No virtues, no prudence : Practical judgement in Thomas Aquinas, John Duns Scotus and Peter Aureol

In Nichomachean Ethics Book VI, Aristotle poses two apparently incompatible theses: One cannot have prudentia without having moral virtues, though one cannot have moral virtues without prudence. Mediaeval thinkers undertake the task of solving this knotted puzzle, interpreting and modifying the Philosopher's ethical theory in logically sophisticated fashion. This article traces three mediaeval theologians' tracks on this count: Thomas Aquinas, John Duns Scotus, and rather less famous Franciscan friar, Peter Aureol. Thomas and Peter pay attention to the prescriptive force normative proposition has. When one concludes a moral judgment after careful deliberation, this judgement has motivating power in itself, actually moving its owner's will to act. Two Theologians agree with ascribing the source of this power to fundamental direction of the will inclined by acquired moral virtues. In this sense, the virtues precede moral deliberation. Duns Scotus, however, takes Aristotle's word in much strictly logical sense and rejects logical contradiction. He chooses to caste out one horn of dilemma and simply dismiss the impossibility of possessing prudence without moarally virtuous habits. The reason why John can take this solution is that he cuts off motivating force from moral judgement, of which Thomas and Peter approve. For Duns Scotus, moral deliberation and final judgement is a judgement only.