Abstract

‘Natural kind essentialism’—here defined as the view that (i) the existence of natural kinds is a mind- and theory-independent matter, (ii) their essences are intrinsic, and (iii) they have a hierarchical structure—is commonly thought to be justified by appeal to Kripke–Putnam semantics, according to which propositions like ‘water is H20’ are necessary a posteriori. This chapter argues that the Kripke–Putnam semantics is in fact compatible with the denial of each of the three tenets of natural kind essentialism. The basic argument is that, assuming the range of natural kinds goes beyond those kinds for which we have vernacular names, deference to scientific theories is required in fixing the reference of natural kind terms. That those theories describe mind- and theory-independent reality, and that they do not admit a non-hierarchical structure for the categories they deploy, are theses that are independent of anything derivable from Kripke–Putnam semantics itself.