Paul Boghossian defends a meaning‐based approach to the apriority of the propositions of logic. His model is based on the idea that the logical constants are implicitly defined by some of the axioms and inference rules in which they are involved, thereby offering an alternative to those theories that deny that grasp of meaning can contribute to the explanation of a thinker's entitlement to a particular type of transition or belief.

There is a long tradition in philosophy of using a priori methods to draw conclusions about what is possible and what is necessary, and often in turn to draw conclusions about matters of substantive metaphysics. Arguments like this typically have three steps: first an epistemic claim , from there to a modal claim , and from there to a metaphysical claim.

It is argued that, because of scientific essentialism, two currently popular arguments against the mind-body identity thesis -- the multiple-realizability argument and the Nagel-Jackson knowledge argument -- are unsatisfactory as they stand and that their problems are incurable. It is then argued that a refutation of the identity thesis in its full generality can be achieved by weaving together two traditional Cartesian arguments -- the modal argument and the certainty argument. This argument establishes, not just the falsity of the identity (...) thesis, but also the metaphysical possibility of disembodiment. (shrink)