1. Rather than adopting the self-categorization argument that interest in the group’s welfare involves an extension of self-interest based on recategorization of self at the group level (Turner, 1987), one might argue that interest in the group’s welfare reflects enlightened self-interest (see Batson, 1994). Or one might argue—contrary to the value assumption of the theory of rational choice—that the group’s interest is valued as an end in itself, distinct from self-interest. At times, Dawes and his colleagues seem to adopt the self-categorization argument; at times, the group-interest argument (see Dawes et al., 1988, 1990). Insofar as I know, there is at present no clear evidence to support one of these arguments over the other. Indeed, each might be true under different circumstances. Therefore, I shall remain agnostic on the ultimate goal of motivation to uphold the common good. When in later sections I juxtapose this motive to egoism, the juxtaposition is to individual material self-interest. Upholding the common good could be produced by (1) a special form of egoism in which self-interest is redefined at the group level, (2) enlightened self-interest (e.g., pursuit of side payments), or (3) a motive, distinct from egoism, with the ultimate goal of increasing the group’s welfare (I have called this last motive “collectivism”—Batson, 1994).