One hotly debated philosophical question in the analysis of evolutionary theory concerns whether or not evolution and the various factors which constitute it may profitably be considered as analogous to “forces” in the traditional, Newtonian sense. Several compelling arguments assert that the force picture is incoherent, due to the peculiar nature of genetic drift. I consider two of those arguments here – that drift lacks a predictable direction, and that drift is constitutive of evolutionary systems – and show that they (...) both fail to demonstrate that a view of genetic drift as a force is untenable. I go on to diagnose the reasons for the stubborn persistence of this problem, considering two open philosophical issues and offering some preliminary arguments in support of the force metaphor. (shrink)

In this article we focus on the emergence of biological individuality by association, trying to formulate some theoretical conditions to think about the process of collective individualization. The starting point of our analysis is the notion of “major evolutionary transition.” A major evolutionary transition is the result of the integration of a multiplicity of initially independent biological entities that, by managing to organize their interactions, become a collective of components having an identity oriented towards a common goal. When biological organisms (...) are concerned, a major transition corresponds to a phenomenon of fusion between them. We shall argue that the emergence of a new biological level of individuality implies the establishment of constitutive relationships between individuals that change their status as autonomous entities. As a result, the emergence of a new type of entity in the living world implies that individuals enter into relationships that intrinsically transform them, a transformation sufficient for a “whole” to become a “part” that forms another “whole”, that is, a new level of organismality. (shrink)

The group selection controversy largely focuses on altruism (e.g., Wilson 1983; Lloyd 2001; Shavit 2004; Okasha 2006, 173ff; Borrello 2010; Leigh 2010; Rosas 2010; Hamilton and Dimond in press). Multilevel selection theory is a resolution of this controversy. Whereas kin selection partitions inclusive fitness into direct and indirect components (via influencing the replication of copies of genes in other individuals), multilevel selection considers within-group and between-group components of fitness (Gardner et al. 2011; Lion et al. 2011). Two scenarios of multilevel (...) selection are often distinguished (Damuth and Heisler 1988; Okasha 2006; Pigliucci 2010): (1) group structure only divides individual fitnesses into within- and between-group components (MLS1); and, (2) groups get their own component of fitness and also, in most definitions, a group-level adaptation (MLS2). (shrink)