Frédéric Bouchard and Philippe Huneman (eds.) From Groups to Individuals: Evolution and Emerging Individuality
Life is not distributed homogeneously on Earth’s surface. Instead, life is clustered into discernible individuals, such as organisms and cells. This happened in part because, at different moments in evolutionary history, free-living individuals merged to form higher-level individuals. Multicellular organisms evolved from single cells; eukaryotic cells evolved from different types of bacteria; and the first cells evolved from self-replicating molecules (Maynard Smith and Szathmary 1995; Calcott and Sterelny 2011). A thorny issue in contemporary biology is to explain how individuals evolved from groups of lower-level individuals. Bouchard and Huneman’s book contains eleven new contributions aimed to advance this issue, written by leading scholars in both philosophy and biology. Their book is divided into three parts: the relation between the concepts of individual and organism; the role of adaptations in the evolution of individuals; and the extent to which collectives, such as beehives, are biological individuals. In what follows, I summarize the main claims made by each of these contributions, but in an order different from the one used in the book. The evolution of eusocial colonies, such as beehives from multicellular organisms, constituted a major transition in individuality. Like multicellular organisms, reproduction in eusocial colonies is controlled by a few members of the group and there is an alignment of interests between the colony and its members. Due to similarities eusocial colonies share with multicellular organisms, some authors claim that eusocial colonies are superorganisms that can bear fitness in the same manner as regular organisms (e.g., Wilson and Sober 1989). Matt Haber (Chapter 9) criticizes different accounts of superorganisms. According to him,