  Einstein (1916) argued that the general theory of relativity removes  from the special theory of relativity and Newton’s theory an inherent epistemological defect. The latter is brought to light by Mach’s  paradox, namely, Einstein’s example of two fluid bodies, \(A\) and \(B\), which are in constant relative rotation about a  common axis. With regard to the extent to which each of the spheres  bulges at its equator, infinitely many different states are possible  although the relative rotation of the two bodies is the same in every case. Einstein considered the case in which \(A\) is a sphere and  \(B\) is an oblate spheroid. The paradox consists in the fact that there is no readily discernible reason that accounts for the fact  that one of the bodies bulges and the other does not. According to  Einstein, an epistemological satisfactory solution to this paradox  must be based on ‘an observable fact of experience’.  Einstein wanted to implement a Leibnizian-Machian relational  conception of motion according to which all motion is to be  interpreted as the motion of some bodies in relation to other bodies. Einstein wished to extend the body-relative concept of uniform  inertial motion to the concept of a body-relative accelerated motion. 