  Cartesian dualism has fallen out of favor among philosophers and cognitive scientists. There are, to be sure, non-Cartesian forms of substance dualism that might have the resources to confront the Problem of Interaction in its various guises (Hasker 1999; Lowe 2006). But the dominant view today would appear to be that if the mind is a substance at all, it is a physical substance—the brain, for instance. This sort of “substance monism” is in fact a consequence of the more general token identity theory: every concrete mental particular (token) is physical. We will assume token identity in what follows: minds, mental events, and any other mental “objects” are physical (see the mind/brain identity theory).  