A popular response to the Exclusion Argument for physicalism maintains that mental events depend on their physical bases in such a way that the causation of a physical effect by a mental event and its physical base needn’t generate any problematic form of causal overdetermination, even if mental events are numerically distinct from and irreducible to their physical bases. This paper presents and defends a form of dualism that implements this response by using a dispositional essentialist view of properties to argue that the psychophysical laws linking mental events to their physical bases are metaphysically necessary. I show the advantages of such a position over an alternative form of dualism that merely places more “modal weight” on psychophysical laws than on physical laws. The position is then defended against the objection that it is inconsistent with dualism. Lastly, some suggestions are made as to how dualists might clarify the contribution that mental causes make to their physical effects.