30 INTRODUCTORY
in physics), we have a period of revolution. Thus the births of the relativities were
orderly transitions, the days of the old quantum theory were a revolutionary
period. I stress that this distinction is meant to apply to the historical process of
discovery, not to the content of one or another physical theory. (I would not argue
against calling the abandonment of the aether and the rejection of absolute simul-
taneity in 1905 and the rejection of Newton's absolute space in 1915 amazing,
astounding, audacious, bold, brave ... or revolutionary steps.)
No one appreciated the marked differences between the evolution of relativity
and quantum theory earlier and better than Einstein, the only man who had been
instrumental in creating both. Nor, of course, was anyone better qualified than he
to pronounce on the structure of scientific revolutions. After all, he had been to the
barricades. Let us see what he had to say about this subject.
Early in 1905 he wrote a letter to a friend in which he announced his forth-
coming papers on the quantum theory and on special relativity. He called the first
paper Very revolutionary.' About the second one he only remarked that 'its kine-
matic part will interest you' [E3].
In a report of a lecture on relativity that Einstein gave in London on June 13,
1921, we read, 'He [Einstein] deprecated the idea that the new principle was
revolutionary. It was, he told his audience, the direct outcome and, in a sense, the
natural completion of the work of Faraday, Maxwell, and Lorentz. Moreover
there was nothing specially, certainly nothing intentionally, philosophical about
it....'[Nl].
In the fall of 1919, in the course of a discussion with a student, Einstein handed
her a cable which had informed him that the bending of light by the sun was in
agreement with his general relativistic prediction. The student asked what he
would have said if there had been no confirmation. Einstein replied, 'Da konnt'
mir halt der liebe Gott leid tun. Die Theorie stimmt doch.' Then I would have to
pity the dear Lord. The theory is correct anyway [Rl]. (This statement is not at
variance with the fact that Einstein was actually quite excited when he first heard
the news of the bending of light (16b).)
These three stories characterize Einstein's lifelong attitude to the relativity the-
ories: they were orderly transitions in which, as he experienced it, he played the
role of the instrument of the Lord, Who, he deeply believed, was subtle but not
malicious.
Regarding Einstein's judgment of his own role in quantum physics, there is
first of all his description of his 1905 paper 'On a heuristic point of view concern-
ing the generation and transformation of light' as very revolutionary (19c). Next
we have his own summary: 'What I found in the quantum domain are only occa-
sional insights or fragments which were produced in the course of fruitless strug-
gles with the grand problem. I am ashamed* to receive at this time such a great
honor for this' [E4]. Those words he spoke on June 28,1929, the day he received
*I have translated Ich bin beschdmt as / am ashamed rather than as / am embarrassed because I
believe that the first alternative more accurately reflects Einstein's mood.