Locke and Natural Kinds

Locke famously wrote that ‘Men make sorts of Things’ by which he is often taken to mean that people rather than nature divide up the world into species: real essences or inner structures of things do not determine the boundaries of species; species are made by us when we select a set of qualities which we regard as essential for species-membership. In recent scholarship this reading has been questioned. According to these scholars, Locke is a realist, who assumes the existence of real essences shared between individuals of the same species. These shared essences can explain why we see stable, well-delineated and objective differences and similarities in nature. This paper argues that this recent line of interpretation weakens the radical nature of Locke’s central message. It defends a conventionalist interpretation, arguing that on Locke’s own understanding of essence, species, and classification, he cannot be a realist about natural kinds.