According to the transparency approach, achievement of self-knowledge is a two-stage process: first, the subject arrives at the judgment ‘p’; second, the subject proceeds to the judgment ‘I believe that p.’ The puzzle of transparency is to understand why the transition from the first to the second judgment is rationally permissible. After revisiting the debate between Byrne and Boyle on this matter, I present a novel solution according to which the transition is rationally permissible in virtue of a justifying argument (...) that begins from a premise referring to the mental utterance that is emitted in the course of judging ‘p.’. (shrink)