The assumption that, beneath economics, reality is psychosexual is often rejected as ahistorical by those who accept a dialectical materialist view of history because it seems to land us back where Marx began: groping through a fog of utopian hypotheses, philosophical systems that might be right, that might be wrong (there is no way to tell); systems that explain concrete historical developments by a priori categories of thought; historical materialism, however, attempted to explain 'knowing' by 'being' and not vice versa.