The concept of class has greater explanatory ambitions within the Marxist tradition than in any other tradition of social theory and this, in turn, places greater burdens on its theoretical foundations. In its most ambitious form, Marxists have argued that class – or very closely linked concepts like “mode of production” or “the economic base” – was at the center of a general theory of history, usually referred to as “historical materialism.” This theory attempted to explain within a unified framework a very wide range of social phenomena: the epochal trajectory of social change as well as social conflicts located in specific times and places, the macro-level institutional form of the state along with the micro-level subjective beliefs of individuals, large-scale revolutions as well as sit-down strikes. Expressions like “class struggle is the motor of history” and “the executive of the modern state is but a committee of the bourgeoisie” captured this ambitious claim of explanatory centrality for the concept of class.

Most Marxist scholars today have pulled back from the grandiose explanatory claims of historical materialism (if not necessarily from all of its explanatory aspirations). Few today defend stark versions of “class primacy.” Nevertheless, it remains the case that class retains a distinctive centrality within the Marxist tradition and is called upon to do much more arduous explanatory work than in other theoretical traditions.