Any philosopher who defends Free Will should have an answer to the epistemological question: “how do we know that we have such a capacity?” A traditional answer to this question is that we have some form of introspective access to our own Free Will. In recent times though, many philosophers have considered any such introspectionist theory as so obviously wrong that it hardly needs discussion, especially when Free Will is understood in libertarian terms. One of the rare objections to appear as an explicit argument was proposed by van Inwagen in his Essay on Free Will. In this paper, I address van Inwagen’s anti-introspection argument; I argue that it is both inconsistent with his overall treatment of the Existence Question (namely, with his defence of the existence of Free Will from reflections about morality), and inconclusive in itself (at least for anyone not ready to endorse general scepticism about perception). In passing, I give a clarification of the notion of Introspection, in the case of Freedom, that also sets a more favourable stage for the evaluation of further objections.