D O C . 1 0 R E V I E W O F W E Y L ’ S S P A C E – T I M E – M A T T E R 6 3

his easy mastery of the mathematical form, but also his deep insight into what is

essential in physics.

Recently, Weyl has earned considerable merits by the integration of the field

equations of gravitation. The expositions of the last paragraphs exemplify how a

born mathematician can be effective here through simplifying and clarifying. The

book will be invaluably helpful to everybody who wants to work in this field, not

to mention the pure joy derived from its study.

For the sake of completeness, I want to mention that I do not completely agree

with the author’s interpretation of the energy theorem and also not with his view of

the relation between statements of theoretical physics and reality. Furthermore, in

the interest of the completeness of the presentation from a physicist’s point of view,

I would like to see that the physical meaning of distance (as a direct result of mea-

surements with measuring rods and clocks) should be put more into the foreground

in a second edition.—The book presumes the ability to think rigorously but re-

quires relatively little preliminary knowledge. The effort to study it is brilliantly re-

warded, and there is perhaps hardly anyone who could not learn from this book.

A. Einstein, Berlin

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