 The crucial thing to note about this proposed counterexample is that it works only if the Closure Principle entails that the very same source of evidence that justifies S in believing that the animals are zebras must justify S in believing that they are not cleverly disguised mules. Since the evidence for the former has been “effectively neutralized”, it is not available for the latter. Now, in response one could claim that once the question of whether the animals are disguised mules has been raised, the evidence is “effectively neutralized” for both the former and the latter, and S is no longer justified in believing that the animals are zebras. Thus, it could be held that this example could actually be used to support CP. Nevertheless, let us grant that the evidence for the claim that the animals are zebras cannot be used to show that they are not cleverly disguised mules. Still, it could be argued that this would not force giving up CP.