The class struggle, to which Marx has specially drawn attention, is a real factor, the tokens of which are to be found on every page of history. But the struggle is not confined only to two classes: the proletariat and the capitalist; it occurs between an infinite number of groups with different interests, and above all between the elites contending for power. The existence of these groups may vary in duration, they may be based on permanent or more or less temporary characteristics. In the most savage peoples, and perhaps in all, sex determines two of these groups.
