 The Cartesian skeptic can nevertheless raise an uncomfortable question at this point: what is this alleged evidence in favor of the proposition that we are not in a skeptical scenario? One tempting answer is that the evidence in question consists precisely of those external world propositions which are the target of the Cartesian argument. I know that I have hands, and, according to this view, that very proposition is my evidence for the proposition that I am not a handless brain in a vat. But recall our discussion of Dretske’s mule case. There we pointed out that Dretske is, in effect, assimilating Closure and Transmission principles—i.e., assuming that the only way in which Closure principles can hold is if some evidence e is evidence both for p and any q entailed by p. We noted then that there is at least another possibility: it might be that we must be antecedently justified in believing q in order to be justified in believing some p which entails it. And indeed, it seems plausible that this is the direction of the evidential relation between external world propositions and the negation of skeptical hypotheses: we cannot be justified in believing external world propositions unless we have antecedent justification for believing the negation of skeptical hypotheses (but cf. Pryor 2000).