 Although contraposition is valid for the material conditional \((A \supset B\) iff \(\mathord{\sim} B \supset \mathord{\sim}A)\), Sosa suggests that it is invalid for counterfactuals, which is why sensitivity and safety are not equivalent. An example of a safe belief that is not sensitive, according to Sosa, is the belief that a distant skeptical scenario does not obtain. If we stipulate that George, discussed above, has never been at risk of being the victim of a Cartesian demon—because, say, Cartesian demons do not exist in George’s world—then George’s belief that he is not such a victim is a safe one, even though we saw in the previous section that it could not be sensitive. Notice that although we stipulated that George is not at risk of deceit by Cartesian demons, we did not stipulate that George himself had any particular access to this fact. Unless he does, safety, like sensitivity, will be an externalist condition on knowledge in the “access” sense. It is also externalist in the “state” sense, since the truth of the relevant counterfactuals will depend on features outside the subject.