[...] If you go back to the early formulations of historical materialism, what Marx always talks about is the way in which social and cultural structures overdetermine the natural ones. Marx is aware that we remain natural beings, that we remain in nature. What he’s talking about is the elaborations of social and cultural organization which complete those natural structures. Our genetic constitution is extraordinarily open-ended and is thus a necessary but not sufficient way of becoming human. What is happening, historically, is the massive complexification of the social, the overdetermination of the natural by the social and cultural. So Nature can no longer stand as the ultimate guarantee of materialism. Already in the nineteenth century, Marx polemicized against that kind of vulgar materialism but there was, and still is, a sense in which orthodox Marxists think that something is ultimately only real when you can put your hands on it in Nature. We can’t be materialists in that way any longer. But I do think that we are still required to think about the way in which ideological/cultural/discursive practices continue to exist within the determining lines of force of material relations, and the expropriation of nature, which is a very different question. Material conditions are the necessary but not sufficient condition of all historical practice. Of course, we need to think material conditions in their determinate discursive form, not as a fixed absolute. I think the discursive position is often in danger of losing its reference to material practice and historical conditions.