Abstract

Although generally informed by an intimate knowledge of evolutionary biology and taxonomy, the controversy over the nature of species is clearly philosophical; it consists almost entirely of the clarification of old, and the invention of new arguments for or against calling the species category a class, The debate seems firmly divided between those, like Kitts and Bernier, who see homo sapiens as a class, and those, like Hull and Ghiselin, who see it as an individual. In the first case, particular human beings are members; in the second case, parts. To the champions of class, the essentialists, each species can be defined by means of a unique set of necessary and sufficient conditions, and every organism can be placed without equivocation into a particular species. To the individualists, nothing could be further from the truth. As a contingent, product of evolution, each species shares that crucial characteristic of an individual, spacio-temporal identity; each is a chunk of genealogical nexus.