Abstract

1. IntroductionIn What Biological Functions Are and Why They Matter, Justin Garson offers a novel theory of biological functions, the generalized selected effects (GSE) theory.1 He presents the theory in a clear and comprehensive way, defends it against various objections and applies it to different areas of philosophy, including the philosophy of psychiatry, the debate about mechanisms and the debate about teleosemantic theories of mental content.2Like other proponents of the aetiological approach to functions, Garson maintains that a trait’s biological functions are grounded in its selectional history. However, his GSE theory differs from standard versions of the aetiological approach – so-called selected effects (SE) theories – in a crucial respect: while SE theories assume that all biological functions must ultimately be grounded in phylogenetic processes of natural selection or other (closely analogous) processes of differential reproduction (Millikan 1984: 15–82, Neander 1991, Godfrey-Smith 1994), the GSE theory allows that functions may also be grounded in processes of differential retention (see §2 for details). Garson forcefully argues that this broader account is theoretically well-motivated and has significant advantages over standard SE accounts when it comes to accommodating certain important classes of ontogenetically determined functions.