26
Einstein's Vision
26a. Einstein, Newton, and Success
Einstein's lasting conviction that quantum mechanics was not a theory of principle
did not impede him from recognizing that this theory was highly successful. As
early as 1927, he publicly expressed his judgment that wave mechanics is 'in
amazing agreement with the facts of experience' [El]. In 1936 he wrote, 'It seems
clear... that the Born statistical interpretation of the quantum theory is the only
possible one' [E2], and in 1949 declared, 'The statistical quantum theory [is] the
most successful theory of our period' [E3]. Then why was he never convinced by
it?
I believe Einstein indirectly answered this question in his 1933 Spencer lec-
ture—perhaps the clearest and most revealing expression of his way of thinking
in later life. The key is to be found in his remarks on Newton and classical
mechanics. In this lecture [E4], Einstein noted that 'Newton felt by no means
comfortable about the concept of absolute space, ... of absolute rest ... [and]
about the introduction of action at a distance.' Then he went on to refer to the
success of Newton's theory in these words: 'The enormous practical success of his
theory may well have prevented him and the physicists of the eighteenth and nine-
teenth centuries from recognizing the fictitious character of the principles of his
system.' It is important to note that by fictitious Einstein meant free inventions of
the human mind. Whereupon he compared Newton's mechanics with his own
work on general relativity: 'The fictitious character of the principles is made quite
obvious by the fact that it is possible to exhibit two essentially different bases
[Newtonian mechanics and general relativistic mechanics] each of which in its
consequences leads to a large measure of agreement with experience.' (Remember
that these words were spoken long before it was realized how markedly the pre-
dictions of Newtonian mechanics differ from those of general relativity when
strong grativational fields come into play.)
In the Spencer lecture, Einstein mentioned the success not only of classical
mechanics but also of the statistical interpretation of quantum theory. 'This con-
ception is logically unexceptionable and has led to important successes.' But, he
added, 'I still believe in the possibility of giving a model of reality which shall
represent events themselves and not merely the probability of their occurence.'
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