Abstract

Peter van Inwagen's influential Direct Argument (DA) for the incompatibility of moral responsibility and causal determinism makes use of an inference rule he calls "Rule B." Michael McKenna has argued that van Inwagen's defense of this rule is dialectically inappropriate because it is based entirely on alleged “confirming” cases that are not of the right kind to justify the use of Rule B in DA. Here I argue that McKenna’s objection is on the right track but more must be said if we are to see why. To fill in the gaps I consider a recent attempt by Ira M. Schnall and David Widerker to defend DA against McKenna’s objection. I argue that neither prong of their attack is successful against a variation on McKenna’s basic argument. In the course of responding to Schnall and Widerker’s objections to McKenna, I identify what is, as I argue, the real reason DA fails in its purpose to shift the burden of proof.