"For understandable, if philosophically frivolous, reasons the collapse of the Soviet Union has been taken - especially in the media - as signaling the defeat of Marxism qua philosophy", so writes Leiter in Hermeneutics of Suspicion. The irony is that this frivolity is particularly fitting considering Marx's own stance:“The philosophers have only interpreted the world, in various ways. The point, however, is to change it", and the Soviet Union failed to change it (for the better). This however is too clever by half, Leiter also points out another irony:"the Soviet Union arguably collapsed for Marxian reasons: bureaucratic central planning clearly fettered the development of the forces of production, and thus was eventually supplanted by nascent market forms of production and distribution".
A staple of Marxism is the "historical materialism", the claim that on a grand scale the course of history is ultimately determined by material resources and means of production, and economic constraints they impose on societies. Interestingly, Marx is not a determinist, his other staple "dialectical materialism" explicitly condemns mechanical determinism, his is more of a big picture fatalism. Material causes do not predetermine history in every detail, but they do its "essential" features in the fullness of time. The rest, individuals, ideas, cultures, ideologies are superficial decorations shaped and dragged along by economic undercurrents.
Leaving aside political activism and utopian millenarianism what of the philosophical content? As materialisms go, Marx's is arguably more nuanced than plain physicalism. And it is hard to miss affinities with the recent "geography is destiny" school of thought, e.g. Diamond's Guns, Germs and Steel, or the earlier incarnation in Adams's Energy and Structure:"Diamond's central conception is that the course of history, broadly speaking, is not determined by individual actions, cultural factors, or racial differences, but by the environmental circumstances into which different groups of people accidentally wandered".
I know the usual maneuver is to place the burden of proof on a Marxist, and claim (rightly) that a case for material determination of history has not been made. But are there good arguments that it can not be made, that historical materialism (and not just Marx's social prescriptions) is philosophically indefensible and/or empirically discredited?