 According to a second conception, a subject’s belief is certain just in case it could not have been mistaken—i.e., false (see, e.g., Lewis 1929). Alternatively, the subject’s belief is certain when it is guaranteed to be true. This is what Roderick Firth calls the “truth-evaluating” sense of certainty (1967, pp. 7–8). As with knowing that p, being certain that p entails that it is true that p. Certainty is, however, significantly stronger than lesser forms of knowledge (contra Mizrahi 2019, who conflates knowledge with certainty on the grounds that knowledge is factive). In cases where the subject knows without being certain that p, it is actually true that p, though it could have been false. In that case, of course, the subject would no longer know that p. But, where the subject is certain that p, it does not merely turn out to be true that p—in some sense it could not have been otherwise.