Abstract

The traditional home for the concept of a natural kind in biology is of course taxonomy, the sorting of organisms into a nested hierarchy of kinds. Many taxonomists and most philosophers of biology now deny that it is possible to sort organisms into natural kinds. Many do not think that biological taxonomy sorts them into kinds at all, but rather identifies them as parts of historical individuals. But at any rate if the species, genera and so on of biological taxonomy are kinds at all, there are various respects in which they fall short of the traditional requirements of naturalness. The members of biological taxa lack essential properties that make them members of a particular kind: any properties specific enough to belong only to members of the kind cannot be assumed to belong to all members of the kind. And if there are laws applying to members of biological taxa they are laws of very minor and local importance and, in view of the preceding point, at best probabilistic.