This is an analogy you must understand if you want to understand what living tradition in the Middle Ages means. But in contrast to my example, the tradition was composed of many elements. It happened that these elements didn’t all say the same thing, if you inquired into them. In many cases you had to make decisions. The Middle Ages experienced that first of all in the realm of practical decisions, namely of canon law. The canon law is the basis anyhow of medieval life; the dogma is one of the canon laws – this gives it its legal authority within the Church. In this sense, practical needs produced people who had to harmonize the different authorities on the meaning of the canon laws, as they appear in the many collections of c anon law. Here we have first the harmonizing method, the, method of harmonizing the authorities. One called this the method of yes and no, the dialectical method, which intends to harmonize.
Now we know what reason means in the Middle Ages: it is the tool for this purpose. Reason combines and harmonizes the sentences of the Fathers and the sentences of the Councils and their decisions – first practically and then also in the theoretical realm of theological statements. Therefore the function of reason was to collect, to harmonize, and to comment on the given sentences of the Fathers. The man who did this more successfully was Peter the Lombard , whose sententiae , the sentences of the Fathers, was the handbook of all medieval Scholasticism; everyone commented on it when writing one’s own system.
But another step was taken, namely, this tradition which is now harmonized in the “sentences” of Peter the Lombard, or some others, must be understood; they need commentary; they must be interpreted. The next function of reason was to interpret the meaning of the given tradition expressed in the sentences. This means that the contents of faith had to be interpreted, but faith is presupposed. Out of this situation came the slogan: credo ut intelligam, I believe in order to know. But this simply means: the substance is given; I am living, participating, in it; it is not that I exert a will-to-believe – this is nonsense for the Middle Ages. The creed is given, like nature which is given. Natural science does not create nature; no natural scientist would tell you this. But he calculates the structures and the movements of the given nature. Similarly, reason has the function of interpreting the given tradition – it doesn’t create the tradition. If you keep strictly to these analogies, then you can understand the Middle Ages much better.
This was carried through in the next step, less speculatively, very cautiously, by that group of thinkers which took Aristotle into their theology, and formulate – especially Thomas Aquinas – the relation in such a way that they said: Reason is adequate to interpret authority; reason at no point is against authority, but you are able to interpret that which is given in the living tradition in rational terms, and you don’t need to hurt or destroy reason in order to interpret the meaning of the living tradition. This is the Thomistic position even today.