In the debate on the units of selection, the controversy about the possibility of genuinely altruistic behavior has a prominent place. By assuming a pluralistic position, some relevant issues on the topic will be discussed in this paper. Firstly, altruism will be conceived as a phenotypic property of biological groups, not just of their members. Secondly, this characterization will be applied to the discussion on the relationship between groups in complex societies, as humans ones. In that context, a model about how altruistic and egoistic behaviors overlap at different levels of social dynamics will be outlined. Finally, a method aimed at determining what kinds of evolutionary forces influence behavior in empirical cases will be suggested.
Egoism; Altruism; Interactors; Unities of selection; Populations
