Because anthropology describes the observed range of human variation, as well as constants in human life, it is inextricably linked to the project of describing what is possible for a revolution to achieve. This episode examines cross-cultural universals, technological thresholds, and hierarchies. We assess the notion that small, egalitarian societies are such because they consciously subdue the impulse to domination, that there is no fundamental discontinuity between "traditional" and "modern" people, and that traditional societies, also, were shaped by social movements.