Abstract
Drawing upon Saul Kripke’s discussion of rules, James F. Ross deduces the immateriality of thinking from the metaphysical determinacy of thinking and the metaphysical indeterminacy of any physical process. It has been objected that Ross does not establish the metaphysical indeterminacy of what function a physical process realizes, that Ross does not show the incoherence of a highly deflationary view of our talk about thinking, and that Ross opens up an unbridgeable gulf between sui generis thinking and behavior. Edward Feser has recently defended Ross’s argument from these objections. The present paper explains why Ross’s argument remains vulnerable to all three objections