This essay aims to provide an account of the differences between what I call the “Classical Marxist” conception of science which was adhered to by Marx and Engels and further developed by Boris Hessen and others on the one hand, and the conception of science which characterizes “Western Marxism” as it developed through the work of the theorists of the Frankfurt School on the other hand. I argue that Western Marxists such as Herbert Marcuse and Max Horkheimer did not in (...) fact successfully criticize the logical positivist account of the modern natural sciences. Instead I argue that they implicitly accepted the positivists’ characterization of the modern natural sciences (as they interpreted it) and then proceeded to devalue the modern natural sciences on this basis. I also show that Marcuse and Horkheimer, even though they presented themselves as revolting against the alleged “economism” of Classical Marxism, ended up endorsing a view of science which is functionally equivalent to a reductive economistic conception of science. I argue that the Classical Marxists’ conception of science is far richer and far more interesting than either a stereotyped “economistic” conception of science or the Western Marxist conception of modern science as merely an element in a historical process centered on the oppressive universalization of instrumental reasoning. (shrink)