Knowledge and Necessity pp 155-168 | Cite as

# Physical Determinism

## Abstract

The object of this paper is to examine what evidence we can have for or against the truth of determinism, a doctrine often set forward by the proposition ‘every event has a cause’. I understand in this context by the cause of an event a set of prior conditions jointly sufficient for the occurrence of the event. Since the determinist is concerned with all physical states and not merely with changes of states, which are most naturally termed events, we may phrase this claim more precisely as follows : There is for every physical state at some earlier instant a set of conditions jointly sufficient for its occurrence.

## Keywords

Quantum Theory Scientific Theory Physical Object Fundamental Theory Objective World## Preview

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## Notes

- 1.B. Russell,
*The Analysis of Mind*(London, 1921) p. 78.Google Scholar - 1.Laplace, of course, made this larger claim in the famous remark: ‘Une intelligence qui, pour un instant donné, connaîtrait toutes les forces dont la nature est animée, et la situation respective des êtres qui la composent, si d’ailleurs elle était assez vaste pour soumettre ces données à l’analyse, embrasserait dans la même formule les mouvements des plus grands corps de l’univers et ceux du plus léger atome : rien ne serait incertain pour elle, et l’avenir comme le passé serait présent à ses yeux. L’esprit humain offre dans la perfection qu’il a su donner à l’astronomie une faible esquisse de cette intelligence.’ P. S. de Laplace,
*Theorie Analytique des Probabilités, Introduction. Œuvres Complètes*(Paris, 1847) VII, p. vi.Google Scholar - 2.See, for example, A. Pap,
*An Introduction to the Philosophy of Science*(New York, 1962) p. 311, where he is in doubt whether to treat the sentence as making a claim or giving a piece of advice.Google Scholar - 1.Warnock has argued in favour of the view that the sentence makes a statement, but claims that the statement is vacuous, because nothing could count against it. There could never, he writes, ‘occur any event which it would be necessary or even natural to describe as an uncaused event’. (G. J. Warnock, ‘Every event has a cause’, in
*Logic and Language*, Second Series, ed. A. G. N. Flew (Oxford, 1953) p. 106.) Men have been mistaken, Warnock claims, in considering the scientific evidence which they have adduced to be relevant to the cited claim. I hope to show this view to be mistaken by analysing in detail what would count for or against the claim.Google Scholar - 2.I. Kant,
*Critique of Pure Reason, Second Analogy*. For detailed criticism of Kant’s arguments, see J. F. Bennett,*Kant’s Analytic*(Cambridge, 1966) ch. 15,CrossRefGoogle Scholar - and P. F. Strawson,
*The Bounds of Sense*(London, 1966) Part 11, Section 3.Google Scholar - 1.K. R. Popper, ‘Indeterminism in Quantum Physics and Classical Physics’, in
*British Journal of the Philosophy of Science*, 1 (1950), 117–33 and 173–95.Google Scholar - 1.A well-known theorem of von Neumann has sometimes been interpreted as a proof that no more fundamental theory T
_{3}yielding perfect predictions of all physical states, yet making all the predictions of the statistical theory T_{1}, can even be constructed, let alone confirmed, for quantum theory as T_{1}. The most that von Neumann proved, however, is that the basic laws of quantum theory cannot be supplemented by laws containing ‘hidden parameters’, that is, laws about further properties of physical systems, in such a way as to yield perfect predictions of all physical states, where present quantum theory yields only statistical predictions. (See J. von Neumann,*Mathematical Foundations of Quantum Mechanics*, English edition (Princeton, N.J., 1955) Ch. 4.) But all that this means is that the axiom set of T_{3}cannot consist of T_{1}and certain other laws as well; it must drop at any rate some of the laws of T_{1}and bring in laws about properties of different kinds. T_{3}could nevertheless yield all the predictions of T_{1}and further predictions as well. (This was shown by Bohm: see David Bohm, ‘A suggested interpretation of the Quantum Theory in terms of Hidden Variables’, in*Physical Review*, lxxxv (1952) 166–93, esp. 187 f.) Some T_{3}must always be constructible, at any rate in the trivial way described on p. 165, from the statistical laws about physical states and their properties deducible from T_{1}and put in the form ‘n% A’s are B’. The fundamental laws of quantum theory are of course normally expressed in a far more complicated notation than this.Google Scholar