The viability of a way of life, we have argued in Part 1, depends on its generating practices, values, and beliefs that in turn legitimize its pattern of social relations. We have, moreover, identified five viable ways of matching social relations with cultural biases and shown how, for all their ineradicable antagonisms, these ways of life ultimately depend on one another. In Part 2, we ask how our theory of viability (both its typology and its mode of explanation) compares with those offered by the past greats of sociological theory.