 According to a third conception of certainty, a subject’s belief that p is certain when it is inimitable--i.e., justified in the highest degree (see, e.g., Stanley 2008). This is what Firth calls the “warrant-evaluating” sense of certainty (1967, pp. 8–12). Thus, Bertrand Russell says that “A proposition is certain when it has the highest degree of credibility, either intrinsically or as a result of argument” (1948, p. 396). There are various ways to understand what it means for a belief to be credible or justified in the highest degree. It could mean simply that the belief in question is justified as highly as any belief the subject happens to hold. But, in cases where the subject does not have any beliefs that are highly justified, this will imply that even a belief with relatively low justification is epistemically certain. Perhaps we could say instead that a belief is justified to the highest degree when it is justified as highly as any belief that anyone happens to hold. But this, too, leaves open the possibility that a belief with relatively low justification is epistemically certain: if all the subjects in existence are in a condition of universal ignorance, all of their beliefs—including the best of them—will have only a low level of justification. Perhaps, then, we should say that a belief is justified in the highest degree when it has the highest level of justification possible. But even this account is unsatisfactory. Suppose that global skepticism is necessarily true: it is a necessary truth that no subject is capable of having much justification for any of her beliefs; although it may seem to us as though a significant degree of justification is possible, this in fact is incorrect. It would then be intuitively correct to say that every belief falls far short of certainty, though this would not be permitted by the account of certainty under consideration. We may of course doubt that skepticism of this strong variety is correct; nevertheless, it should not be simply ruled out as a matter of definition.