In his Contra Academicos, Augustine offers one of the most detailed responses to scepticism to have come down to us from antiquity. In this paper, I examine Augustine’s defence of the existence of infallible knowledge in Contra Academicos 3. I challenge a number of established views (including those of Myles Burnyeat, Gareth Matthews, and Christopher Kirwan) concerning the nature and merit of Augustine’s defence of knowledge and propose a new understanding of Augustine’s response to scepticism (including his semantic response to (...) external world scepticism) and several important elements of Augustine’s thought concerning signification, cognition, and object-directed thought. I argue that once we properly understand Augustine’s views about these issues, his arguments in defence of knowledge are more interesting and more successful than usually thought. (shrink)