© LOGOS & EPISTEME, X, 4 (2019): 445-447 WHY MUST JUSTIFICATION GUARANTEE TRUTH? REPLY TO MIZRAHI Howard SANKEY ABSTRACT: This reply provides further grounds to doubt Mizrahi's argument for an infallibilist theory of knowledge. It is pointed out that the fact that knowledge requires both truth and justification does not entail that the level of justification required for knowledge be sufficient to guarantee truth. In addition, an argument presented by Mizrahi appears to equivocate with respect to the interpretation of the phrase "p cannot be false". KEYWORDS: Moti Mizrahi, factivity, epistemic certainty, fallibilism, knowledge I. In "You Can't Handle the Truth: Knowledge = Epistemic Certainty," Moti Mizrahi claims that the factivity of knowledge entails that knowledge is epistemic certainty.1 In "Factivity or Grounds? Comment on Mizrahi," I pointed out that Mizrahi's argument that knowledge is epistemic certainty requires more than the simple assumption that knowledge is factive.2 In addition, Mizrahi must also adopt an assumption about the relationship between grounds (or evidence) and knowledge. In "Factivity and Epistemic Certainty: A Reply to Sankey," Mizrahi agrees with me on the above point.3 He agrees that "strictly speaking" the assumption of factivity tells us nothing about the relationship between grounds and knowledge. However, he thinks that a version of his original claim can still be maintained. He asserts that "the claim that knowledge is factive does say something about a 1 Moti Mizrahi, "You Can't Handle the Truth: Knowledge = Epistemic Certainty", Logos & Episteme X, 2 (2019): 225-227. 2 Howard Sankey, "Factivity or Grounds? Comment on Mizrahi," Logos & Episteme X, 3 (2019): 333-334. 3 Moti Mizrahi, "Factivity and Epistemic Certainty: A Reply to Sankey," Logos & Episteme X, 4 (2019): 443-444. Howard Sankey 446 relation between grounds and knowledge."4 The reason is that in the same way that knowledge requires truth, it "also requires justification."5 Mizrahi writes in more detail as follows: ... if S has no grounds for believing that p, then S cannot be said to know that p. On the other hand, if S knows that p, then p must be not only true but also justified. Therefore, the claim that knowledge is factive does say something about the relation between knowledge and grounds insofar as knowledge requires justification. And justification (i.e. reasons or evidence) is that which makes a proposition epistemically certain.6 In other words, it is because knowledge requires both truth and justification that the level of justification required for knowledge must be sufficiently high to guarantee truth. It is not just that knowledge is factive, but that it is factive and it requires justification. II. Mizrahi assumes that knowledge requires truth. That is what is meant in this context by saying that knowledge is factive. He also assumes that knowledge requires justification. Hence, knowledge requires both truth and justification. Mizrahi takes the fact that knowledge requires both truth and justification to entail that justification must guarantee truth. For this reason, he assumes that the level of justification required for knowledge is certainty. For it is only if justification is epistemic certainty that justification may guarantee truth. I regard the assumption that justification must guarantee truth as problematic. Like Mizrahi, I assume that knowledge requires both truth and justification. Truth and justification are necessary conditions for knowledge. But they are distinct conditions for knowledge: one condition may be met without the other being met. The assumption that knowledge requires truth and justification does not entail that the level of justification of a belief be sufficient to guarantee truth of the belief. Mizrahi assumes that in order for a justified true belief to constitute knowledge the justification of the belief must guarantee the truth of the belief. In other words, justification must guarantee truth. It is entirely possible that an argument might be given for this assumption. But, so far as I can see, no such argument has been supplied by Mizrahi. The simple point that knowledge requires 4 Mizrahi, "Factivity and Epistemic Certainty," 443. 5 Mizrahi, "Factivity and Epistemic Certainty," 443. 6 Mizrahi, "Factivity and Epistemic Certainty," 444. Why Must Justification Guarantee Truth? Reply to Mizrahi 447 both truth and justification does not by itself entail that justification be a guarantor of truth. III. Toward the end of his reply, Mizrahi offers the following argument for his view: (1) If S knows that p, then p cannot be false (2) If p cannot be false, then p is epistemically certain. (3) Therefore, if S knows that p, then p is epistemically certain.7 This argument may at first blush appear to be valid. On closer inspection, it appears to equivocate with respect to the phrase "p cannot be false." In its first occurrence in premise (1), the phrase "p cannot be false" is taken to state a necessary condition for knowledge. But in its second occurrence in premise (2), the very same phrase is taken to either mean or entail that p must be certain. But the fact that, if p is false, S does not know that p, does not entail that p must be certain. Truth is a necessary condition for knowledge. To say that truth is a necessary condition for knowledge is not to say that knowledge requires certainty. It is just to say that if the proposition believed by the subject is false, then justified belief in that proposition does not constitute knowledge. It fails to be knowledge because the proposition in question is false. IV. I do not wish to suggest that no argument may be given for the infallibilist view that the level of justification required for knowledge is epistemic certainty. What I do wish to suggest is that, in his original note and subsequent reply, Mizrahi has not provided such an argument. I have no doubt that one might have an intuition to the effect that justification must guarantee truth. But, without an argument, those of us who do not share that intuition are left without grounds to adopt the infallibilist point of view. 7 Mizrahi, "Factivity and Epistemic Certainty," 444.