sortal predicates and confirmation

Sortal Predicates and ConfirmationAuthor(s): Robert AckermannSource: Philosophical Studies: An International Journal for Philosophy in the AnalyticTradition, Vol. 20, No. 1/2 (Jan. - Feb., 1969), pp. 1-4Published by: SpringerStable URL: http://www.jstor.org/stable/4318610 .

Accessed: 24/06/2014 21:25

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected].

.

Springer is collaborating with JSTOR to digitize, preserve and extend access to Philosophical Studies: AnInternational Journal for Philosophy in the Analytic Tradition.

http://www.jstor.org

This content downloaded from 62.122.73.250 on Tue, 24 Jun 2014 21:25:36 PMAll use subject to JSTOR Terms and Conditions

http://www.jstor.org/action/showPublisher?publisherCode=springer

http://www.jstor.org/stable/4318610?origin=JSTOR-pdf

http://www.jstor.org/page/info/about/policies/terms.jsp


STlUDIES

Edited by WILFRID SELLARS and HERBERT FEIGL with the advice and assistance of PAUL MEEHL, JOHN HOSPERS, MAY BRODBECK

VOLUME XX Contents January-February 1969 NUMBERS 1-2

Sortal Predicates and Confirmation by Robert Ackermann, WASHINGTON UNIVERSITY

Partially Transparent Senses of Knowing by Jaakko Hintikka, UNIVERSITY OF HELSINKI and STANFORD

Wanting and Willing by James Rachels, UNIVERSITY OF RICHMOND

Policing the Aufbau by David K. Lewis, UNIVERSITY OF CALIFORNIA AT LOS ANGELES

On Reduction by Herbert E. Hendry, MICHIGAN STATE UNIVERSITY

Wittgenstein on Sensations by George B. Thomas, UNIVERSITY OF VIRGINIA

Other Times, Other Places, Other Minds by Irving Thalberg, UNIVERSITY OF ILLINOIS AT CHICAGO CIRCLE

A Rationale for Analogical Inference by Hugues Leblanc, TEMPLE UNIVERSITY

Sortal Predicates and Confirmation

by ROBERT ACKERMANN

WASHINGTON UNIVERSITY

A LOOSE but pervasive recognition of the importance of substantival general terms or sortal predicates has become increasingly prominent in recent philosophy. In particular many philosophers have felt that a clear notion

I



2 PHILOSOPHICAL STUDIES

of sortal predicates would have an intimate relationship to adequate ac- counts of the role of key terms (such as lawlike) in the philosophy of science. It seems that at least some such relationships are obvious from con- sensus remarks about sortal predicates, and I would like to highlight one of these relationships in this note which seems to have important but hitherto unremarked consequences for the notion of lawlikeness.

John Wallace has recently summarized some of the distinguishing char- acteristics of sortal predicates in a brief article discussing Geach's Reference and Generality, a book in which important points can be traced to the roughly equivalent notion of substantival general terms.' Perhaps most important, a sortal predicate can only be used clearly when one can count the number of objects to which the predicate applies in an appropriate space, or at least make clear sense of the claim that so many objects to which the predicate applies are present in the space. Typically, when a sortal predicate applies to an object, the object cannot be divided so as to obtain two objects such that the predicate then applies to both of them. Of course such notions can be traced back at least as far as the doctrine of substance in Aris- totle, and they become obscure when confronted with certain kinds of ob- jections. But it is not clear that this obscurity prevents us from recognizing sortals, at least in clear everyday cases, or from making use of the notion of sortal predicates for purposes in the philosophy of science.

Suppose, for example, we accept the typical fiction that scientific laws have the form 'All A's are B's,' or (x) (Ax D Bx).' Would it make sense to require that the antecedent predicate of such a form must also be a sortal predicate in any instance of a scientific law? The moment this is asked, it seems clear that many actual occurrences of scientific laws of roughly this form considered by scientists in practice (and not proposed by philosophers from considerations of logic) are such that the antecedent predicate is a sortal, i.e., it applies to objects which can be counted, and which are in some sense not divisible into more objects of the same kind within the appropriate theoretical framework. Difficulties with this idea cannot be de- nied. The first set of such difficulties arises with so-called mass terms. For example, various gas laws may seem inconsistent with the principle. A volume of oxygen gas may be divided into two smaller volumes of oxygen gas whiclh instantiate the same gas laws. Here one would need to turn to subtle considerations to save the hypothesis. Perhaps it can be made out that gas laws are about gases, and oxygen is merely one of the gases to which a given law might apply. Having established it conclusively for some sample of oxygen, that takes care of the claim (and confirmation) for that gas, since other samples of oxygen would be the same in every relevant respect according to the appropriate theory, so that a counterexample causing revision of the



SORTAL PREDICATES AND CONFIRMATION 3

claim would put the earlier observation in doubt. Further, it is not at all clear that a putative law about oxygen (as a gas) can be of the form '(x) (Ax DBx).' It could hardly begin 'All oxygens . . .' or 'All samples of oxygen . . .' or 'All molecules of oxygen . . .' but more likely in the fash- ion 'Oxygen . . .' Deeper difficulties for the suggestion involving sortal predicates which are raised by radioactive elements and field theories may also be circumvented by denying that '(x) (Ax D Bx)' will do as a general form for scientific laws. I don't wish to argue this here: I do wish to argue that the examples in the philosophical literature of putative scientific laws with the requisite form may usefully be compared with the claim that their antecedent predicates in actual instances of laws must be sortal predicates.

Consider the venerable 'All ravens are black.' Raven is a sortal. By all theories of confirmation, observations of black ravens will confirm the hypothesis, and observations of new black ravens will increase (no matter how slightly) the confirmation of the hypothesis. Observations of black ravens can be counted because ravens can be counted, and we can suppose that if ravens are tagged in some way, the mistake of counting a raven twice may be avoided. Let us take confirmation to be tied to sortals by the simple claim that the only observations that count (in confirmation) are observations that can be counted. Now consider the hypothesis which logic pro- vides as equivalent: All non-black things are non-ravens. Now non-black thing is clearly not a sortal, and many philosophers have observed that one cannot speak of the number of non-black things in some space. The conse- quent contention is that this hypothesis cannot be confirmed because non- black thing is not a sortal, and confirming instances that count cannot be counted. Suppose, for example, that a blank sheet of white paper is taken as a confirming instance. (We could take this journal page, since it is not black, but the black in it may cause concern for some possible divisions of the page.) Fine, let it be tagged. Suppose the tag is attached to the bottom half. Let the page (unknown to us) be cut in half. Now the untagged top half is still a non-black non-raven, but we can't count observation of it as increasing the confirmation of the hypothesis. It is a difficulty analogous to this one that raises confirmation problems for any hypothesis of the form under scrutiny with a non-sortal antecedent predicate. If we take the oc- currence of sortals seriously, we can eliminate the problems by striking out the confirmation of a hypothesis with a non-sortal antecedent in any case.

The suggestion that sortals be taken account of in this way seems to me to do no violence to scientific practice, although it does run counter to certain philosophical theories about confirmation. For example any theory of confirmation which accepts the equivalence condition which holds that if one of a pair of logically equivalent statements is a hypothesis, the other is



4 PHILOSOPHICAL STUDIES

a statement of the same hypothesis, and also accepts distinct positive instances of any hypothesis as confirming that hypothesis, must encounter the familiar paradox of confirmation. In terms of the raven hypothesis, such theories of confirmation yield the conclusion that a non-black non-raven, in being a (confirming) positive instance of 'All non-black things are non-ravens,' is also a confirming instance of the logically equivalent 'All ravens are black.'2 But if our claim involving sortals is correct, the former hypothesis is not confirmable, and not lawlike, and the paradox disappears. This conclusion by no means automatically supports theories of confirmation in which the paradox does not arise. For example, Goodman's remarks on confirmation in Fact, Fiction, and Forecast do not yield the confirmation paradox because he does not accept the equivalence condition.8 Curiously, Goodman's examples of hypotheses on which a discussion of projectibility is based are such that their antecedent predicates are uniformly sortals. At the end of his book, Goodman suggests (roughly) that an entrenched term comes to be regarded as a sortal, but if the suggestion of this paper is correct, a term could not be projected, and could not become entrenched, un- less it was a sortal to begin with.4 The conclusion of this paper is that we do not have to take sortals very seriously to see that many notions in con- temporary philosophy of science require serious rethinking.

Received March 21, 1967

NOTES 1See John R. Wallace, "Sortal Predicates and Quantification," Joumal of Philosophy,

62:8-13 (1965), and Peter Thomas Geach, Reference and Generality (Ithaca, N.Y.: Cornell University Press, 1962).

2 It's hard to imagine a reader not familiar with this paradox, due to Carl G. Hempel. But should he exist, he can consult Carl G. Hempel, "Studies in the Logic of Confirma- tion," Mind, n.s., 54:1-26, 97-121 (1945).

'See Nelson Goodman, Fact, Fiction, and Forecast (2nd ed., Indianapolis: Bobbs- Merrill, 1965), especially pp. 70-72.

' Ibid., pp. 121-22.

Partially Transparent Senses of Knowing

by JAAKKO HINTIKKA

UNIVERSITY OF HELSIK AND STANFORD

IN A recent note in this journal,' R. C. Sleigh, Jr, has criticized a line of argument I used in Knowledge and Belief2 against those (e.g., Quine) who



sortal predicates and confirmation

Documents