Mineral misbehavior: why mineralogists don’t deal in natural kinds

Abstract

Mineral species are, at first glance, an excellent candidate for an ideal set of natural kinds somewhere beyond the periodic table. Mineralogists have a detailed set of rules and formal procedure for ratifying new species, and minerals are a less messy subject matter than biological species, psychological disorders, or even chemicals more broadly—all areas of taxonomy where the status of species as natural kinds has been disputed. After explaining how philosophers have tended to get mineralogy wrong in discussions of natural kinds, I show how minerals species don’t behave like natural kinds. They are defined on the basis of human intentionality, not merely natural distinctions. They aren’t ideal grounds for inductive inference. And they don’t form a system that divides nature along a set of equivalent joints. While this is a regrettable outcome to those of us who like the idea of science relying on natural kinds, I contend that mineralogy is doing just fine without a natural kind-based taxonomy, and may in fact be better off without one.