  The underlying motivation for assumption \(\mathbf{C}\) of physical causality is essentially Mach’s empiricist programme, namely, Mach’s insistence on the primacy of observable facts of experience. Addressing Einstein’s formulation of Mach’s paradox, Weyl (1924b) says: Only if we conjoin the kinematic principle of relative motion with the physical assumption \(\mathbf{C}\) does it appear groundless or impossible on the basis of the kinematic principle that in the absence of any external forces a stationary body of fluid has the form of a sphere “at rest”, while on the other hand it has the form of a “rotating” flattened ellipsoid. Weyl rejects principle \(\mathbf{C}\) of physical causality because he denies the feasibility of \(\mathbf{M}\) (Mach’s Principle), as defined above, on \(a\)  priori[69]  grounds. According to Weyl (1924b) 