4 6 2 D O C . 3 1 8 C R I S I S O F T H E O R E T I C A L P H Y S I C S Published in Kaizo 4, no. 12 (December 1922): 1–8. Dated August 1922. Two fragments of its manuscript [36 426] are also available. The original title of the manuscript, “Über die Krise der Licht-Theorie,” was changed to the present one by interlineation of “gegenwärtige” and deletion of “Licht-Theorie.” Einstein makes a similar remark about the axiomatic character of physical theory in Einstein 1922i (Doc. 220). In Einstein 1920j (Vol. 7, Doc. 38), Einstein similarly identifies the ether with properties of space. See, e.g., Hertz 1889 and 1892. For earlier expressions by Einstein on the methods and results of field theory as constituting a “revolution” (‘‘Umwälzung’’) in the foundations of physics, see, e.g., Einstein 1914o (Vol. 6, Doc. 9), p. 122. Einstein refers here to the so-called electromagnetic program, the attempt to reduce mechanics to electromagnetic theory. For a clear statement of the research program, see Wien 1900, p. 502 for historical discussions, see Kragh 1999, chap. 9 McCormmach 1970 and Jungnickel and McCorm- mach 1986, pp. 227–245. See Thomson 1881, Abraham 1902. For an explicit reminiscence by Einstein on the genesis of the special and general theories of rel- ativity, see Doc. 399. See Einstein 1921c (Vol. 7, Doc. 52) for a discussion of Einstein’s philosophy of geometry in the wake of relativity theory. Almost exactly the same statement can be found in Einstein’s King’s College Lecture of 1921, namely that general relativity is “apparently” a “completion” (“Abschluss”) of the field-theoretic pro- gram which had been introduced by Faraday and Maxwell (Vol. 7, Doc. 58, p. 431.) See Planck 1900. See Einstein 1907a (Vol. 2, Doc. 38). See Einstein 1905i (Vol. 2, Doc. 14). Einstein 1922l (Doc. 231), p. 828, gives details on the experiment he refers to in the current doc- ument. In the last paragraph of the present document, Einstein comes back to the question of whether field theory can serve as a foundation for physics by discussing the suitability of differential equations (see note 19). See in particular Rutherford 1906 and Bohr 1913. For a comprehensive treatment of the histor- ical development of quantum theory, see Mehra and Rechenberg 1982. The works Einstein has in mind probably include Bohr 1913, Sommerfeld 1916a and 1916b, Epstein 1916, and Schwarzschild 1916. See Epstein 1916. Einstein voiced such doubts in Einstein to Walter Dällenbach, 15 February 1917 (Vol. 8, Doc. 299). Stachel 1993 speaks of “the two Einsteins” when providing a historical discussion of the two incompatible programs of seeking a foundation for physics either by field-theoretical methods (using a continuous manifold and partial differential equations) or seeking a more algebraic founda- tion to account for the discrete phenomena of quantum theory.