In this paper, we argue that, in order to account for the apparently substantive nature of definitional disputes, a commitment to what we call ‘Socratic essentialism’ is needed. We defend Socratic essentialism against a prominent neo-Carnapian challenge according to which apparently substantive definitional disputes always in some way trace back to disagreements over how expressions belonging to a particular language or concepts belonging to a certain conceptual scheme are properly used. Socratic essentialism, we argue, is not threatened by the possibility (...) that some apparently substantive definitional disputes may turn out to be verbal or conceptual, since this pluralist strategy, in our view, requires a commitment to more, rather than fewer, essences. What is more, a deflationary, metaphysically ‘light-weight’ construal of the essence-ascriptions in question leads to a peculiar conception of the pursuit of metaphysicians as behaving like deceptive (or self-deceived) grammarians pretending to be scientists. Moreover, this deflationary attitude, we argue, spreads beyond metaphysics and philosophy more broadly to apparently substantive definitional disputes in the sciences as well as other in other disciplines, such as art criticism. (shrink)