 The structure of Davidson’s derivation of the token-identity of causally interacting mental events with physical events appears to be straightforward: causally interacting mental events (the interaction principle) must instantiate some strict law property (the cause-law principle) but mental properties are not suitable for inclusion in strict laws (the anomalism principle). So mental events must instantiate some other property, which is suitable for such inclusion. Given Davidson’s invocation of the causal closure of the physical domain, according to which every physical event has a physical explanation, he moves rather quickly to the conclusion that this other property must be physical, since closure entails that physical properties have a privileged status, which suggests that they hold out the promise of strict laws. (Davidson also has a tendency simply to identify as ‘physical’ those properties that figure in strict laws (Davidson 1970, 224; 1995a, 266), but this would of course beg the question of mental anomalism.) Consequently, causally interacting mental events must be token-identical with physical events, ruling out Cartesian as well as other forms of dualism.