What Shanl We Mam?

The Tragedy of the Commons

The population problem has no technical solution;it requires a fundamental extension in morality.

Garrett Hardin

At the end of a thoughtful article onthe future of nuclear war, Wiesner andYork (1) concluded that: "Both sides inthe arms race are ... confronted by thedilemma of steadily increasing militarypower and steadily decreasing nationalsecurity. It is our considered profes-sional judgment that this dilemma hasno technical solution. If the great pow-ers continue to look for solutions inthe area of science and technology only,the result will be to worsen the situa-tion."

I would like to focus your attentionnot on the subject of the article (na-tional security in a nuclear world) buton the kind of conclusion they reached,namely that there is no technical solu-tion to the problem. An implicit andalmost universal assumption of discus-sions published in professional andsemipopular scientific journals is thatthe problem under discussion has atechnical solution. A technical solutionmay be defined as one that requires achange only in. the techniques of thenatural sciences, demanding little ornothing in the way of change in humanvalues or ideas of morality.

In our day (though not in earliertimes) technical solutions are alwayswelcome. Because of previous failuresin prophecy, it takes courage to assertthat a desired technical solution is notpossible. Wiesner and York exhibitedthis courage; publishing in a sciencejournal, they insisted that the solutionto the problem was not to be found inthe natural sciences. They cautiouslyqualified their statement with thephrase, "It is our considered profes-

The author is professor of biology, Universityof California, Santa Barbara. This article isbased on a presidential address presented beforethe meeting of the Pacific Division of the Ameri-can Association for the Advancement of Scienceat Utah State University, Logan, 25 June 1968.

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sional judgment. . . ." Vhether theywere right or not is not the concern ofthe present article. Rather, the concernhere is with the important concept of aclass of human problems which can becalled "no technical solution problems,"and, more specifically, with the identifi-cation and discussion of one of these.

It is easy to show that the class is nota null class. Recall the game of tick-tack-toe. Consider the problem, "Howcan I win. the game of tick-tack-toe?"It is well known that I cannot, if I as-sume (in keeping with the conventionsof game theory) that my opponent un-derstands the game perfectly. Put an-other way, there is no "technical solu-tion" to the problem. I can win onlyby giving a radical meaning to the word"win." I can hit my opponent over thehead; or I can drug him; or I can falsifythe records. Every way in which I "win"involves, in some sense, an abandon-ment of the game, as we intuitively un-derstand it. (I can also, of course,openly abandon the game-refuse toplay it. This is what most adults do.)The class of "No technical solution

problems" has members. My thesis isthat the "population problem," as con-ventionally conceived, is a member ofthis class. How it is conventionally con-ceived needs some comment. It is fairto say that most people who' anguishover the population problem are tryingto find a way to avoid the evils of over-population without relinquishing any ofthe privileges they now enjoy. Theythink that farming the seas or develop-ing new strains of wheat will solve theproblem-technologically. I try to showhere that the solution they seek cannotbe found. The population problem can-not be solved in a technical way, anymore than can the problem of winningthe game of tick-tack-toe.

Population, as Malthus said, naturallytends to grow "geometrically," or, as wewould now say, exponentially. In afinite world this means that the percapita share of the world's goods muststeadily decrease. Is ours a finite world?A fair defense can be put forward for

the view that the world is infinite; orthat we do not know that it is not. But,in terms of the practical problems thatwe must face in the next few genera-tions with the foreseeable technology, itis clear that we will greatly increasehuman misery if we do not, during theimmediate future, assume that the worldavailable to the terrestrial human pop-ulation is finite. "Space" is no escape(2).A finite world can support only a

finite population; therefore, populationgrowth must eventually equal zero. (Thecase of perpetual wide fluctuationsabove and below zero is a trivial variantthat need not be discussed.) When thiscondition is met, what will be the situa-tion of mankind? Specifically, can Ben-tham's goal of "the greatest good forthe greatest number" be realized?No-for two reasons, each sufficient

by itself. The first is a theoretical one.It is not mathematically possible tomaximize for two (or more) variables atthe same time. This was clearly statedby von Neumann and Morgenstern (3),but the principle is implicit in the theoryof partial differential equations, datingback at least to D'Alembert (1717-1783).The second reason springs directly

from biological facts. To live, anyorganism must have a source of energy(for example, food). This energy isutilized for two puposes: mere main-tenance and work. For man, mainte-nance of life requires about 1600 kilo-calories a day ("maintenance calories').Anything that he does over and abovemerely staying alive will be defined aswork, and is supported by "work cal-ories" which he takes in. Work caloriesare used not only for what we call workin common speech; they are also re-quired for all forms of enjoyment, fromswimming and automobile racing toplaying music and writing poetry. Ifour goal is to maximize population it isobvious what we must do: We mustmake the work calories per person ap-proach as close to zero as possible. Nogourmet meals, no vacations, no sports,no music, no literature, no art. . . . Ithink that everyone will grant, without

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argument or proof, that maximizingpopulation does not max2imize goods.Bentham's goal is impossible.

In reaching this conclusion I havemade the usual assumption that it isthe acquisition of energy that is theproblem. The appearance of atomicenergy has led some to question thisassumption. However, given an infinitesource of energy, population growthstill produces an inescapable problem.The problem of the acquisition of en-ergy is replaced by the problem of itsdissipation, as J. H. Fremlin has so wit-tily shown (4). The arithmetic signs in-t-he analysis are, as it were, reversed;but Bentham's goal is still unobtainable.The optimum population is, then, less

than the maximum. The difficulty ofdefining the optimum is enormous; sofar as I know, no one has seriouslytackled this problem. Reaching an ac-ceptable and stable solution will surelyrequire more than one generation ofhard analytical work-and much per-suasion.We want the maximum good per

person; but what is good? To one per-son it is wilderness, to another it is skilodges for thousands. To one it is estu-aries to nourish ducks for hunters toshoot; to another it is factory land.Comparing one good with another is,we usually say, impossible becausegoods are incommensurable. Incommen-surables cannot be compared.

Theoretically this may be true; but inreal life incommensurables are commen-surable. Only a criterion of judgmentand a system of weighting are needed.In nature the criterion is survival. Is itbetter for a species to be small and hide-able, or large and powerful? Naturalselection commensurates the incommen-surables. The compromise achieved de-pends on a natural weighting of thevalues of the variables.Man must imitate this process. There

is no doubt that in fact he already does,but unconsciously. It is when the hiddendecisions are made explicit that thearguments begin. The problem for theyears ahead is to work out an accept-able theory of weighting. Synergisticeffects, nonlinear variation, and difficul-ties in discounting the future make theintellectual problem difficult, but not(in principle) insoluble.Has any cultural group solved this

practical problem at the present time,even on an intuitive level? One simplefact proves that none has: there is noprosperous population in the world to-day that has, and has had for some

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time,-p - rate of zero. Any peoplethat has intuitively identified its opti-mum point will soon reach it, afterwhich its growth rate becomes and re-mains zero.Of course, a positive growth rate

might be taken as evidence that a pop-ulation is below its optimum. However,by any reasonable standards, the mostrapidly growing populations on earthtoday are (in general) the most misera-ble. This association (which need not beinvariable) casts doubt on the optimisticassumption that the positive growth rateof a population is evidence that it hasyet to reach its optimum.We can make little progress in work-

ing toward optimum poulation size untilwe explicitly exorcize the spirit ofAdam Smith in the field of practicaldemography. In economic affairs, TheWealth of Nations (1776) popularizedthe "invisible hand," the idea that anindividual who "intends only his owngain," is, as it were, "led by an invisiblehand to promote . .,. the public interest"(5). Adam Smith did not assert thatthis was invariably true, and perhapsneither did any of his followers. But hecontributed to a dominant tendency ofthought that has ever since interferedwith positive action based on rationalanalysis, namely, the tendency to as-sume that decisions reached individuallywill, in fact, be the best decisions for anentire society. If this assumption iscorrect it justifies the continuance ofour present policy of laissez-faire inreproduction. If it is correct we can as-sume that men will control their individ-ual fecundity so as to produce the opti-mum population. If the assumption isnot correct, we need to reexamine ourindividual freedoms to see which onesare defensible.

Tragedy of Freedom in a Commons

The rebuttal to the invisible hand inpopulation control is to be found in ascenario first sketched in a little-knownpamphlet (6) in 1833 by a mathematicalamateur named William Forster Lloyd(1794-1852). We may well call it "thetragedy of the commons," using theword "tragedy" as the philosopherWhitehead used it (7): "The essence ofdramatic tragedy is not unhappiness. Itresides in the solemnity of the remorse-less working of things." He then' goes on.to say, "This inevitableness of destinycan only be illustrated in terms of hu-man life by incidents which in fact in-

volve unhappiness. For it is only bythem that the futility of escape can bemade evident in the drama."The tragedy of the commons develops

in this way. Picture a pasture open toall. It is to be expected that each herds-man will try to keep as many cattle aspossible on the commons. Such an ar-rangement may work reasonably satis-factorily for centuries because tribalwars, poaching, and disease keep thenumbers of both man and beast wellbelow the carrying capacity of the land.Finally, however, comes the day ofreckoning, that is, the day when thelong-desired goal of social stability be-comes a reality. At this point, the in-herent logic of the commons remorse-lessly generates tragedy.As a rational being, each herdsman

seeks to maximize his gain. Explicitlyor implicitly, more or less consciously,he asks, "What is the utility to me ofadding one more animal to my herd?"This utility has one negative and onepositive component.

1) The positive component is a func-tion of the increment of one animal.Since the herdsman receives all theproceeds from the sale of the additionalanimal, the positive utility is nearly +1.

2) The negative component is a func-tion of the additional overgrazingcreated by one more animal. Since,however, the effects of overgrazing areshared by all the herdsmen, the negativeutility for any particular decision-making herdsman is only a fraction of-1.Adding together the component par-

tial utilities, the rational herdsmanconcludes that the only sensible coursefor him to pursue is to add anotheranimal to his herd. And another; andanother.... But this is the conclusionreached by each and every rationalherdsman sharing a commons. Thereinis the tragedy. Each man is locked intoa system that compels him to increasehis herd without limit-in a world thatis limited. Ruin is the destination to-ward which all men rush, each pursuinghis own best interest in a society thatbelieves in the freedom of the com-mons. Freedom in a commons bringsruin to all.Some would say that this is a plati-

tude. Would that it were! In a sense, itwas learned thousands of years ago, butnatural selection favors the forces ofpsychological denial (8). The individualbenefits as an individual from his abilityto deny the truth even though society asa whole, of which he is a part, suffers.

SCIENCE, VOL. 162

Education can counteract the naturaltendency to do the wrong thing, but theinexorable succession of generationsrequires that the basis for this knowl-edge be constantly refreshed.A simple incident that occurred a few

years ago in Leominster, Massachusetts,shows how perishable the knowledge is.During the Christmas shopping seasonthe parking meters downtown werecovered with plastic bags that bore tagsreading: "Do not open until after Christ-mas. Free parking courtesy of themayor and city council." In other words,facing the prospect of an increased de-mand for already scarce space, the cityfathers reinstituted the system of thecommons. (Cynically, we suspect thatthey gained more votes than they lostby this retrogressive act.)

In an approximate way, the logic ofthe commons has been understood fora long time, perhaps since the dis-covery of agriculture or the inventionof private property in real estate. Butit is understood mostly only in specialcases which are not sufficiently general-ized. Even at this late date, cattlemenleasing national land on the westernranges demonstrate no more than anambivalent understanding, in constantlypressuring federal authorities to increasethe head count to the point where over-grazing produces erosion and weed-dominance. Likewise, the oceans of theworld continue to suffer from the sur-vival of the philosophy of the commons.Maritime nations still respond automat-ically to the shibboleth of the "freedomof the seas." Professing to believe inthe "inexhaustible resources of theoceans," they bring species after speciesof fish and whales closer to extinction(9).The National Parks present another

instance of the working out of thetragedy of the commons. At present,they are open to all, without limit. Theparks themselves are limited in extent-there is only one Yosemite Valley-whereas population seems to grow with-out limit. The values that visitors seekin the parks are steadily eroded. Plainly,we must soon cease to treat the parksas commons or they will be of no valueto anyone.What shall we do? We have several

options. We might sell them off as pri-vate property. We might keep them aspublic property, but allocate the rightto enter them. The allocation might beon the basis of wealth, by the use of anauction system. It might be on the basisof merit, as defined by some agreed-13 DECEMBER 1968

upon standards. It might be by lottery.Or it might be on a first-come, first-served basis, administered to longqueues. These, I think, are all thereasonable possibilities. They are allobjectionable. But we must choose-oracquiesce in the destruction of the com-mons that we call our National Parks.

Pollution

In a reverse way, the tragedy ofthe commons reappears in problems ofpollution. Here it is not a question oftaking something out of the commons,but of putting something in-sewage,or chemical, radioactive, and heatwastes into water; noxious and danger-ous fumes into the air; and distractingand unpleasant advertising signs intothe line of sight. The calculations ofutility are much the same as before.The rational man finds that his share ofthe cost of the wastes he discharges intothe commons is less than the cost ofpurifying his wastes before releasingthem. Since this is true for everyone, weare locked into a system of "fouling ourown nest," so long as we behave onlyas independent, rational, free-enter-prisers.The tragedy of the commons as a

food basket is averted by private prop-erty, or something formally like it. Butthe air and waters surrounding us can-not readily be fenced, and so the trag-edy of the commons as a cesspool mustbe prevented by different means, by co-ercive laws or taxing devices that makeit cheaper for the polluter to treat hispollutants than to discharge them un-treated. We have not progressed as farwith the solution of this problem as wehave with the first. Indeed, our particu-lar concept of private property, whichdeters us from exhausting the positiveresources of the earth, favors pollution.The owner of a factory on the bank ofa stream-whose property extends tothe middle of the stream-often hasdifficulty seeing why it is not his naturalright to muddy the waters flowing pasthis door. The law, always behind thetimes, requires elaborate stitching andfitting to adapt it to this newly perceivedaspect of the commons.The pollution problem is a con-

sequence of population. It did not muchmatter how a lonely American frontiers-man disposed of his waste. "Flowingwater purifies itself every 10 miles," mygrandfather used to say, and the mythwas near enough to the truth when he

was a boy, for there were not too manypeople. But as population became denser,the natural chemical and biological re-cycling processes became overloaded,calling for a redefinition of propertyrights.

How To Legislate Temperance?

Analysis of the pollution problem asa function of population density un-covers a not generally recognized prin-ciple of morality, namely: the moralityof an act is a function of the state ofthe system at the time it is performed(10). Using the commons as a cesspooldoes not harm the general public underfrontier conditions, because there is nopublic; the same behavior in a metropo-lis is unbearable. A hundred and fiftyyears ago a plainsman could kill anAmerican bison, cut out only the tonguefor his dinner, and discard the rest ofthe animal. He was not in any impor-tant sense being wasteful. Today, withonly a few thousand bison left, wewould be appalled at such behavior.

In passing, it is worth noting that themorality of an act cannot be determinedfrom a photograph. One does not knowwhether a man killing an elephant orsetting flre to the grassland is harmingothers until one knows the total systemin which his act appears. "One pictureis worth a thousand words," said anancient Chinese; but it may take 10,000words to validate it. It is as tempting toecologists as it is to reformers in generalto try to persuade others by way of thephotographic shortcut. But the essenseof an argument cannot be photo-graphed: it must be presented rationally-in words.

That morality is system-sensitiveescaped the attention of most codifiersof ethics in the past. "Thou shaltnot . . ." is the form of traditionalethical directives which make no allow-ance for particular circumstances. Thelaws of our society follow the pattern ofancient ethics, and therefore are poorlysuited to governing a complex, crowded,changeable world. Our epicyclic solu-tion is to augment statutory law withadministrative law. Since it is practicallyimpossible to spell out all the conditionsunder which it is safe to burn trash inthe back yard or to run an automobilewithout smog-control, by law we dele-gate the details to bureaus. The resultis administrative law, which is rightlyfeared for an ancient reason-Quiscustodiet ipsos custodes?-"Who shall

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watch the watchers themselves?" JohnAdams said that we must have "a gov-ernment of laws and not men." Bureauadministrators, trying to evaluate themorality of acts in the total system, aresingularly liable to corruption, produc-ing a government by men, not laws.

Prohibition is easy to legislate(though not necessarily to enforce); buthow do we legislate temperance? Ex-perience indicates that it can be ac-complished best through the mediationof administrative law. We limit possi-bilities unnecessarily if we suppose thatthe sentiment of Quis custodiet deniesus the use of administrative law. Weshould rather retain the phrase as aperpetual reminder of fearful dangerswe cannot avoid. The great challengefacing us now is to invent the correctivefeedbacks that are needed to keep cus-todians honest. We must find ways tolegitimate the needed authority of boththe custodians and the corrective feed-backs.

Freedom To Breed Is Intolerable

The tragedy of the commons is in-volved in population problems in an-other way. In a world governed solelyby the principle of "dog eat dog"-ifindeed there ever was such a world-how many children a family had wouldnot be a matter of public concern.Parents who bred too exuberantly wouldleave fewer descendants, not more, be-cause they would be unable to careadequately for their children. DavidLack and others have found that such anegative feedback demonstrably con-trols the fecundity of birds (11). Butmen are not birds, and have not actedlike them for millenniums, at least.

If each human family were depen-dent only on its own resources; if thechildren of improvident parents starvedto death; if, thus, overbreeding broughtits own "punishment" to the germ line-then there would be no public interestin controlling the breeding of families.But our society is deeply committed tothe welfare state (12), and hence isconfronted with another aspect of thetragedy of the commons.

In a welfare state, how shall we dealwith the family, the religion, the race,or the class (or indeed any distinguish-able and cohesive group) that adoptsoverbreeding as a policy to secure itsown aggrandizement (13)? To couplethe concept of freedom to breed withthe belief that everyone born has an

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equal right to the commons is to lockthe world into a tragic course of action.

Unfortunately this is just the courseof action that is being pursued by theUnited Nations. In late 1967, some 30nations agreed to the following (14):The Universal Declaration of Human

Rights describes the family as the naturaland fundamental unit of society. It fol-lows that any choice and decision withregard to the size of the family must irte-vocably rest with the family itself, andcannot be made by anyone else.

It is painful to have to deny categor-ically the validity of this right; denyingit, one feels as uncomfortable as a resi-dent of Salem, Massachusetts, whodenied the reality of witches in the 17thcentury. At the present time, in liberalquarters, something like a taboo acts toinhibit criticism of the United Nations.There is a feeling that the UnitedNations is "our last and best hope,"that we shouldn't find fault with it; weshouldn't play into the hands of thearchconservatives. However, let us notforget what Robert Louis Stevensonsaid: "The truth that is suppressed byfriends is the readiest weapon of theenemy." If we love the truth we mustopenly deny the validity of the UniversalDeclaration of Human Rights, eventhough it is promoted by the UnitedNations. We should also join withKingsley Davis (15) in attempting toget Planned Parenthood-World Popula-tion to see the error of its ways in em-bracing the same tragic ideal.

Conscience Is Self-Eliminating

It is a mistake to think that we cancontrol the breeding of mankind in thelong run by an appeal to conscience.Charles Galton Darwin made this pointwhen he spoke on the centennial of thepublication of his grandfather's greatbook. The argument is straightforwardand Darwinian.

People vary. Confronted with appealsto limit breeding, some people will un-doubtedly respond to the plea morethan others. Those who have morechildren will produce a larger fractionof the next generation than those withmore susceptible consciences. The dif-ference will be accentuated, generationby generation.

In C. G. Darwin's words: "It maywell be that it would take hundreds ofgenerations for the progenitive instinctto develop in this way, but if it shoulddo so, nature would have taken herrevenge, and the variety Homo contra-

cipiens would become extinct andwould be replaced by the variety Homoprogenitivus" (16).The argument assumes that con-

science or the desire for children (nomatter which) is hereditary-but heredi-tary only in the most general formalsense. The result will be the samewhether the attitude is transmittedthrough germ cells, or exosomatically,to use A. J. Lotka's term. (If one deniesthe latter possibility as well as theformer, then what's the point of educa-tion?) The argument has here beenstated in the context of the populationproblem, but it applies equally well toany instance in which society appealsto an individual exploiting a commonsto restrain himself for the generalgood-by means of his conscience. Tomake such an appeal is to set up aselective system that works toward theelimination of conscience from the race.

Pathogenic Effects of Conscience

The long-term disadvantage of anappeal to conscience should be enoughto condemn it; but has serious short-term disadvantages as well. If we aska man who is exploiting a commons todesist "in the name of conscience,"what are we saying to him? What doeshe hear?-not only at the moment butalso in the wee small hours of thenight when, half asleep, he remembersnot merely the words we used but alsothe nonverbal communication cues wegave him unawares? Sooner or later,consciously or subconsciously, he sensesthat he has received two communica-tions, and that they are contradictory:(i) (intended communication) "If youdon't do as we ask, we will openly con-demn you for not acting like a respon-sible citizen"; (ii) (the unintendedcommunication) "If you do behave aswe ask, we will secretly condemr. youfor a simpleton who can be shamedinto standing aside while the rest of usexploit the commons."

Everyman then is caught in whatBateson has called a "double bind."Bateson and his co-workers have madea plausible case for viewing the doublebind as an important causative factor inthe genesis of schizophrenia (17). Thedouble bind may not always be sodamaging, but it always endangers themental health of anyone to whom it isapplied. "A bad conscience," saidNietzsche, "is a kind of illness."To conjure up a conscience in others

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is tempting to anyone who wishes toextend his control beyond the legallimits. Leaders at the highest levelsuccumb to this temptation. Has anyPresident during the past generationfailed to call on labor unions to moder-ate voluntarily their demands for higherwages, or to steel companies to honorvoluntary guidelines on prices? I canrecall none. The rhetoric used on suchoccasions is designed to produce feel-ings of guilt in noncooperators.For centuries it was assumed without

proof that guilt was a valuable, perhapseven an indispensable, ingredient of thecivilized life. Now, in this post-Freudianworld, we doubt it.

Paul Goodman speaks from themodern point of view when he says:"No good has ever come from feelingguilty, neither intelligence, policy, norcompassion. The guilty do not payattention to the object but only to them-selves, and not even to their own in-terests, which might make sense, but totheir anxieties" (18).One does not have to be a profes-

sional psychiatrist to see the conse-quences of anxiety. We in the Westernworld are just emerging from a dreadfultwo-centuries-long Dark Ages of Erosthat was sustained partly by prohibi-tion laws, but perhaps more effectivelyby the anxiety-generating mechanismsof education. Alex Comfort has told thestory well in The Anxiety Makers (19);it is not a pretty one.

Since proof is difficult, we may evenconcede that the results of anxiety maysometimes, from certain points of view,be desirable. The larger question weshould ask is whether, as a matter ofpolicy, we should ever encourage theuse of a technique the tendency (if notthe intention) of which is psycholog-ically pathogenic. We hear much talkthese days of responsible parenthood;the coupled words are incorporatedinto the titles of some organizations de-voted to birth control. Some peoplehave proposed massive propagandacampaigns to instill responsibility intothe nation's (or the world's) breeders.But what is the meaning of the wordresponsibility in this context? Is it notmerely a synonym for the word con-science? When we use the word re-sponsibility in the absence of substantialsanctions are we not trying to browbeata free man in a commons into actingagainst his own interest? Responsibilityis a verbal counterfeit for a substantialquid pro quo. It is an attempt to getsomething for nothing.13 DECEMBER 1968

If the word responsibility is to beused at all, I suggest that it be in thesense Charles Frankel uses it (20)."Responsibility," says this philosopher,"is the product of definite social ar-rangements." Notice that Frankel callsfor social arrangements-not propa-ganda.

Mutual Coercion

Mutually Agreed upon

The social arrangements that produceresponsibility are arrangements thatcreate coercion, of some sort. Consid-er bank-robbing. The man who takesmoney from a bank acts as if the bankwere a commons. How do we preventsuch action? Certainly not by trying tocontrol his behavior solely by a verbalappeal to his sense of responsibility.Rather than rely on propaganda wefollow Frankel's lead and insist that abank is not a commons; we seek thedefinite social arrangements that willkeep it from becoming a commons.That we thereby infringe on the free-dom of would-be robbers we neitherdeny nor regret.The morality of bank-robbing is

particularly easy to understand becausewe accept complete prohibition of thisactivity. We are willing to say "Thoushalt not rob banks," without providingfor exceptions. But temperance also canbe created by coercion. Taxing is a goodcoercive device. To keep downtownshoppers temperate in their use ofparking space we introduce parkingmeters for short periods, and trafficfines for longer ones. We need notactually forbid a citizen to park as longas he wants to; we need merely make itincreasingly expensive for him to do so.Not prohibition, but carefully biasedoptions are what we offer him. A Madi-son Avenue man might call this per-suasion; I prefer the greater candor ofthe word coercion.

Coercion is a dirty word to mostliberals now, but it need not forever beso. As with the four-letter words, itsdirtiness can be cleansed away by ex-posure to the light, by saying it over andover without apology or embarrassment.To many, the word coercion impliesarbitrary decisions of distant and irre-sponsible bureaucrats; but this is not anecessary part of its meaning. The onlykind of coercion I recommend is mutualcoercion, mutually agreed upon by themajority of the people affected.To say that we mutually agree to

coercion is not to say that we are re-quired to enjoy it, or even to pretendwe enjoy it. Who enjoys taxes? We allgrumble about them. But we acceptcompulsory taxes because we recognizethat voluntary taxes would favor theconscienceless. We institute and (grum-blingly) support taxes and other coercivedevices to escape the horror of thecommons.An alternative to the commons need

not be perfectly just to be preferable.With real estate and other materialgoods, the alternative we have chosenis the institution of private propertycoupled with legal inheritance. Is thissystem perfectly just? As a geneticallytrained biologist I deny that it is. Itseems to me that, if there are to be dif-ferences in individual inheritance, legalpossession should be perfectly cor-related with biological inheritance-thatthose who are biologically more fit tobe the custodians of property and powershould legally inherit more. But geneticrecombination continually makes a

mockery of the doctrine of "like father,like son" implicit in our laws of legal in-heritance. An idiot can inherit millions,and a trust fund can keep his estateintact. We must admit that our legalsystem of private property plus inheri-tance is unjust-but we put up with itbecause we are not convinced, at themoment, that anyone has invented abetter system. The alternative of thecommons is too horrifying to contem-plate. Injustice is preferable to totalruin.

It is one of the peculiarities of thewarfare between reform and the statusquo that it is thoughtlessly governedby a double standard. Whenever a re-form measure is proposed it is oftendefeated when its opponents trium-phantly discover a flaw in it. As Kings-ley Davis has pointed out (21), worship-pers of the status quo sometimes implythat no reform is possible without unan-imous agreement, an implication con-trary to historical fact. As nearly as Ican make out, automatic rejection ofproposed reforms is based on one oftwo unconscious assumptions: (i) thatthe status quo is perfect; or (ii) that thechoice we face is between reform andno action; if the proposed reform isimperfect, we presumably should takeno action at all, while we wait for aperfect proposal.

But we can never do nothing. Thatwhich we have done for thousands ofyears is also action. It also producesevils. Once we are aware that the

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status quo is action, we can then com-pare its discoverable advantages anddisadvantages with the predicted ad-vantages and disadvantages of the pro-posed reform, discounting as best wecan for our lack of experience. On thebasis of such a comparison, we canmake a rational decision which will notinvolve the unworkable assumption thatonly perfect systems are tolerable.

Recognition of Necessity

Perhaps the simplest summary of thisanalysis of man's population problemsis this: the commons, if justifiable atall, is justifiable only under conditionsof low-population density. As the hu-man population has increased, thecommons has had to be abandoned inone aspect after another.

First we abandoned the commons infood gathering, enclosing farm landand restricting pastures and huntingand fishing areas. These restrictionsare still not complete throughout theworld.Somewhat later we saw that the com-

mons as a place for waste disposalwould also have to be abandoned. Re-strictions on the disposal of domesticsewage are widely accepted in theWestern world; we are still strugglingto close the commons to pollution byautomobiles, factories, insecticidesprayers, fertilizing operations, andatomic energy installations.

In a still more embryonic state is ourrecognition of the evils of the commonsin matters of pleasure. There is almostno restriction on the propagation ofsound waves in the public medium. Theshopping public is assaulted with mind-less music, without its consent. Our

government is paying out billions ofdollars to create supersonic transportwhich will disturb 50,000 people forevery one person who is whisked fromcoast to coast 3 hours faster. Adver-tisers muddy the airwaves of radio andtelevision and pollute the view oftravelers. We are a long way from out-lawing the commons in matters ofpleasure. Is this because our Puritaninheritance makes us view pleasure assomething of a sin, and pain (that is,the pollution of advertising) as the signof virtue?

Every new enclosure of the com-mons involves the infringement ofsomebody's personal liberty. Infringe-ments made in the distant past are ac-cepted because no contemporary com-plains of a loss. It is the newly pro-posed infringements that we vigorouslyoppose; cries of "rights" and "freedom"fill the air. But what does "freedom"mean? When men mutually agreed topass laws against robbing, mankind be-came more free, not less so. Individualslocked into the logic of the commonsare free only to bring on universal ruin;once they see the necessity of mutualcoercion, they become free to pursueother goals. I believe it was Hegel whosaid, "Freedom is the recognition ofnecessity."The most important aspect of neces-

sity that we must now recognize, is thenecessity of abandoning the commonsin breeding. No technical solution canrescue us from the misery of overpopu-lation. Freedom to breed will bringruin to all. At the moment, to avoidhard decisions many of us are temptedto propagandize for conscience andresponsible parenthood. The tempta-tion must be resisted, because an ap-peal to independently acting con-

sciences selects for the disappearanceof all conscience in the long run, andanin,crease in anxiety in the short.The only way we can preserve and

nurture other and more precious free-doms is by relinquishing the freedomto breed, and that very soon. "Freedomis the recognition of necessity"-and itis the role of education to reveal to allthe necessity of abandoning the free-dom to breed. Only so, can we put anend to this aspect of the tragedy of thecommons.

References

1. J. B. Wiesner and H. F. York, Sci. Amer.211 (No. 4), 27 (1964).

2. G. Hardin, J. Hered. 50, 68 (1959); S. vonHoernor, Science 137, 18 (1962).

3. J. von Neumann and 0. Morgenstern, Theoryof Games and Economic Behavior (PrincetonUniv. Press, Princeton, N.J., 1947), p. 11.

4. J. H. Fremlin, New Sci., No. 415 (1964), p. 285.5. A. Smith, The Wealth of Nations (Modem

Library, New York, 1937), p. 423.6. W. F. Lloyd, Two Lectures on the Checks to

Population (Oxford Univ. Press, Oxford, Eng-land, 1833), reprinted (in part> in Population,Evolution, and Birth Control, G. Hardin,Ed. (Freeman, San Francisco, 1964), p. 37.

7. A. N. Whitehead, Science and the ModernWorld (Mentor, New York, 1948), p. 17.

8. G. Hardin, Ed. Population, Evolution, andBirth Control (Freeman, San Francisco, 1964),p. 56.

9. S. McVay, Sci. Amer. 216 (No. 8>, 13 (1966).10. J. Fletcher, Situation Ethics (Westminster,

Philadelphia, 1966).11. D. Lack, The Natural Regulation of Animal

Nuimbers (Clarendon Press, Oxford, 1954).12. H. Girvetz, From Wealth to Welfare (Stan-

ford Univ. Press, Stanford, Calif., 1950).13. G. Hardin, Perspec. Biol. Med. 6, 366 (1963).14. U. Thant, Int. Planned Parenthood News, No.

168 (February 1968>, p. 3.15. K. Davis, Science 158, 730 (1967).16. S. Tax, Ed., Evolution after Darwin (Univ.

of Chicago Press, Chicago, 1960), vol. 2, p.469.

17. G. Bateson, D. D. Jackson, J. Haley, J. Weak-land, Behav. Scd. 1, 251 (1956).

18. P. Goodman, New York Rev. Books 10(8),22 (23 May 1968).

19. A. Comfort, The Anxiety Makers (Nelson,London, 1967).

20. C. Frankel, The Case for Modern Man (Har-per, New York, 1955), p. 203.

21. J. D. Roslansky, Genetics and the Future ofMan (Appleton-Century-Crofts, New York,1966), p. 177.

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