 However, this implied reduction of physics to geometry was crucially obtained within the epistemological frame of what Hilbert termed “the axiomatic method”; its intended significance is that of a proposed solution to the 6th (“the axiomatization of physics”) of the famous 23 mathematical problems posed by Hilbert at the 1900 International Congress of Mathematicians in Paris (Brading &amp; Ryckman 2008). Others pursued a different path, seeking the reduction of physics to geometry by generalizing beyond the pseudo-Riemannian geometry (a Riemannian geometry distinguishing between space and time dimensions) of general relativity (Hermann Weyl, Arthur Stanley Eddington) or by employing Riemannian geometry in five dimensions (Theodore Kaluza). Whatever may have been Kaluza’s philosophical motivations (van Dongen 2010: 132–5), neither mathematical realism nor Platonism played a role in Weyl’s (1918a,b), and following Weyl, Eddington’s (1921) generalizations of Riemannian geometry. Their proposals were above all explicit attempts to comprehend the nature of fundamental physical theory in the light of general relativity, from systematic epistemological standpoints neither positivist nor realist. As such they comprise early philosophical interpretations of that theory, although they intertwine philosophy, geometry and physics in a manner unprecedented since Descartes.