Volume 27, 2002
Christopher Hughes Conn
Locke on Natural Kinds and Essential Properties
The two opinions concerning real essences that Locke mentions in III.iii.17 represent competing theories about the way in which naturally occurring objects are divided into species. In this paper I explain what these competing theories amount to, why he denies the theory of kinds that is embodied in the first of these opinions, and how this denial is related to his general critique of essentialism. I argue first, that we cannot meaningfully ask whether Locke accepts the existence of natural kinds, per se, since he affirms the theory of kinds that is embodied in the second opinion, while he denies the theory that is embodied in the first opinion. Second, I show that his denial of this theory is not solely or even primarily directed against the scholastic/Aristotelian theory of substantial forms, since he is most interested in refuting a corpuscularian version of this theory. And third, I argue that Locke’s anti-essentialism does not follow solely from his denial of (deeply objective) natural kinds, since one could consistently make this denial and affirm the existence of de re essential properties.