Thoughts often cause deeds. Actions are done for reasons. But do actions and their mental causes also have descriptions that do not involve reasons? Various considerations can make it seem that human mental events must be biochemical events. Paul Pietroski, however, defends a non-Cartesianform of dualism. Actions and their rationalizing causes belong to an autonomous mental domain-although this autonomy is compatible with the supervenience of the mental on the non-mental. On this view, some bodily motions have rationalizing causes distinct from any biochemical causes; Pietroskiargues that this is not an objectionable form of overdetermination. Central to his account is his proposed treatment of ceteris paribus laws, their role in explanation, and how such laws are related to singular causal claims. Pietroski also connects these issues to semantic questions arising fromdiscussions of action reports and belief ascriptions. All philosophers interested in mind or causation will be intrigued by his new theory.