The motivation of Greek skepticism / The stoicism of the new academy / Stoics and skeptics on clear and distinct impressions / The Ten tropes of Aenesidemus / Can the skeptic live his skepticism? / Ancient skepticism and causation / Augustine against the skeptics / The rediscovery of ancient skepticism in modern times / Lorenzo Valla: academic skepticism and the new humanist dialectic / Skepticism and fideism / Gassendi and skepticism / Descartes's use of skepticism / Locke and pyrrhonism: the doctrine of primary and secondary qualities / Berkeley and pyrrhonism / The tendency of Hume's skepticism / Kant and skepticism