The method of Conceptual Analysis makes use of natural language speaker intuitions about the meanings of expressions, and relies on an externalist assumption about meanings—namely, that they can be given in terms of referential relations and truth. This article argues that this widely used methodology in metaphysics is troubled, because the assumed externalist hypothesis about natural language meanings is beset with trenchant obstacles in explaining linguistic phenomena. It argues that the use of Conceptual Analysis in metaphysical investigation inherits the difficulties (...) for the externalist hypothesis generally assumed by metaphysical inquiry. It explores two cases of such investigation that serve to exemplify the breadth of topics susceptible to troubles with the externalist hypothesis regarding natural language meanings: the extended mind hypothesis and the metaphysics of causation. (shrink)