Ernest Gellner made major contributions in very diverse fields, notably philosophy and social anthropology. His attacks on the orthodoxies of his time made it difficult for him to be fully accepted into either of these academic communities, but that suited him well enough: he seemed to enjoy leading a one-man crusade for critical rationalism, defending enlightenment universalism against the rising tides of idealism and relativism. His influence spread far beyond social anthropology: the fierce tone of the polemics of the 1950s against Oxford philosophers was repeated during the 1990s in tangles in the TLS with the literary critic Edward Said. For Gellner the issues were essentially the same: the vital need to refute the claim that ideas lead the world.