The normative account: is it possible for anything naturalistic in character to have normative value?
Locke’s real and nominal essences are used to discuss natural kinds. Locke’s view on natural kinds shoots in three seperate directions: conventionalist (classification convenient and not accurate) , realist ‘light’ (Locke’s official position; that there are real kinds, though real essences unknowable), and realist (kinds are known with difficulty).
Realism: there are individual things in nature. There are also real kinds of things. They exist, and hence we can discover them. We do not construct them or imagine them. They are real divisions found in nature. Kornblith points out that create categories, which can be accurate/inaccurate or useful/not-useful, but there are real divisions. Such as mammals, further divided into cats and dogs, and into ever smaller categories. Conventionalism suggests that individual things in the world are real, but kinds are not. Categories are a human construct. The classification system is all important.