What role, if any, i s there for conceptual analysis in metaphysics? On the face of it, very little. Metaphysics is to do with what is in the world and what it is like, not with concepts and semantics. 1 We would expect science in the wide sense to be highly relevant, but not the armchair deliberations of the philosopher concerned with the analysis of concepts. However, traditionally metaphysi cians have paid at least as much attention to questions of conceptual analysis, and to related questions of logical intercon nections (to what entails or fails to entail what) as they have to what science tells us about the world. David Armstrong, for example, while rightly and famously insisting that what is said in the philosophy of mind must be answerable to what science tells us about the role of the brain in the causation of behaviour, spends most of A Materialist Theory of the Mind doing concep tual analysis.2 It is understandable that recently many philoso phers writing under the banner of 'naturalism' have declared the traditional preoccupations of metaphysicians with such armchair matters as conceptual analysis and entailments to be a mistake.