In a good deal of philosophy of mind over the last 50 years or so, physicalism seems to have been taken as a kind of absolute presupposition. A good example would be Daniel Dennett, who says “before I could trust any of my intuitions about the mind, I had to figure out how the brain could possibly do the mind’s work.” This leads him to treat the brain as a “syntactic engine” that mimics the competence of semantic engines (though where Dennett thinks semantic engines can be found to mimic is, to say the least, very unclear). This strikes me as dogmatic, and leads me to think that, for the most part, materialist philosophers have not so much solved the problems posed by anti-materialist argument such as the argument from reason, but rather have presupposed that there has to be a materialistic solution to such problems. But what if these assumptions are questioned? If they are questioned, then the problems posed by arguments of the kind I have been presenting seem to me to expose a deep incoherence in philosophical naturalism.