van Dongen, Jeroen Einstein’s methodology, semivectors and the unification of electrons and protons. (English) Zbl 1065.01011 Arch. Hist. Exact Sci. 58, No. 3, 219-254 (2004). This article on the historical development of Einstein’s physics and related epistemology deals with the role that Einstein’s methodological convictions played in his work on classical field theory. Starting with Einstein’s Oxford lecture of June 1933 [On the Method of Theoretical Physics. Oxford: Clarendon Press (1933; JFM 59.0066.04)], the author argues that according to Einstein fundamental principles of physics cannot be derived from experience, and that Einstein’s strong emphasis on the creative merit of mathematics echoes his experiences with the formulation of the general theory of relativity. The central topic of the paper is Einstein’s work on the Dirac equation and the so-called semivector, which was introduced by Einstein as a generalization of the spinors in Dirac’s equation. As the four papers that Einstein published on semivectors between 1932 and 1934 were co-authored by Walther Mayer, the author gives some biographical information about this rather unknown collaborator and assistant of Einstein. Mayer, a Privatdozent from Vienna, had been brought to Einstein’s attention by the Vienna mathematical physicist Richard von Mises, and as Einstein highly appreciated Mayer’s contributions, he managed that Mayer obtained a position in Princeton where he died of cancer in 1948. Reviewer: A. Kleinert (Halle) Cited in 3 Documents MSC: 01A60 History of mathematics in the 20th century 81-03 History of quantum theory 83-03 History of relativity and gravitational theory Keywords:Dirac equation; epistemology; Walther Mayer Biographic References: Mayer, Walther; Einstein, Albert Citations:JFM 59.0066.04; JFM 60.0686.04; JFM 58.1341.01; JFM 58.1342.01; JFM 58.1343.01; Zbl 0009.03602; Zbl 0007.23302; Zbl 0007.26601; Zbl 0006.22903 PDFBibTeX XMLCite \textit{J. van Dongen}, Arch. Hist. Exact Sci. 58, No. 3, 219--254 (2004; Zbl 1065.01011) Full Text: DOI