I Confess: The Power of the Confession looks at the history of confessions, which links the legal world of Cicero to our own. In Episode two, Professor John Arnold of Birkbeck College, University of London, takes us into the mental world of the inquisitions. In the Middle Ages, the Western Church was looking for new ways of getting at truth through confession. This was a knotty problem requiring great subtlety. 'Deep is the heart of man, and inscrutable', wrote the Dominican, Bernard Gui. 'The wise inquisitor should be careful to set his course by the replies of the witnesses, the sworn statements of accusers, the counsel of men taught by experience, the shrewdness of his own natural intelligence, and the following lists of questions' (which he went on to supply). And yet, despite all this careful pondering, torture was resorted to again, this time, in the quest to detect and uproot heresy.