25
Einstein's Response
to the New Dynamics
Everyone familiar with modern physics knows that Einstein's attitude regarding
quantum mechanics was one of skepticism. No biography of him fails to mention
his saying that God does not throw dice. He was indeed given to such utterances
(as I know from experience), and stronger ones, such as 'It seems hard to look in
God's cards. But I cannot for a moment believe that He plays dice and makes use
of "telepathic" means (as the current quantum theory alleges He does)' [El].
However, remarks such as these should not create the impression that Einstein
had abandoned active interest in quantum problems in favor of his quest for a
unified field theory. Far from it. In fact, even in the search for a unified theory,
the quantum riddles were very much on his mind, as I shall discuss in Chapter- In the present chapter, I shall describe how Einstein's position concerning
quantum mechanics evolved in the course of time. To some extent this is reflected
in his later scientific papers. It becomes evident more fully in several of his more
autobiographical writings and in his correspondence. My own understanding of
his views has been helped much by discussions with him.
To begin with, I turn to the period 1925-31, during which he was much con-
cerned with the question, Is quantum mechanics consistent?
25a. 1925-31: The Debate Begins
Schroedinger was not the only one who had profited from the study of Einstein's
three papers on the new gas theory. Half a year before Schroedinger's first paper
on wave mechanics, Walter Elsasser, likewise acknowledging the stimulus of Ein-
stein's articles, suggested that slow electrons would be ideally suited for testing
'[ Einstein's] assumption that to every translational motion of a particle one must
associate a wavefield which determines the kinematics of the particle' [E2]. He
also pointed out that the existing experimental results of Ramsauer, Davisson and
Kunsman, and others already seemed to give evidence of diffraction and interfer-
ence of matter waves. Heisenberg wrote to Pauli that, after having studied Ein-
stein's papers, he was enthusiastic about Elsasser's ideas [HI].
Also Einstein himself continued thinking about the meaning of wavefields, old
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