News and Views

Editor’s Note

In the early 1930s, physicists were exploring the profound philosophical repercussions of quantum theory. Heisenberg’s principle of indeterminacy apparently established clear limitations to determinism in physics. Did an absence of deterministic laws at the microscale undermine cause and effect? In a supplement to this issue, Arthur Eddington considered the “decline of determinism”, insisting that indeterministic “secondary” law can still be useful for predicting the future. The author of this essay takes issue with that point, saying that Eddington proclaims the demise of determinism while at the same time supposing its implications for orderly causal links, and even the possibility of prediction, remain. But the essay applauds Eddington’s statement that quantum indeterminacy does not imply a universe characterised by unrestrained caprice.　　中文

Determinism Defined

SIR Arthur Eddington’s characteristically fascinating address on “The Decline of Determinism”, which we publish as our Supplement this week, will be welcomed as a clear, unequivocal statement, by a leading authority, on a question which, even among the many revolutionary aspects of the new physics, holds a pre-eminent place for importance and interest. Such a statement is the more necessary because of the almost universal tendency for discussions of determinism to be concerned at bottom with words rather than ideas, and Sir Arthur has quite properly begun by stating definitely what he means by the determinism which he holds has declined. His thorough analysis leaves little room for disagreement, but many will wonder whether he has not achieved a Pyrrhic victory by conceding to the determinist the substance of his doctrine and destroying only the shadow. “The rejection of determinism is in no sense an abdication of scientific method”, and “indeterministic or secondary law … can be used for predicting the future as satisfactorily as primary law”. In other words, Sir Arthur does not allow that the first Morning of Creation wrote what the last Dawn of Reckoning shall read, but he allows that it might have read what the last Dawn shall write. Even the most perfervid determinist will scarcely ask more. Furthermore, he acknowledges that he does not know whether Dirac, whose book “goes as deeply as anyone has yet penetrated into the fundamental structure of the physical universe”, is a determinist or not. It would seem, therefore, that the determinism in question cannot be of much importance even in physics.　　中文

Physical Inference and Prediction

Apparently, however, in spite of the unqualified statement concerning prediction quoted above, Sir Arthur denies that we can predict the behaviour of electrons more certainly than that of horses, and the importance, to all but the physicist, of the “decline of determinism” therefore depends on the recognition of electrons as bodies co-equal with ordinary physical objects. To establish this he claims that since physical objects, as well as electrons and such particles, are all “inferences”, they differ only in degree and not in kind. We must not, however, be deceived by words. Objects which we see and handle may be, as he says, as inferential as an undiscovered planet inferred from irregularities in the motion of Uranus, but the inferences are of different kinds; otherwise, why, when a planet was seen in a different position from that inferred from the irregularities, was it without question preferred to the “undiscovered” inferential planet? There was not even an instinctive estimate of the “degree” of validity to be attributed to the two “inferences”. Unless Sir Arthur assigns to “direct observation” a status essentially different from that of rational deduction, it is difficult to see how his position can be “in no sense an abdication of scientific method”. All this, however, does not affect determinism in relation to physical objects, and it is to be hoped that Sir Arthur’s plain statement will do much to remove the widespread delusion that modern physics has revealed a universe of unrestrained caprice.　　中文

(129, 228-229; 1932)