“How Do You Know?” and Challenges to Assertion

Abstract

In addition to the Lottery Paradox and Moore’s Paradox, the third central leg in the argument for the Knowledge Norm involves the wide propriety of challenges to assertions, particularly “How do you know?”1 Typically, KN advocates have argued that “How do you know?” directly challenges whether a speaker knows what she asserts. And, moreover, the wide propriety of challenging a speaker’s assertion with “How do you know?” clearly indicates that one ought to assert only if one knows. So, if knowledge is not the norm of assertion, why would this be such a widely appropriate challenge?