What Matters in (Naturalized) Metaphysics?

Can metaphysics ever really be compatible with science? In this paper, I investigate the implications of the methodological approach to metaphysical theorizing known as naturalized metaphysics. In the past, metaphysics has been rejected entirely by empirically-minded philosophers as being too open to speculation and for relying on methods which are not conducive to truth. But naturalized metaphysics aims to be a less radical solution to these difficulties, treating metaphysical theorizing as being continuous with science and restricting metaphysical methods to empirically respectable ones. I investigate a significant difficulty for naturalized metaphysics: that it lacks the methodological resources to comparatively evaluate competing ontological theories, or even to distinguish adequately between them. This objection is more acute when applied to robust realist versions of naturalized metaphysics, since the realist should be able to say which theory is true of the objective world. If this objection holds, then it seems that the commitment to naturalized metaphysics, or to robust realism about the categories and processes in metaphysics, will have to be relaxed.