Recent trends in the debate about natural kinds tend towards increasingly permissive and practice-oriented views. I argue that while these accounts—which I characterize using Boyd’s ([1991]) term ‘enthusiasm’—offer several helpful insights, they often lack the normative force that they want to have; that is, they cannot provide an account of what makes something a good or bad, better or worse, kind for scientific pursuits. I argue that such accounts can regain a minimal sense of normativity in two ways. The first, (...) which has already been widely embraced by theorists, is to index the appropriateness of a scientific kind to the domain within which it is situated. While this is a good solution, it is not clear how it can be applied in interdisciplinary and cross-domain research pursuits, which are increasingly common. The second way of regaining normativity—which is especially, but not exclusively, effective for such cross-domain pursuits—is to attend to the stage at which scientific research is occurring. (shrink)

Metaphysical investigation often proceeds by way of linguistic meaning. This tradition relies on an assumption about meanings, namely that they can be given in terms of referential relations and truth. Chomsky and others have illustrated the difficulty with this externalist hypothesis regarding natural language meanings, which implies that natural languages are ill‐suited for the purposes of metaphysical investigation. In reply to this discordance between the features of natural languages and the goals of metaphysical investigation, metaphysicians propose that we look to (...) the invented languages used to express our best scientific theories as metaphysical guides, in the hope that these languages are better behaved. I argue that this retreat is beset with similar troubles for the metaphysician. In particular, I argue that central terms in the field of biology, namely ‘gene’ and ‘species’, exhibit a kind of lexical flexibility that renders them, much like their natural language counterparts, ill‐suited for the metaphysician's aims. (shrink)