Einstein: His Life and Universe

. Einstein to Ernst Mach, June 25, 1913; Misner, Thorne, and Wheeler, 544.

28

. Einstein to Hendrik Lorentz, Aug. 14, 1913. But two days later, he writes Lorentz again to say that he has resigned himself to the belief that covariance is impossible: “Only now, after this ugly dark spot seems to have been eliminated, does the theory give me pleasure.” Einstein to Hendrik Lorentz, Aug. 16, 1913.

29

. The hole argument basically said that a generally covariant gravitational theory would be indeterministic. Generally covariant field equations could not determine the metric field uniquely. A full specification of the metric field outside of some small region that was devoid of matter, known as “the hole,” would not be able to fix the metric field within that region. See Stachel 1989b; Norton 2005b; Janssen 2004.

30

. Einstein to Ludwig Hopf, Nov. 2, 1913. See also Einstein to Paul Ehrenfest, Nov. 7, 1913: “It can be proved that

generally covariant

equations that determine

the field completely from the matter tensor cannot exist at all. Can there be anything more beautiful than this, that the necessary specialization follows from the conservation laws? Thus, the conservation laws determine the surfaces that, from among all the surfaces, are to be privileged as coordinate surfaces. We can designate these privileged surfaces as planes, since we are left with linear substitutions as the only ones that are justified.” Einstein’s clearest explanation of the hole argument is “On the Foundations of the Generalized Theory of Relativity and the Theory of Gravitation,” Jan. 1914, CPAE 4: 25.

31

. When Einstein appeared at the annual convocation of German-speaking scientists in Sept. 1913, the rival gravitation theorist Gustav Mie rose to launch a “lively” attack on him and subsequently published a violent polemic that displayed a vitriol far beyond anything explained by scientific disagreements. Einstein also engaged in a bitter debate with Max Abraham, whose own gravitational theory Einstein had attacked with great relish throughout 1912. Report on the Vienna conference, Sept. 23, 1913, CPAE 4: 17.

32

. Einstein to Heinrich Zangger, ca. Jan. 20, 1914.

33

. Einstein to Heinrich Zangger, Mar. 10, 1914. Jurgen Renn has pointed out that the 1913–1915 period of defending and refining the

Entwurf

, even though it did not save that theory, did help Einstein to better understand the difficulties that seemed to bedevil the tensors he had explored in the mathematical strategy. “Practically all of the technical problems Einstein had encountered in the Zurich notebook with candidates derived from the Riemann tensor were actually resolved in this period in the course of his examination of problems associated with the

Entwurf

theory.” Renn 2005b, 16.

34

. Einstein to Erwin Freundlich, Jan. 8, 1912, mid-Aug. 1913; Einstein to George Hale, Oct. 14, 1913; George Hale to Einstein, Nov. 8, 1913.

35

. Clark, 207.

36

. Einstein to Erwin Freundlich, Dec. 7, 1913.

37

. Einstein to Erwin Freundlich, Jan. 20, 1914.

38

. Folsing, 356–357.

39

. Einstein to Paul Ehrenfest, Aug. 19, 1914.

40

. Ibid.

41

. Einstein to Paolo Straneo, Jan. 7, 1915.

42

. For a good description from which this is drawn, see Levenson, especially 60–65.

43

. Elon, 277, 303–304.