Free will sceptics deny the existence of free will, that is the command or control necessary for moral responsibility. Epicureans allege that this denial is somehow self-defeating. To interpret the Epicurean allegation charitably, we must first realise that it is propositional attitudes like beliefs and not propositions themselves which can be self-defeating. So, believing in free will scepticism might be self- defeating. The charge becomes more plausible because, as Epicurus insightfully recognised,there is a strong connection between conduct and belief—and so between thecontent of free will scepticism (since it is about conduct) and the attitude of believing it. Second, we must realise that an attitude can be self- defeating relative to certain grounds. This means that it might be self-defeating to be a free will sceptic on certain grounds, such as the putative fact that we lack leeway or sourcehood. This charge is much more interesting because of the epistemic importance of leeway and sourcehood. Ultimately, the Epicurean charge of self-defeat fails. Yet, it delivers important lessons to the sceptic. The most important of them is that free will sceptics should either accept the existence of leeway or reject the principle that ‘“ought” implies “can”’.