einstein

71. Einstein to Elsa Einstein, Oct. 16, 1913.
72. Einstein to Elsa Einstein, before Dec. 2, 1913.
73. Einstein to Elsa Einstein, after Dec. 21 and Aug. 11, 1913.
74. Einstein to Elsa Einstein, after Dec. 21, 1913.
75. Einstein to Elsa Einstein, after Feb. 11, 1914; Lisbeth Hurwitz diary, cited in Overbye, 265.
76. Marianoff, 1; Einstein to Mileva Mari , Apr. 2, 1914.
77. Einstein to Paul Ehrenfest, ca. Apr. 10, 1914; Paul Ehrenfest to Einstein, ca. Apr. 10, 1914; Highfield and Carter, 167.
78. Whitrow, 20.
79. Einstein to Heinrich Zangger, June 27, 1914, CPAE 8: 16a, made available in 2006 and printed in a supplement to vol. 10.
80. Einstein, Memorandum to Mileva Mari , ca. July 18, 1914, CPAE 8: 22. See also appendix, CPAE 8b (German edition), p. 1032, for a
memo from Anna Besso-Winteler to Heinrich Zangger, Mar. 1918, about the Einstein breakup.
81. Einstein to Mileva Mari , ca. July 18 and July 18, 1914.
82. CPAE 8a: 26 (German edition), footnote 3; memo from Anna BessoWinteler to Heinrich Zangger, Mar. 1918, CPAE 8b (German edition),
p. 1032; Overbye, 268.
83. Einstein to Elsa Einstein, July 26, 1914.
84. Einstein to Elsa Einstein, after July 26, 1914.
85. Einstein to Elsa Einstein, July 30, 1914 (two letters); Michele Besso to Einstein, Jan. 17, 1928 (recalling the breakup); Pais 1982, 242;
Fölsing, 338.
86. Einstein to Elsa Einstein, after Aug. 3, 1914.
87. Einstein to Mileva Mari , Sept. 15, 1914, contains the poisoning allegation. Many other letters in 1914 detail their struggle over money,
furniture, and treatment of the children.
CHAPTER NINE: GENERAL RELATIVITY
1. Renn and Sauer 2006, 117.
2. The description of the equivalence principle follows the formulation that Einstein used in his yearbook article of 1907 and his comprehensive
general relativity paper of 1916. Others have subsequently modified it slightly. See also Einstein, “Fundamental Ideas and Methods of
Relativity Theory,” 1920, unpublished draft of a paper for Nature magazine, CPAE 7: 31.
Some of this chapter draws from a dissertation by one of the editors of the Einstein Papers Project: Jeroen van Dongen, “Einstein’s
Unification: General Relativity and the Quest for Mathematical Naturalness,” 2002. He provided a copy to me along with guidance and editing
for this chapter. This chapter also follows the research findings of other scholars studying Einstein’s general relativity work. I am grateful to van
Dongen and others who met with me and helped me on this chapter, including Tilman Sauer, Jürgen Renn, John D. Norton, and Michel
Janssen. This chapter draws on their work and also that of John Stachel, all listed in the bibliography.
3. Einstein, “The Speed of Light and the Statics of the Gravitational Field,”Annalen der Physik (Feb. 1912), CPAE 4: 3; Einstein 1922c;
Janssen 2004, 9. In his 1907 and 1911 papers, Einstein refers to it as the “equivalence hypothesis,” but in this 1912 paper, he raises it to
the status of an Aequivalenzprinzip.
4. Einstein, “On the Influence of Gravitation on the Propagation of Light,”Annalen der Physik (June 21): 1911, CPAE 3: 23.
5. Einstein to Erwin Freundlich, Sept. 1, 1911.
6. Stachel 1989b.
7. Record and grade transcript, CPAE 1: 25; Adolf Hurwitz to Hermann Bleuler, July 27, 1900, CPAE 1: 67; Einstein to Mileva Mari , Dec. 28,
1901.
8. Fölsing, 314; Pais 1982, 212.
9. Hartle, 13.
10. Einstein to Arnold Sommerfeld, Oct. 29, 1912.
11. Einstein, foreword to the Czech edition of his popular book Relativity, 1923; see utf.mff.cuni.cz/Relativity/Einstein.htm. In it Einstein writes,
“The decisive idea of the analogy between the mathematical formulation of the theory and the Gaussian theory of surfaces came to me
only in 1912 after my return to Zurich, without being aware at that time of the work of Riemann, Ricci, and Levi-Civita. This was first
brought to my attention by my friend Grossmann.” Einstein 1922c: “I realized that the foundations of geometry have physical significance.
My dear friend the mathematician Grossmann was there when I returned from Prague to Zurich. From him I learned for the first time about
Ricci and later about Riemann.”
12. Sartori, 275.
13. Amir Aczel, “Riemann’s Metric,” in Aczel 1999, 91–101; Hoffmann 1983, 144–151.
14. I am grateful to Tilman Sauer and Craig Copi for help with this section.
15. Janssen 2002; Greene 2004, 72.
16. Calaprice, 9; Flückiger, 121.
17. The Zurich Notebook is in CPAE 4: 10. An online facsimile is available at echo.mpiwg-berlin.mpg.de/content/relativityrevolution/jnul. See
also Janssen and Renn.
18. Norton 2000, 147. See also Renn and Sauer 2006, 151. I am grateful to Tilman Sauer for his editing of this section.
19. Einstein, Zurich Notebook, CPAE 4: 10 (German edition), p. 39 has the first notations of what became known as the Einstein tensor.
20. An explanation of this dilemma is in Renn and Sauer 1997, 42–43. The mystery of why Einstein in early 1913 could not find the correct
gravitational tensor—and the issue of his understanding of coordinate condition options—is addressed nicely in Renn 2005b, 11–14. He
builds on, and suggests some revisions to, the conclusions of Norton 1984.
21. Norton, Janssen, and Sauer have all suggested that Einstein’s bad experience in 1913 of abandoning a mathematical strategy for a
physical one, and his subsequent belated success with a mathematical strategy, is reflected in the views he expressed in his 1933
Spencer lecture at Oxford and also his approach in the later decades of his life to finding a unified field theory.
22. Einstein, “Outline [Entwurf ] of a Generalized Theory of Relativity and of a Theory of Gravitation” (with Marcel Grossmann), before May 28,
1913, CPAE 4: 13; Janssen 2004; Janssen and Renn.
23. Einstein to Elsa Einstein, Mar. 23, 1913.
24. Einstein-Besso manuscript, CPAE 4: 14; Janssen, 2002.