Evolutionary theorists often talk as if natural selection were choosing the most adapted traits, or if organisms were deciding to do the most adaptive strategy. Moreover, the payoff of those decisions often depend on what others are doing, and since Hamilton (1964), biologists possess conceptual tools such as kin selection and inclusive fitness to make sense of outcomes of evolution in these contexts, even when they seem unadaptive (such as sterility). The link between selection and adaptation through which selection or organisms can be seen as agents, as well as the scope and nature of Hamiltonian conceptions of social evolution, stimulated many formal elaborations (such as, initially, Fisher’s “Fundamental theorem of natural selection”), but also raise major philosophical issues about causation and statistics, and about rationality and adaptation or selection. Two recent philosophy books, Okasha’s Agents and goals in evolution, and Birch’s Philosophy of social evolution, tackle those question. This essay reflects on them in order to think of those two issues. After having reviewed the books, I try to sketch some philosophical lessons onto which they concur.
