All societies contain some image or vision of their own perfection—of life, both individual and collective, free of the burdens of history and death. In the history of civilizations, these visions have often served as a fulcrum of radical change and social transformation. Just as often, they have served as the ideological underpinnings of more abortive movements of social change. Moreover, in the lives of individuals and groups, they have often led to a renunciation of the world and its concerns in search of a more private wholeness, in a life of contemplation and retreat.