 The emphasis on the continuity and coherence in the development of Einstein’s philosophy of science contrasts with an account such as Gerald Holton’s (1968), which claims to find a major philosophical break in the mid-1910s, in the form of a turn away from a sympathy for an anti-metaphysical positivism and toward a robust scientific realism. Holton sees this turn being driven by Einstein’s alleged realization that general relativity, by contrast with special relativity, requires a realistic ontology. However, Einstein was probably never an ardent “Machian”  positivist,[1]  and he was never a scientific realist, at least not in the sense acquired by the term “scientific realist” in later twentieth century philosophical discourse (see Howard 1993). Einstein expected scientific theories to have the proper empirical credentials, but he was no positivist; and he expected scientific theories to give an account of physical reality, but he was no scientific realist. Moreover, in both respects his views remained more or less the same from the beginning to the end of his career.