  There is no doubt that with regard to the general theory of  relativity, Weyl held strong philosophical views. Some of these views are couched in a phenomenological language and reveal Husserl’s  influence on Weyl. Ryckman’s (2005) study The Reign of Relativity provides an extensive account of Weyl’s orientation to Husserl’s phenomenology. On the other hand, many of Weyl’s philosophical views  are couched in an unequivocal empiricist-realist language. For  example, Weyl rejected Poincaré’s geometrical conventionalism  and forcefully argued that the spacetime metric field is physically  real, that it is a physically real structural field (Strukturfeld),  which is determined by the physically real causal (conformal)  structure and the physically real inertial (projective) structure or  guiding field (Führungsfeld) of spacetime. He was not deterred  in putting forward such ontological claims about the metric structure of spacetime despite the fact that a complete epistemologically  satisfactory solution to the measurement problem for the spacetime  metric field was not then available. In the same manner, Weyl  forcefully advanced a field-body-relationalist ontology of spacetime  structure. He argued that a Leibnizian or Einstein-Machian form of  relationalism that is based on a pure body ontology, is not tenable,  indeed is incoherent within the context of general relativity, and he presented a reductio argument, the plasticine example, to  underscore the necessity of the existence of a physically real  guiding field in addition to the existence of bodies. 