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Temporally-Asymmetric Principles, Parity between Explanation and Prediction, and Mechanism Versus Teleology

Published online by Cambridge University Press:  14 March 2022

Adolf Grünbaum
Adolf Grünbaum*
Affiliation:
University of Pittsburgh
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Abstract

Three major ways in which temporal asymmetries enter into scientific induction are discussed as follows:

1. An account is given of the physical basis for the temporal asymmetry of recordability, which obtains in the following sense: except for humanly recorded predictions and one other class of advance indicators to be discussed, interacting systems can contain reliable indicators of only their past and not of their future interactions. To deal with the exceptional cases of non-spontaneous “pre-records,” a clarification is offered of the essential differences in the conditions requisite to the production of an indicator having retrodictive significance (“post-record”), on the one hand, and of one having predictive significance (“prerecord” or recorded prediction), on the other. Purported counter-examples to the asymmetry of spontaneous recordability are refuted.

2. It is shown how in cases of asymmetric recordability, the associated retrodiction-prediction asymmetry makes for an asymmetry of assertibility as between an explanandum (or an explanans) referring to a future event and one referring to a past one. But it is argued that this epistemological asymmetry in the assertibility per se must be clearly distinguished from a logical asymmetry between the past and the future in regard to the inferability (deductive or inductive) of the explanandum from the explanans. And it is then contended that the failure to distinguish between an epistemological and a logical asymmetry vitiates the critiques that recent writers have offered of the Popper-Hempel thesis, which affirms symmetry of inferability as between predictive and post-explanatory arguments. In reply to Scriven, it is maintained that predictions based on mere indicators (rather than causes) do not establish an asymmetry in scientific understanding as between predictive arguments and post-explanatory ones.

3. As a further philosophical ramification of the retrodiction-prediction asymmetry, a set of sufficient conditions are stated for the correctness of philosophical mechanism as opposed to teleology.

Type
Research Article
Information
Philosophy of Science , Volume 29 , Issue 2 , April 1962 , pp. 146 - 170
Copyright
Copyright © Philosophy of Science Association 1962

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Footnotes

∗∗

An earlier version of this paper was presented at the Conference on Induction, held at the Wesleyan Center for Advanced Studies in June, 1961. It is published here by agreement with the Wesleyan University Press.

I am indebted to Professor Allen I. Janis for helpful discussions of aspects of statistical mechanics relevant to §2. The treatment of the barometer as an advance indicator in §2 benefited from a criticism which Mr. Nicholas LaPara made of an earlier formulation.

After completing this paper, I became aware that some of the objections to the Popper-Hempel thesis which are criticized in my §3 were also discussed independently by Professor May Brodbeck in her essay “Explanation, Prediction and ‘Imperfect Knowledge’ “, which is to appear in H. Feigl & G. Maxwell (editors), Minnesota Studies in the Philosophy of Science, vol. III. Unfortunately, it was too late to make specific mention of Professor Brodbeck's contributions within the text.

References

1 For a discussion of the conditions under which the inverse asymmetry obtains, see A. Grünbaum, “Das Zeitproblem,” Archiv für Philosophie, vol. 7, 1957, pp. 184–185. Cf. also, M. S. Watanabe, “Symmetry of Physical Laws. Part III. Prediction and Retrodiction,” Reviews of Modern Physics, vol. 27, 1955, pp. 179–186.

2 Cf. H. Reichenbach, The Direction of Time, Berkeley, 1956, p. 118.

3 Cf. R. C. Tolman, The Principles of Statistical Mechanics, Oxford, 1938, p. 149.

4 Cf. R. Fürth, “Prinzipien der Statistik,” Handbuch der Physik, Vol. 4, 1929, pp. 270 and 192–193.

5 Ibid., p. 270.

6 Although the decisive asymmetry just noted was admitted by H. Mehlberg [“Physical Laws and Time's Arrow,” in: Current Issues in the Philosophy of Science (ed. Feigl & Maxwell), New York, 1961, p. 129], he dismisses it as expressing “merely the factual difference between the two relevant values of probability.” But an asymmetry is no less an asymmetry for depending on de facto, nomologically-contingent, boundary conditions rather than being assured by a law alone. Since our verification of laws generally has the same partial and indirect character as that of our confirmation of the existence of certain complicated de facto boundary conditions, the assertion of an asymmetry depending on de facto conditions is generally no less reliable than one wholly grounded on a law. Hence when Mehlberg [op. cit., p. 117, n. 30] urges against Schrödinger's claim of asymmetry that for every pair of branch systems which change their entropy in one direction, “there is nothing to prevent” another pair of closed subsystems from changing their entropy in the opposite direction, the reply is: Mehlberg's criticism can be upheld only by gratuitously neglecting the statistical asymmetry admitted but then dismissed by him as “merely” factual. For a more detailed criticism of Mehlberg's denial of temporal anisotropy, see A. Grünbaum, Philosophical Problems of Space and Time, Alfred A. Knopf, New York (forthcoming).

7 Readers familiar with Reichenbach's “hypothesis of the branch structure” as set forth in his The Direction of Time (p. 136) will note that though heavily indebted to Reichenbach, my treatment of the assumptions regarding branch systems departs from Reichenbach's in several essential respects. A statement and justification of these departures is given in A. Grünbaum, “Carnap's Views on the Foundations of Geometry,” footnote 97 in: P. A. Schilpp (ed.), The Philosophy of Rudolf Carnap, Open Court Publishing Co., LaSalle, Illinois, 1962.

8 This is not to say that entropie changes are the sole source of the anisotropy of time. But processes which are de facto irreversible though not involving any entropy increase [Cf. K. R. Popper, “The Arrow Time,” Nature 177, 538 and 178, 382 (1956); E. L. Hill and A. Grünbaum, “Irreversible Processes in Physical Theory,” Nature 179, 1296 (1957), and A. Grünbaum, “Popper on Irreversibility,” in M. Bunge (ed.), The Critical Approach, Essays in Honor of Karl Popper, to be published by the Free Press, Glencoe, Ill.] are not of importance for the asymmetry between retrodiction and prediction, which is our guiding concern in this section.

9 The two exceptions, which we shall discuss in some detail below, are constituted by the following two classes of advance indicators: (i) veridical predictions made and stored (recorded) by human (or other sentient, theory-using) beings, and physically-registered, bona fide advance indicators produced by computers, and (ii) advance indicators (e.g. sudden barometric drops) which are produced by the very cause (pressure change) that also produces the future interaction (storm) indicated by them.

10 I refer here to the original paper of C. G. Hempel and P. Oppenheim: “Studies in the Logic of Explanation,” Philosophy of Science, 15, 135 (1948). For Hempel's most recent statement of his account of scientific explanation, see his forthcoming “Deductive Nomological vs. Statistical Explanation,” Minnesota Studies in the Philosophy of Science (ed. Feigl and Maxwell), vol. III, Minneapolis, 1962.

11 C. G. Hempel and P. Oppenheim, op. cit., § 3.

12 “The logical similarity of explanation and prediction, and the fact that one is directed towards past occurrences, the other towards future ones, is well expressed in the terms “postdictability” and “predictability” used by Reichenbach in [Quantum Mechanics], p. 13.”

13 N. Rescher, “On Prediction and Explanation,” British Journal for the Philosophy of Science, 8, 281, (1958).

14 S. F. Barker, “The Role of Simplicity in Explanation,” in: Current Issues in the Philosophy of Science (ed. Feigl and Maxwell), New York, 1961, pp. 265–286 and the Comments on this paper by Salmon, Feyerabend and Rudner with Barker's Rejoinders.

15 N. R. Hanson, “On the Symmetry Between Explanation and Prediction,” The Philosophical Review 68, 349 (1959).

16 M. Scriven, “Explanation and Prediction in Evolutionary Theory,” Science 130, 477 (1959) and “Explanations, Predictions and Laws,” in: H. Feigl & G. Maxwell (eds.) Minnesota Studies in the Philosophy of Science, vol. III, Minneapolis, 1962.

17 M. Scriven, “Explanations, Predictions and Laws,” op. cit., Section 3.4.

18 Hempel, “Deductive-Nomological vs. Statistical Explanation,” op. cit., Section 6.

19 Scriven, “Explanation and Prediction in Evolutionary Theory,” op. cit., p. 479.

20 I. Sheffler, “Explanation, Prediction and Abstraction,” British J. Phil. of Science, 7, 293 (1957).

21 Rescher, op. cit., p. 282.

22 Ibid., p. 284.

23 Barker, op. cit., p. 271.

24 Hanson, “On the Symmetry Between Explanation and Prediction,” op. cit., pp. 353–354.

25 Ibid., p. 357.

26 M. Scriven, “Explanation and Prediction in Evolutionary Theory,” op. cit., p. 477.

27 Ibid., p. 480.

28 The environmental changes which Scriven goes on to cite are all of the nature of interactions of a potentially open system. And it is this common property of theirs which makes for their role in precluding the predictability of survival.

29 Ibid., p. 478.

In a recent paper “Cause and Effect in Biology,” [Science 134 (1961), p. 1504], the zoologist E. Mayr overlooks the fallacy in Scriven's statement which we are about to point out and credits Scriven with having “emphasized quite correctly that one of the most important contributions to philosophy made by the evolutionary theory is that it has demonstrated the independence of explanation from prediction.” And Mayr rests this conclusion among other things on the contention that “The theory of natural selection can describe and explain phenomena with considerable precision, but it cannot make reliable predictions.”

30 Ibid., p. 480.

31 Cf. C. G. Hempel, “Deductive-Nomological vs. Statistical Explanation,” op. cit., Section 4.

32 M. Scriven, “Explanation and Prediction in Evolutionary Theory,” op. cit., p. 480.

33 Believing (incorrectly) to have cleansed Euclid of all blemish, G. Saccheri (1667–1733) published a book (Milan, 1733) under the title Euclides ab omni naevo vindicatus.

34 Reichenbach, The Direction of Time, op. cit., p. 154.