Darwinian metaphysics: Species and the question of essentialism

Biologists and philosophers of biology typically regard essentialism about species as incompatible with modern Darwinian theory. Analytic metaphysicians such as Kripke, Putnam and Wiggins, on the other hand, believe that their essentialist theses are applicable to biological kinds. I explore this tension. I show that standard anti-essentialist considerations only show that species do not have intrinsic essential properties. I argue that while Putnam and Kripke do make assumptions that contradict received biological opinion, their model of natural kinds, suitably modified, is partially applicable to biological species. However, Wiggins' thesis that organisms belong essentially to their species is untenable, given modern species concepts. I suggest that Putnam's, Kripke's and Wiggins' errors stem from adopting an account of the point of scientific classification which implies that relationally-defined kinds are likely to be of little value, an account which is inapplicable to biology.