The evolution of altruism and the units of selection problem

Abstract

In this paper, I will address one of the main issues in the philosophy of biology: the evolution of altruism and cooperation and the related problem of the units of selection. Starting from the so-called paradox of altruism, I will critically examine standard evolutionary models for the resolution of that paradox, and the explanation of altruism. I review and assess the following models of selection: the traditional model of group selection, gene?s eye view, kin selection, direct reciprocity (reciprocal altruism), indirect reciprocity, and the updated version of group selection, namely Sober and Wilson?s model of multilevel selection. In the final section, I will try to explain why is the dismissal of multilevel selection based on its explanatory complexity so common, and why inclusive fitness theory and direct reciprocity are generally sufficient to explain a good part of biological phenomena related to altruism and cooperation.