 Descartes accepted the common assumption that not only do physical events have mental effects, but mental events have physical effects (for example, thinking about the political situation makes me write a letter). The difficulty for his dualism, it was thought, was to understand how the nonphysical could have effects on the physical. But if zombies are possible — requiring the physical world to be causally closed — there is no work for nonphysical qualia to do. In that case the difficulty is to understand how, in spite of appearances, the nonphysical could fail to have effects on the physical. Still supposing zombies are possible, it then becomes hard to see any alternative to parallelism or epiphenomenalism, with the radical revision of common assumptions about mental causation that those views entail. True, the friends of zombies do not seem compelled to be epiphenomenalists or parallelists about the actual world. They may be interactionists, holding that our world is not physically closed, and that as a matter of actual fact, nonphysical properties do have physical effects. Or they may favor ‘panprotopsychism’, according to which what is metaphysically fundamental is not physical properties, but phenomenal or ‘protophenomenal’ ones (Chalmers 1991, 297—299; 1999, 492) — a view arguably compatible with the causal closure of the physical. But neither of those options is easy. Abandoning causal closure conflicts with empirical evidence; while the idea that phenomenal or quasi-phenomenal properties are fundamental is obscure.