Form and Function in Evo-Devo

Abstract

The distinction between form and function has a long and complex history among biologists and philosophers. During some historical periods, the concepts are typically taken to name two distinct but consistent aspects of design. Let us term these compatibilist periods. During other periods it is argued that one member of the pair is more basic, central, or meaningful than the other. Term these adversarial periods. This chapter will begin by discussing adversarial periods and how the form-function dichotomy then plays out against other important biological concepts. The most recent adversarial episode was approximately the final quarter of the twentieth century, when “adaptationist” neo-Darwinists favored function and advocates of what became evo-devo argued for the centrality of form. The conflict was often labeled “adaptation versus developmental constraint.” By the turn of the century, advances in molecular developmental genetics and paleontology led to advances in evo-devo (though not necessarily to a reduction in the status of adaptationist studies). The chapter will conclude with a report on the kind of compatibilism that has resulted. Classical texts that had supported earlier adversarial views have received criticism, and functional analyses have come to be applied to the mechanisms of genetics. The strict separation of form and function seems to be dissolving. New philosophical work on the form-function relation is called for.