ON THE TWO KINDS OF ARGUMENT BY WHICH EVERY DISPUTATION IS CONDUCTED
Before I enumerate the theological loci, as the first part of this disputation promises to do, we must establish that every argument is drawn either from reason or from authority. For by these two means we give assent to whatever matter comes into controversy. While in all the other disciplines reason holds first place and authority the last, theology alone is such that in disputation one must seek not so much the force of reason as that of authority. Indeed, it has claimed the argument from authority as peculiarly its own, so that it either receives reasons as guests and strangers, or even enlists them in its service as things fetched from far away. For it rests chiefly on faith, which, unless it proceeds from authority, cannot merely fail to be faith; it cannot even be understood. For faith, as the Apostle teaches, is the evidence of things not seen, as though you wished to establish certain things by a certain reason: with reason, you would surely be out of your mind. Therefore, among the faithful as among theologians, authority holds the leading place. Reason follows afterward, like a handmaid.
The Apostle seems to signify this when he says that a teacher in the Church must hold fast to the faithful word that accords with the teaching, so that he may be able to exhort with sound doctrine and refute those who contradict it. Whoever would be a teacher in the Christian school must first, necessarily, grasp the word of faith; but unless he soon applies the reasoning of doctrine, he may indeed be faithful, but he will not be able to be a teacher of the faithful. For even people who are highly experienced cannot, as St. Thomas rightly infers from Aristotle, dispute with their adversaries unless the reasoning of an art is added to experience. Both, then, are necessary for a theologian—authority and reason—yet in such a way that authority takes the first parts in theology, while reason has the last. Thus what was the foundation of the first part has been splendidly laid. For the loci from which arguments are drawn have indeed been handed down as twofold: some derive from authority, others from reason; yet nearly all theological arguments flow from that former source. The index that follows will show this, as well as the number and order of the loci.