 On this interpretation of Marxism, the philosophical presupposition of Marx and Engels which were identified as dialectical materialism were incompatible with the delineation of Marxism as a scientific and experimental hypothesis. Thus, while, or even because Hook asserted his belief in a version of Marxism as compatible with pragmatism as an experimental hypothesis, the various theses of Marxist dialectical materialism were subjected to an intensely probing and extremely skeptical criticism in his writings. Consequently, Hook found himself to be identified as a supporter of Marxism through an unorthodox interpretation of that theory, while at the same time he was castigated as an opponent of Marxism by the recognized authoritative figures of the Marxist movement because of his severe criticism of the metaphysical claims within the Marx-Engels canon regarding dialectical materialism. Hook’s interpretation of Marxism as a scientific hypothesis would appear to be compatible with the Marxist movement’s preferred characterization of its theory as “scientific socialism” in opposition to “utopian socialism.” Yet, scientific socialism was asserted by its followers to be a species of ultimate philosophical truth rather than, as Hook’s pragmatic interpretation required, a set of fallible and corrigible hypotheses about the historical situation, including contemporaneous economic processes and their eventual outcomes. It was evident to believers in Marxism as a kind of secular faith or religion that its interpretation as a species of experimental science left the way open for its refutation and revision or rejection in light of the analysis of future consequences. For Marxists, and to a significant degree for Hook, in the early 1930s Marxism was a commitment of faith and a normative guide to revolutionary action. Yet as an experimental theory according to Peircian pragmatic principles, it would admit of “disconfirmation” or refutation in the light of future historical evidence. From this perspective, in the context of the 1920s, the empirical nature of the institutions of the socialist society in the Soviet Union and their development in the near future could be identified as representing factors that would confirm or refute the Marxist hypothesis.