THE PRAGUE PAPERS 2O1lie. 1912. Einstein in No Man's Land
Another eight months passed before Einstein made his next move in the theory of
gravitation. A scientific meeting at Karlsruhe, summer lectures at Zurich, and a
few minor papers kept him busy in the meantime. But principally he was once
again otherwise engaged by the quantum theory. This time, however, it was not
so much because that seemed the more compelling subject to him. Rather he had
taken on the obligation to prepare a major report on quantum physics for the first
Solvay Congress (October 30 to November 3, 1911). 'I am harassed by my drivel
for the Brussels Congress,' he wrote to Besso [E13]. He did not look forward to
the 'witches' sabbath in Brussels [El4].
He found the congress interesting and especially admired the way in which
Lorentz presided over the meetings. 'Lorentz is a marvel of intelligence and fine
tact. A living work of art! He was in my opinion still the most intelligent one
among the theoreticians present' [El2]. He was less impressed with the outcome
of the deliberations: '... but no one knows anything. The whole affair would
have been a delight to Jesuit fathers' [E12]. 'The congress gave the impression of
a lamentation at the ruins of Jerusalem' [E15]. Obviously, these were references
to the infringements of quantum physics on classically conditioned minds. Einstein
gave the final address at the congress. His assigned subject was the quantum the-
ory of specific heats. In actual fact, he critically discussed all the problems of quan-
tum theory as they were known to exist at a time when the threats and promises
of the hydrogen atom were yet to be revealed. I shall return to this subject in
Chapter 20. As to Einstein's contribution, drivel it was not.
Then, in rapid succession, Einstein readied two papers on gravitation, one in
February 1912 [E16] and one in March 1912 [E17] (referred to in this section as
I and II, respectively). These are solid pieces of theoretical analysis. It takes some
time to grasp their logic. Yet these 1912 papers give the impression less of finished
products than of well-developed sketches from a notebook. Their style is irresolute.
The reasons for this are clear. In 1907 and 1911 Einstein had stretched the kine-
matic approach to gravitation to its limits. This time he embarked on one of the
hardest problems of the century: to find the new gravitational dynamics. His first
steps are taken gingerly.
These are also the last papers in which time is warped but space is flat. Already,
for the first time in Einstein's published work, the statement appears in paper I
that this treatment of space
is not obviously permissible but contains physical assumptions which might
ultimately prove to be incorrect; for example, [the laws of Euclidean geometry]
most probably do not hold in a uniformly rotating system in which, because of
the Lorentz contraction, the ratio of the circumference to the diameter should
be different from ir if we apply our definition of lengths.