The epistemology of religious belief, a central topic among medieval philosophers, shows no signs of disappearing from the public’s consciousness or the philosophers’ agenda. The reason why is not hard to find. Large-scale advances in science, rightly heralded as triumphs of reason, have been alleged to have implications for the rationality of religious faith: one need only think of the development of evolutionary biology in the past 150 years and of physical cosmology in the past fifty. Of course, the medieval philosophers knew nothing of evolutionary biology. And although they speculated about one big issue in physical cosmology – whether the world was created or has existed forever – their speculations were shaped not by experimental evidence but by Scripture and Aristotelian science. Nevertheless, it does not follow that medieval debates about faith and reason have been superseded. It may well be that contemporary debates on the relation between faith and reason would benefit from a fresh examination of medieval discussions.
A few preliminary, terminological remarks are in order, first about reason, then about faith. First, in theological contexts, reason is sometimes contrasted with divine revelation, especially when revelation is restricted in its application to doctrines alleged to be beyond the powers of human reason. There is a more expansive conception of reason according to which reason can discover on its own some items of revelation, but this chapter will exclude discussion of that possibility. Second, reason is sometimes distinguished from understanding. Reason, it is said, is discursive while understanding is intuitive.