THE FIELD EQUATIONS OF GRAVITATION 243currents of [our] time.. .. Hilbert regrets ... having neglected to foster interna-
tional relations more.. .. Planck does all he can to keep the chauvinist majority
of the Academy in check. I must say that in this respect the hostile nations are
well matched' [El3].
The strength of Einstein's own convictions was not lessened by the amused
detachment with which throughout his life he regarded human folly. 'I begin to
feel comfortable amid the present insane tumult (wahnsinnige Gegenwartsrum-
mel), in conscious detachment from all things which preoccupy the crazy com-
munity (die verriickte Allgemeinheit). Why should one not be able to live con-
tentedly as a member of the service personnel in the lunatic asylum? After all, one
respects the lunatics as the ones for whom the building in which one lives exists.
Up to a point, one can make one's own choice of institution—though the distinc-
tion between them is smaller than one thinks in one's younger years' [El4].
Einstein's initial hopes that the voices of reason might prevail yielded to increas-
ing pessimism as the war dragged on. In 1917 he wrote to Lorentz, 'I cannot help
being constantly terribly depressed over the immeasurably sad things which bur-
den our lives. It no longer even helps, as it used to, to escape into one's work in
physics' [El5]. These feelings of dejection may have been enhanced, I think, by
Einstein's own illness at that time.
After this digression on Einstein and the war, I return to the developments in
general relativity. We are in the fall of 1914, at which time Einstein wrote a long
paper for the proceedings of the Prussian Academy [El6]. Its main purpose was
to give a more systematic and detailed discussion of the methods used and the
results obtained in the first paper with Grossmann [El7]. Nearly half the paper
deals with an expose of tensor analysis and differential geometry. Einstein clearly
felt the need to explain these techniques in his own way; they were as new to him
as to most other physicists. The paper also contains several new touches concern-
ing physics. First of all, Einstein takes a stand against Newton's argument for the
absolute character of rotation (as demonstrated, for example, by Newton's often
reproduced discussion of the rotating bucket filled with water [Wl]). Instead, Ein-
stein emphasizes, 'we have no means of distinguishing a "centrifugal field" from
a gravitational field, [and therefore] we may consider the centrifugal field to be a
gravitational field.' The paper contains another advance. For the first time, Ein-
stein derives the geodesic equation of motion of a point particle (cf. Eq. 12.28)
[E18] and shows that it has the correct Newtonian limit (cf. Eq. 12.30) [E19]. He
also shows that his earlier results about the red shift and the bending of light (still
the old value, off by a factor of 2) are contained in the tensor theory [E20]. As a
final positive result, an important comment about the character of space-time
should be mentioned, which (to my knowledge) he makes here for the first time:
'According to our theory, there do not exist independent (selbstandige) qualities
of space' [E21].
Regarding the covariance properties of the gravitational field equations, how-
ever, there is no progress. If anything, the situation is getting slightly worse.
We saw in Section 12d that early in 1913 Einstein and Grossmann had been