacollapseelsewherewouldbenegligible.

Ithinkitisobviousthatwecaneasilygeneralizethisresulttocaseswheretheorthogonalityisnotspatialbutisquiteaseffectiveasinthisexample.Particlesandthemorecomplexsystemsthattheyencounter,lefttothemselves,cannotbeexpectedtosortthemselvesintoalignedmeasuringdevices.Thephysicalinteractionsthatleadeventuallytoaperceptualexperienceinoneobserver'smindwillnormallynotalterinanynoticeabledegreethepossibleexperience-generatinginteractionsinanother'sperceptualapparatus.

Andifthislackofspontaneousalignmentistheruleinexternalthingslikeparticledetectors,wemaybesurethatonlyafantasticcoincidencecouldproduceaperceivablecorrelationintheQ-possibilitiesthatburgeonwithindifferentbrainsasaresultofthesignalprocessingandlogicalmanipulationsthatoccurthere.IfpersonsmakechoicesbyselectingfromamongQ-possibilitiesthataregeneratedinthebrainandpresentedbyittoconscious-

ness,differentvolitionalagentswillactupontheirownoptionswithpracticallycompleteindependence,despitetheuniverse-widecorrelationthatquantummechanicsreveals.

Shouldwewonderwhichoftwospectatorsreallytriggerstheactualizationofanextendedsystemwhenthetwoexperienceshappensoclosetogetherintimeandfarapartinspacethatnophysicalsignalcouldconnectthem?No,wehaveseenthatquestionsabouttemporalpriorityinsuchcaseserroneouslyimplythatthetriggeringofatransitiontoactualitytakesplacewithinthespace-timemanifold.Nocausationintheusualsensethatis,nopushingofparticleagainstparticlegoesoninanactualization,andbothobserverspassivelyreceiveitsresults;hence,theanomalouspossibilityofsignalingfasterthanlightdoesnotarise.

CanaMindSelectPotentialStates?

Considerafurtherspeculation,whichgrantsastillmoreactiveroletomindsandraisesadifficultquestionaboutcausalpriority.Supposethatonoccasionanindividualmindcanactivelyselectwhichofanobject'spotentialstatesshallbecomeactual,"grantingconsenttoonepossibilityandwithholdingitfromanother,"asWilliamJames(1897)describesvolition.Couldwemaintainsuchaconjectureconsistentlywithwhatwehavelearnedfromquantummechanics?

Hereweraisethepossibilityofviolatingtheprinciplesofspecialrelativity.Toseethis,consideranEPRexperimentinwhichthetwoobserversmeasurethepolarizationofapairofcorrelatedphotons.Letoneofthempassivelyreceiveandtheotheractivelyselectthestatetobeactualized,withtheselectionoccurringinsuchawaythathorizontalandverticalpolarizationsturnupwithroughlyequalfrequencyinthelongrun.Evenwiththisrestriction,theactivemindcouldselectastringofhorizontalandverticalactualizations(correspondingtothezerosandonesofabinarycode)thatcarrya

message.Then,becausetheactualizationsofthetwoseparatedpartsofacorrelatedsystemhappensimultaneously,theactivepersonwouldbeabletotransmitasignaltotheotheronewithlessdelaythanwouldbeexperiencedifanactualphysicalintermediarytraveledfromsendertoreceiver.Butasuperluminaltransferofinformation,accordingtospecialrelativity,entailsthepossibilityofsendingsignalsfromthepresent

intothepast,aswellasotherparadoxesofcausation.Thatun-comfortableresultmightprovidereasonenoughfordiscardingthehypothesisofactiveselection.

Wecouldavoidtheparadoxesbyplacinganattractivebutadhocrestrictiononthehypothesis.Intuitionsuggeststhatchoosinginfluencesonlythecausalchainsthatproceedoutwardfromourbrainstotheworldofobjects.Wecertainlyfeelpassiveenoughwhenmerelyperceiving:Bothscientificexperimentsandhorseracesfrequentlydefyourexpectations.Ouractiveinterventionintheworld'saffairsseemstobelimitedtotheoccasionswhenweassertourselvesindeedsorwords.

Suppose,then,thatamind'sdirectpowersofactiveselectioncanreachonlythosepotentialstatesofitsbrainthatarenolongercoupled,viaEPRcorrelations,withotherportionsoftheuniverse.Thatsuppositionisplausiblebecausetherequiredun-couplingofdistant,correlatedobjectsdoesoccurjustwhereitisneededintheinteractionsthataccompanyobservations.Forexample,iftwodistantparticleshavecorrelatedvaluesbothofpositionandofmomentum,asintheoriginalthoughtexperimentofEinstein,Podolsky,andRosen(1935),andifanobservermakescontactwithoneoftheparticlesbymeansofaninstrumentthatmeasuresposition,thentheperson'smindinducesthemeasuredatomicobjecttoadoptasingle,definitelocation.Buttheinteractionbetweenthatparticleanditspositiondetectorintroducesbyphysicalnecessityarangeofpotentialmomentaintheparticle,astheuncertaintyprinciplestates.Thesenewpotentialmomentaarenotcorrelatedwiththepotentialpropertiesintroducedatthesitewheretheotherparticleinteractswithitsmeasuringinstrument.Similarinteractions,hostsofthem,occurinthecausalchainconnectingthatinstrumenttoanotherspectator'scerebralcortex.Stillmoreoccurwithinthecortexasitprocessessensorydataandassemblesblocksofneuronalconnections,whichifcalledupon

coulddirectalternativeprogramsofbodilymotion.EachoftheseintroducesfreshpotentialitiesthatbearnocorrelationoftheEPRsortwiththepropensitiesbranchingoutintheotherbody.

Consequently,ifeachmindexertsachoiceonlyoverpotentialbrainstateswhosepropertieshavebeendisconnectedfromthoseofobjectsoutsidethebrain,anonmaterialvolitioncoulddirectthetransitionstoactualitywithoutengenderingaconflictbe-

tweendistinctminds.YetthisinfluencecouldhavemacroscopicallydistincteffectsonpubliclyobservableeventsasdistinctasthetwostatesofSchroedinger'scatbecause,althoughthemindintrudesuponthespace-timeworldonlybymeansofthesecondkindofcausation,itschoicesareamplifiedbythefirstkind,bytheneuronalandmuscularmechanismsthatconnectthebraintothelimbsandlarynx,manifestingchoicesandresolutionsmadeinternally.

Butthisspeculativeexcursion,briefandhesitantthoughithasbeen,haspassedwellbeyondtheterritorymappedoutbythequantumtheory.Itcanclaimourattentionmainlybecauseitfailstocontradictthatspecifictheory,demonstratingbyexamplethehospitalityofquantummechanicstotheideathathumanbeingsinfluencethecourseofeventsasunits.WhereasabeliefinhumancausalagencycouldbeembracedinthenineteenthcenturyonlyinspiteoftheatomisticmechanicsofNewton,thisspeculationshowsthatonecanfitthebeliefintoourpresentintellectualframeworkwithoutdartinganxiousorapologeticglancestowardthephysicslaboratory.

Conclusion

Speculationssuchasthesecouldbemultipliedindefinitely.Butletushaltandtakeourbearings.What,ifanything,hasbeenaccomplishedtowardansweringthereductionistpictureoflivingthings?Theobjectionablefeatureofatomism,asIhaveformulatedit,isthis:Itportrayseveryactivityperformedbyacompositething,evenbyalivingorganism,asnothingotherthanthecompoundedactivitiesoftheparticlesthatcomposeit.Anorganism,inthispicture,doesnotactasacausalunit;itisaspectacleperformedbyamultitudeofactors.Ifweaccepttheatomistontology,thosestatementsfollowalmostimmediately,for,accordingtoatomism,thereisnothingtoperformactivitiesoverandabovetheparticles;havingenrolledthem,wecanfindnothingtoputalongsidethem.Wecan,indeed,designate

conglomeratesofatomsbysinglenamesandthustreatthemasiftheywereunitaryactors,butwehavefoundnoactivitydonebyagroupofatomsthatcannotbeunderstood,andmorethoroughlyatthat,asthesumoftheactivitiesoftheparts.

Tothisunderstandingoftheworlddualismoffersaradicalalternative,becauseitprovidesarichercastofcharacters.Inadditiontothemultitudeofactivitiescontinuallybeingcarriedonbytheatomsthatcomposethenervesandmusclesofalivingorganism,therearealsotheactivitiesofitsmindatleastinhumanbeingsandpossiblyinothersentientanimalsaswell.Thebodilyactivitiesareindeedpluralistic;theyaredonebyathrong.Wehave,however,noreasonfortryingtounderstandthevariousthingsamindcandoasbeingbuiltupfromchangingcombinationsofsimpler,endlesslyrepeatedactivitiesof''mentalparticles.''Thereisnoevidenceforthatviewandnothingtobegainedfromit.Accordingtothespeculativesketchwehavedrawn,theactivitiesofamindareperformedbyaunitaryactor,onenotmerelydesignatedassuchbyothersfortheirownconveniencebutunitaryinitself.

Wedohaveexamplesofunitaryagentsinthematerialrealm:Theyaretheparticlesidentified(provisionally)byphysics.Whatafundamentalparticledoesisnotdoneforitbycomponentpartsithasnone.Yet,despitetheiressentialsimplicity,theseunitscanperformarepertoireofactivities.Aquark,forexample,caninteractwithotherchargedparticlesbysendingandreceivingvirtualphotons;itcanalsoexertforcesonotherquarksbyemittingandreceivingvirtualgluons.Thisexamplediffersinimportantrespectsfromtheunitaryactivitiesofminds.Thecausalactionofthebrainonconsciousnessisnottobeconceivedintermsoftheexchangeofmaterialemissariesbetweentheparticipants.Nevertheless,thecreatingandtheannihilatingoffieldparticlesbyelectronsandquarksdoexemplifyself-containedactivitiesperformedbystructurelessunits.So,also,dotheactivitieswecallmentalevents.Amentaleventorprocessisperformedbyasinglething,amind;itisnottheworkofacommittee.Aswirlingcrowdofparticlesstimulatesthementalactivityandpartlycolorsit.Butwhataminddoesthementalportionofwhatapersondoesin

sensing,imagining,willing,andevaluatingisdonebythatunitaryactoritself,notbyahostofpartsonwhoseexistenceitmightdepend.

ThisspeculationmaybecriticizedonthegroundsthatitrowsagainstthetideofscientificandphilosophicalthinkingthatbegantoflowinthedaysofCopernicus.Wenolongerthinkthat

humankinddwellsatthecenterofthesolarsystem,orisatthecenteroftheuniverse.Wenowbelievethatourage,midwaythroughthelifetimeofthesun,isafairlyrepresentativesliceacrossthelongjourneyoftheuniversefrombigbangtoheatdeath.Wenowunderstandourspeciestooccupyanunremarkableplaceontheevolutionarytree:Thoughwecanclaimtobetheproductofaeonsofevolutionarychange,thesamecanbesaidofeveryextantkind.Eachspeciesisthebestintheworldatwhatitdoes,andnonedoesitperfectly.How,then,canwejustifydistinguishingourselvesasametaphysicalunionofmaterialandnonmaterialactors?Aself-descriptionsoflatteringmustbeviewedwithcaution.

Butitshouldnotbedismissedmerelyonthataccount.Itmayberight,forallthat.Argumentsarenotlackingtosupportthedescription.Theydeservetobestudiedwithcaution,indeed,becausetheyappealtoourself-esteem,butalsowithcarefulattentionbecausetheycarryimportantimplications.

Thisviewofhumannaturewouldlendtheoreticalsupporttoourbeliefthatbenefitsandharmsdonetohumanbeingshavedirectethicalrelevance,whereastheeffectsofouractionsoninanimateobjectshaveonlyderivativerelevance:Ourestimationofethicswouldbesecured.Thisdescriptionwouldmakeroomforthesenseonegetsofbeingintouchwitharealitynotoneselfandnotmerelyparticles,either,whenonecommuneswithotherpersons:Ourestimationofsociallifewouldberatified.Thisviewwouldtoleratetheconjecturethattheexperiencesofmysticsofalltraditionsrevealsomerealitybeyondtheindividualmystic'scentralnervoussystemandhisorherpersonalhistory:Ourestimationofreligioustraditionswouldbeelevated.Theseimplicationsaregroundsfortakingthespeculationseriously,thoughnoneprovidesreasonsforacceptingit.Justasitmustnotbeembracedmerelybecauseitfavorsus,soitoughtnotbescornedjustbecauseitraisesthethreatofirrationalism.Itisgoodto

seethesubtleattractionsofthepositioninordernottosuccumbtothem;buttheargumentsmuststandorfallontheirownmerits.

Throughoutthisbook,Ihavesoughttoreconciletheintuitionsofordinaryexperienceconcerningcausalactionandindividualexistencewiththeinformedintuitionswegetfromscientificstudyofthenatureofthings.Frompersonalexperiencewe

formthenotionsofcausalagencyandindividuality.Fromnaturalphilosophywehearthattheseideasapplyproperlyandprimarilytothefundamentalparticles.Impressedbythesuccessofreductionism,wesuspectthattheydonot,afterall,applytoourselves.Thereisdissonance,indeed.Butwecanrestoreameasureofharmonybyenlargingourontology.TheargumentsIhavecollectedheremakeroomforthedistillationsofordinaryhumanexperienceandthecarefullycraftedideasofrationalsciencetocollaborateinpeace.

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Index

A

Abilities,reductionof,49-54

Achinstein,P.,58,98

Actualityordefiniteness

criterionof,172-74

mindasagentof,221-26

primarysenseof,222

rulesfortransitionto,206-21

transitionto(actualization),159,175,177-78,203-5

Adaptations

cyberneticvs.evolutionary,76-77,102-5,117-18

metaphorical,76-77

Agent,causal,5-6,9,11,12,23,25,30,127-28,140,143,189,191-92,221,224-25,237,244,252-53

ofselection,108,114

Appearanceandreality,231-32

Ashby,W.,88

Aspect,A.,180,182

Astrology,140

Astronauts(andcosmicrays),19

Atomism,4-11,12-32,46-53

Atoms,numericalevidencefor,39

Automaticsteeringmechanism(heat-seekingmissile),81,85-87,97

Ayala,F.,59

B

Beckner,M.,61,63,70

Bell,J.,182

Bigelow,J.,59,63

Blanshard,B.,5-6

Blueprint,135-36

Bond,V.,19

Boorse,C.,58,90,92

Boundaryconditions,67-69,134-38,190

Bub,J.,164

C

Campbell,D.,10,134-38

Campbell,K.,30

Cartwright,N.,217-20

Casteneda,C.,9

Cat,Schroedinger's,177-79

andagreementamongdistinctobservers,240-42

complementedbyDavisson/Germerexperiment,209-10

C

Cat,Schroedinger's(continued)

withmechanisminplaceofcat,199-200

andself-referenceinthequantumtheory,235-36

Categorymistake,17

Causation

causalmechanisms,reducing,20-21

interactionbetweenmindandmatter,239-40

primaryvs.phenomenal,236-38,247-48

Causey,R.,134

ClassicalorNewtoniandeterminism,136

Clauser,J.,180,182

Collapseofthewavefunction(transitiontoactuality),159

asobjectiveevent,182.

Commonsenseandscientificknowledge,33-54

Contexts,functional,spatial,andcausal,131-32

Controlbyupper-levelprocess,134-38

Cooper,L.,211

Cosmicrays,perceptionof,byastronauts,19

Counterfactual(C-)possibility,167-68

Criterion

offeedback,69

ofontologicalcommitment,10

ofpotentialityandactuality,174

ofreality,172

ofselection,109,112,118

Cummins,R.,90-92,105

D

Dalibard,J.,180,182

Darwin,C.,100

Davisson,C.,163,201

Design,55,101

Determinism,5,6,136

DeVries,H.,130

Dewey,J.,116-17

Diffraction

bycrystal(Davisson/Germer),163,201

bydoubleslit,161

byobstructeddoubleslit,162

Discriminating,mere,108,113-15

Dominanceasrelationamonggenes,129

''Downwardcausation,"134-38

Double-slitexperiment,161-62

Drell,S.,13n

Dualism,Cartesian,143,155-56,205,224,227-30,235,240,253

Duality,wave-particle,179

E

Eccles,10

Editing

byhigher-levelprocesses,134-38

ofpotentialitiesbymind,135,243-44,250-52

Einstein,A.,172,180-82

Emergentproperties,8

Enc,B.,58,93-94

EPRexperimentor"paradox,"180-83,216,239-40,248-49,250-51

ESP(extrasensoryperception),140,236,248-49

Esterman,I.,207

Everett,H.,241

F

Faber,R.,63

Feedback

explicationsof,65-69

informalcharacterizationof,63-65

reductionof,73-75

Feyerabend,P.,4,151

Feynman,R.,218

Fodor,J.,32,122-29,133

Forester,C.,145

Frisch,R.,207

Function

incyberneticmechanisms,89-98

ofreproductivesystem,110,118-20

symptomsof,100-102

G

Gardner,M.,164

Genes

dominanceamong,129

asmacromolecularentities,129-30

Genetics,58,124,129-31

Germer,L.,163,201

Glansdorff,P.,137

Goal

ofcyberneticmechanisms,58,61,75,76-98

ofselectionprocess,109-10,120

ultimate,ofcyberneticmechanism,88

Goalseeking

byfeedbackdevices,76-83

hierarchicallyordered,87

relativetocontext,83-87

Goosens,W.,130

Gould,S.,95

Grangier,P.,180,182

Green,M.,143-52

Greenler,R.,234n

H

Hamiltonianoperator,190-91,206

Heat-seekingmissile,81,85-87,97

Heisenberg,W.,159-60,177-78,192,194,203-5,214

Hellman,G.,164

Hempel,C.,93

Hiddenvariables,181-82,229

Hierarchicalorganizationoffeedbackloops,87-88

Holism,6,158,185,189-92

Homeostasis,59,83,116

Hull,D.,124,129

Huxley,A.,232-34

I

Indefinitenessofthepast,175-77,201-2.SeealsoMultiplicity;Potentiality;Quantalpossibility

Indeterminism,5-6

accordingtoJames,225

accordingtoPeirce,196,225

accordingtoPopper,194

quantummechanical,186,199

Instrumentalism,224,225-26,139

Intentions(conscious),55

Interactionbetweenmindandmatter,156,239-40

Interference

betweenminds,248

inparticlediffraction,161,167,212

Intrinsicproperties,reductionof,47-48

Irreversibility,173,211-14

J

James,W.,225

K

"Keeping"mechanism,88-89,105

L

Level(s)ofdescription,13-21

confusionof,16-21

defined,14

vs.scopeorrange,9,14

Lewontin,R.,95

Localityofcausalaction,13.SeealsoNonseparability

Logic

modal,ofpotentiality,163-67

quantum,164

Lucretius,4,5

M

Mackie,J.,105

McNulty,P.,19

Macromolecules,130

Manier,E.,60,63

Mathematics(asmarkofscientificknowledge),37-40

Measurement

irreversibilityof,213

problem,193

Measuringinstrument(defined),173

Mechanisticworldpicture,12-32

Meehl,P.,143

Mill,J.,6-7

Mind

asagentofactualization,194,221-26,139-55

partsof,244-45,253

asperformerofmentalactivities,155-56

Multiplicity(multiplepotentialities),171,180-83,201-2.SeealsoQuantalpossibility

Mysteryofbasicfacts,21,30,137,219-31

Mysticalexperiences,141,232,233,235

N

Nagel,E.,59,60,63,81,83

Naturalkind,30,93,123,125

Naturalselection

ofconsciousness,141,144-45

Darwin'smetaphorof,100,116

as"downwardcausation,"135-36

andfeedbackprocesses,105-7

andpurposiveselection,112-15

andteleologicaldescriptions,99-121

Newtoniandeterminism,136

Nissen,L.,60,71-74,81-82

Nonadditivity,186

Nonlocality,180-83,187-90

Nonseparability,187,189

O

Objectivity

ofprobabilityinquantummechanics,159,192

ofscientificattitudetowardnature,139,146,203-4,232-36

ofthetransitiontoactuality,193

Observer,173,204

Ontologicalcommitment

tocausalagents,140-43

criterionof,10

ofthequantumtheory,140-43

Operationism

indouble-slitexperiment,169

Huxley's,232-33

Otherminds,146,242

P

Pacificsalmon,geneticsurvivalin,104,109,118

Pancreas(asfeedbackregulator),97

Pangens(asmacromolecularentities),130

Part(s)

ofminds,155

reductionto,130

whole-partrelation,3-11

Patternsoforganization

causalefficacyof,4,26

reductionof,126,132-38

Pease,V.,19

Peirce,C.,168,196,225

Peres,A.,235

Physicalism

astheoryofmind,158

token,123-27

Plovers,dutchsizein,105-6

Podolsky,B.,172,180-82

Polanyi,M.,134-38

Popper,K.,10,134-38,193-203

Possibility

counterfactual(C-),167

objective,159,160,162

quantum-mechanical(Q-),171-72

real(R-),168

Potentiality

andactuality,criterionof,172-74

logicof,163-67

asobjectivefeatureofworld,165,167

asQ-possibility,171-72

Powers,W.,60,117

Prigogine,I.,137

Probability.SeealsoPossibility;Propensities

objective,159

subjective,214

Probabilityamplitude(definition),166

Propensities,195-96

Propernames,reductionof,47

Properties,reductionof

intrinsic,47-48,50

relational,48-49

Purpose,109,112,117,119-20

Putnam,H.,164,228

Q

Quantal(Q-)possibility,171-72

inSchroedinger'scatandinDavisson/Germerexperiments,199-203

Quine,W.,10

R

Rangeorscopeofdescription(distinguishedfromlevel),9,14

Real(R-)possibility,168-69

inPopper'spin-board,197-99,202

Realism.SeealsoObjectivity

indouble-slitexperiment,169-71

asguideforinquiry,228

inscienceandincommonsense,26-27

Reality,criterionof,172-73

Reduction,interlevel

ofabilities,49-54

ofentities,11

offunctionalcontexts,132

ofgeneralizationsaboutcontexts,131

ofintrinsicproperties,47-48

ofMendeliangenetics,57,130

oforganizationalpatterns(wiringdiagrams),132

ofpropernames,47

ofrelationalproperties,48-49,122-38

ofteleologicalconcepts,56-62

oftemperature,15,52,57,130

ofthermodynamics,31,57,74,130

Relationalproperties,reductionof,48-49,122-38

Reproductivestructures,nonfunctionalityof,118-20

Roger,G.,180,182

Rosen,N.,172,180-82

Rosenblueth,A.,59,63

Rousseau,J.,6,16,26

Ruse,M.,105-6

Ryle,G.,17,19,33-46

S

Salmon,Pacific,geneticsurvivalin,104,109,118

Schlegel,R.,215-16

Schroedinger,E.,159-60,177-78,194,225,141

Schroedinger'scatexperiment,177-79

andagreementamongobservers,240-42

complementedbyDavisson/Germer,209-10

modified,withnonconscioussubject,199-200

andself-referenceofthequantumtheory,235-36

Scientificobjectivity,45,139,146,232-36

Selection,natural

ofconsciousness,141,144-45

Darwin'smetaphor,100,116

as''downwardcausation,"135-36

notafeedbackprocess,105-7

notpurposive,112-15

andteleologicaldescriptions,99-121

Sensations

characteristicsof,149-52

complexityof,152-55

Shimony,A.,180,182,228

Smart,J.,147

Solipsism,146,236,242

Sorting,mere,108,112-15

Space-time,structureof,148,238-39,245-48

Statisticalmechanics,reductionofthermodynamicsto,57

Stern,O.,207

Survival

ofgenes,asultimategoalofnaturalselection,109,110,120

individual,asultimategoalofcyberneticmechanisms,88-89

individualvs.genetic,104,109,118

T

Taylor,R.,63

Temperature

reductionof,15,52,57,130

relationtocommonsenseconcepts,41-43

Theory-ladenterms,40-46

Thermodynamics

complexityin,223

irreversibilityin,173,211-14

reductionof,31,57,74,130

Thermostat,64,67,72,73,77,80,81,83,85,87,96-97

clockwork garden: on the mechanistic reduction of living things

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