This dissertation draws on the Aristotelian and contemporary communitarian belief that humans are socially constituted, and analyzes the manifestations of this belief in contemporary identity politics and in the concept of 'culture' that often underlies identity politics. While I argue that it is important to maintain a communitarian conception of the self, I depart from Aristotle and the communitarian tradition by rejecting the assumption that a constitutive community is characterized by unity and homogeneity. I then claim that identity politics has (...) inherited both the virtues and the problems of communitarian theory. Just as communitarians claim that the self is never free from social constitution, so identity politics have taken the self's identity to be formed along lines of socially defined group differences, and like communitarianism, some identity politics has entailed a call for unity. In the case of identity politics, the requirement for membership in the community may be sharing certain essential characteristics of identity; difference can result in marginalization, forced assimilation to the group norm, or expulsion. Because identity politics often relies upon the concept of 'culture' to ground group identities, I also examine this concept. When a community's unity derives from its members understanding themselves to share a culture, the maintenance of the culture itself can be conservatizing; the culture can remain closed off from changes as it preserves the "traditional" or "authentic"; furthermore, it can come to be treated as an object outside of the people who live it and as such the changing lived realities of these people--particularly changes that cross lines of identity--do not serve to continually offer new, changing, and ambiguous ways of conceiving of what is shared between members of the community. I argue for the development of group identity that recognizes intersecting group differences, and can permit hybridity or mixed identities. I end by suggesting that for a constitutive community to remain truly constitutive without harming its members through marginalization, forced assimilation to a norm or a shared essence, or stagnation, members must give up the sort of control that maintains the community as a unity. (shrink)