Abstract
This paper presents and defends a novel meta‐epistemological thesis, epistemic isomorphism, according to which our relations to others and to ourselves have the same pattern of relevance to our rationality. This means that correct epistemological theorizing will give formal parity to interpersonal and intrapersonal epistemic norms, such that what holds interpersonally also holds, mutatis mutandis, intrapersonally. In addition to arguing for epistemic isomorphism, the paper presents some epistemological case studies in which it is shown that the methodological and argumentative strategies used by epistemologists in these case studies give expression to the idea of epistemic isomorphism as well as the argument presented here for its truth. Finally, the paper considers a possible counterexample to epistemic isomorphism based on an agent‐centered theory of justification, but it shows how to reconcile this theory with epistemic isomorphism.