Van Inwagen's Consequence Argument

Abstract

In van Inwagen's view, as well as my own, the Consequence Argument is the strongest argument for incompatibilism, and, as he formulates the argument, rule beta is its weakest link.2 For this reason, it is of the utmost importance, in the debate over compatibilism, to determine whether rule beta is valid. In the following, I show, first, that given van Inwagen's definition of 'Np', rule beta is invalid. Its invalidity can be demonstrated by use of a counterexample that does not presuppose either determinism or compatibilism. Second, however, I identify an alternative definition of 'Np' that would suit van Inwagen's purposes, and show that under this alternative definition, rule beta is valid. The rest of van Inwagen's argument remains highly plausible when this alternative definition is used.