Why does the problem of free will seem so intractable? I surmise that in large measure it does so because the free will debate, at least in its modern form, is conducted in terms of a mistaken approach to causality in general. At the heart of this approach is the assumption that all causation is fundamentally event causation. Of course, it is well-known that some philosophers of action want to invoke in addition an irreducible notion of agent causation, applicable only in the sphere of intelligent agency. But such a view is generally dismissed as incompatible with the naturalism that has now become orthodoxy amongst mainstream analytical philosophers of mind. What I want to argue is that substances, not events, are the primary relata of causal relations and that agent causation should properly be conceived of as a species of substance causation. I shall try to show that by thus reconceiving the nature of causation and of agency, the problem of free will can be made more tractable. I shall also argue for a contention that may seem even less plausible at first sight, namely, that such a view of agency is perfectly compatible with a volitionist theory of action.