Is Understanding a Source of Epistemic Justification?

Célia Teixeira (Universidade Federal do Rio de Janeiro)

12 June 2026, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: The claim that understanding is a source of epistemic justification has been closely tied to the debate about the a priori. How do we know a priori truths such as that bachelors are unmarried, or that knowledge entails truth? According to a widely held view, we do so by understanding alone—and understanding is the source of the a priori. I examine this view. I begin by showing that it is ambiguous between semantic understanding and rational understanding. Focusing on the former, I distinguish a weak role for semantic understanding—on which it justifies beliefs about meaning—from a strong role—on which it justifies beliefs in non-semantic a priori truths. The weak role is uncontentious and unmysterious; the strong role is neither. I argue that semantic understanding might be the source of justification by which we know semantic truths, but not non-semantic a priori truths. For that, we need rational understanding. I then conclude by sketching an account of rational understanding as the source of most of our a priori knowledge.