Oh dear, maybe I didn't make myself clear enough. For the record, Caledonian, I agree with you: dualism is false; materialism is true.

My previous comment merely reflects on that while I believe dualism is actually false, it's not obviously nonsense to posit a mental substance that simply doesn't reduce to anything else, in the way that it's obviously nonsense to posit that the law of noncontradiction is false. Substance dualism isn't incoherent, as far as I can tell; it is "merely" wrong.