Bad arguments have never been in short supply. The scholarly interest they have elicited in recent years, on the other hand, is quite exceptional. Fallacy studies have become a well established and flourishing field of argumentation theory. Without notable exception, the ever-growing literature on argumentative failures suffer from a conspicuous lack of interest in Mediaeval fallacy theory – arguably the most creative stage in the whole history of argumentation theories. The standard story is that after Aristotle got off to a tentative start, the study of fallacies laid dormant until people at Port Royal and John Locke revived it in spectacular fashion.