Resurrecting Biological Essentialism

Abstract The chapter defends the doctrine that Linnaean taxa, including species, have essences that are partly intrinsic underlying, probably largely genetic, properties. The consensus among philosophers of biology is that such essentialism is deeply wrong, indeed incompatible with Darwinism. I argue that biological generalizations about the morphology, physiology, and behavior of species require structural explanations that must advert to these essential properties. The objection that, according to current “species concepts”, species are relational is rejected. These concepts are primarily concerned with what it is for a kind to be a species and throw little light on the essentialist issue of what it is for an organism to be a member of a particular kind. Finally, the chapter argues that this essentialism can accommodate features of Darwinism associated with variation and change. In particular, essentialism can accept gradual change and a certain indeterminacy about species.