6 2 6 E I N S T E I N ’ S L E C T U R E A T K Y O T O U N I V E R S I T Y For us, however, this was extraordinarily useful. There are probably many dif- ferent books one can turn to if one wants to understand the contents of the the- ory of relativity. There is, however, no other source for the thoughts and efforts that the creator of the theory of relativity went through to arrive at his theory. Moreover, this is the only way to have the pleasure of hearing it directly from the professor. This is what the professor told the students:[5] After the account of the lecture in his book, Ishiwara added the following comments: Here we can see in detail how one of the few truly great physical theories in history was born thanks to profound considerations and observations and close friendships. Even with exceptional genius and effort, the brain of one person cannot always comprehend the infinitude of nature’s phenomena. It will be an unavoidable necessity but also a great pleasure to collaborate on this great task for humanity with unselfish kindness toward one another. I cannot but admire the mind of the professor, modestly emphasizing his good fortune and continu- ing his research in collaboration with others, especially when I see other people of far lesser stature boasting of their own minor discoveries or opposing this great theory for no good reason.[6] III Translations into English of Ishiwara’s account of Einstein’s lecture have been published by Yoshimasa A. Ono (Ono 1982, pp. 46–47) and Seiya Abiko (Abiko 2000, pp. 13–17), following an earlier partial translation by Tsuyoshi Ogawa (Ogawa 1979, pp. 79–80). Se- lected passages from an English translation by Akira Ukawa, revised by John Stachel, were published in Stachel 1982 and 1987. In 1986, a German translation was published by Hans- Joachim Haubold and Eiichi Yasui (Haubold and Yasui 1986, pp. 272–278). IV Ishiwara’s text gives an account of Einstein’s extemporaneous recollections about the creation and development of the theory of relativity many years after its publication. These reminiscences constitute a rich, if indirect, source for historians and philosophers of science and need to be read with all due caution called for by a document of this kind. In historical literature, the discussion of this document has focused mostly on a single controversial is- sue: Ishiwara writes that Einstein mentioned Michelson’s experiment and the role it played in shaping his insights into the relativity principle before the publication in 1905 of his pa- per “On the Electrodynamics of Moving Bodies” (Einstein 1905r [Vol. 2, Doc. 23]). The question as to when and how Einstein learned about Michelson’s experiment and what influence such knowledge about the experiment may have had on his path toward the theory of relativity has been debated for a long time.