 By the winter of 1919–1920, for both physical and philosophical reasons (the latter having to do with his largely positive reaction to Brouwer’s intuitionist views about the mathematical continuum, in particular, the continuum of spacetime—see Mancosu &amp; Ryckman 2005), Weyl (1920) surrendered the belief, expressed here, that matter, with its corpuscular structure, might be derived within spacetime geometry. Thus he gave up the Holy Grail of the nascent unified field theory program almost before it had begun. Nonetheless, he actively defended his theory well into the 1920s, essentially on the grounds of Husserlian transcendental phenomenology, that his geometry and its central principle, “the epistemological principle of relativity of magnitude” comprised a superior epistemological framework for general relativity. Weyl’s postulate of a “pure infinitesimal” non-Riemannian metric for spacetime allowed the “gauge” (by which Weyl meant a scale of length; the term has a different meaning today) to vary at each spacetime point. But it met with intense criticism. No observation spoke in favor of it; to the contrary, Einstein pointed out that according to Weyl’s theory, the atomic spectra of the chemical elements should not be stable, as indeed they are observed to be. Although Weyl responded to this objection forcefully, and with some subtlety (Weyl 1923a), he was able to persuade neither Einstein, nor any other leading relativity physicist, with the exception of Eddington. However, the idea of requiring gauge invariance of fundamental physical laws was revived and vindicated by Weyl himself in a different form later on (Weyl 1929; see Ryckman 2005: chs. 5 &amp; 6; O’Raifeartaigh 1997; Scholz 2001, 2004; Afriat 2017, Other Internet Resources).