How should the state justify its coercive rules? Public reason liberalism endorses a public justification requirement: Justifications offered for authoritative regulations must be acceptable to all members of the relevant public. However, as a criterion of legitimacy, the public justification requirement is epistemically unreliable: It prioritizes neither the exclusion of false beliefs nor the inclusion of true beliefs in justifications of political rules. This article presents an epistemic alternative to the public justification requirement. Employing epistemological theories of argumentation, we demonstrate (...) how this approach enables assessing the epistemic quality of justifications of political rules, even when the truth is difficult to establish. (shrink)