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 r