Debates over the nature of human nature have characterized social theory since it emerged in the Renaissance. As Thomas Sowell has argued, these debates generally take two forms: the optimistic and the pessimistic (Sowell 1987). The former position, associated with Rousseau and anarchists such as William Goodwin, holds that humans are essentially good but are turned bad by the institutions of their society. The latter position is rooted in the assumption that humans are fundamentally egoistic and selfish, thereby requiring either a strong state to regulate them or, in a less pessimistic account, an institution like the market to guide their affairs toward an optimal result.

For sociologists, neither position became the dominant way of thinking about human nature; instead, the plasticity of human experience was emphasized. Durkheim (1973) wrote the most important defense of a pluralistic approach to the subject, one that remains unsurpassed to this day...