What is truth? This is a question that we seldom formulate in these terms, but that we often ask, when we ask ourselves if we really see what we see. Do we really see what we see? To verify, we try to touch. Truth needs a touchstone; it is itself a touchstone. We sense that we have hold of the truth when we can touch what we see. We are in error when we cannot touch what we see--or, rather, that is, what we think we see. A child tries to catch his shadow; the adult has learned to distinguish between what he thinks he sees and what he can grasp. Reason, one might say, is what allows us to link sight to touch. This is often very difficult for us, unlike the cat, which, perceiving the mouse, does not hesitate over what he has to do. One glance and whoosh! Our movements are much less graceful than the cat's; we are a wandering and limping species because it is hard for us to link sight and touch. It is hard, and so we need reason, and reason is work. Why do we make mistakes, why are we capable of error? Because our eye is much bigger than the cat's, bigger even than the lion's, because our eye is huge; it is the eye of the mind. We can see all that is, all that can be, because our intelligence is open to being as such. We can even see what does not exist, since we can imagine it--thus the disproportion between the unlimited scope of what we conceive and the narrowness of what we can touch and verify. And reason ceaselessly runs from one to the other, from what we conceive to what we can verify.
I shall not attempt to define faith, since I am not a theologian and thus have no authority in this area. I shall only observe that the notion of faith in the strong sense that interests us this evening appeared with Christianity and has remained proper to Christianity. With the Incarnation, truth offered itself to be seen and even touched. The very principle of being offered itself to Thomas's observation. Then it withdrew. "Have you believed because you have seen me? Blessed are those who have not seen and yet shall believe" [John 20.29, RSV]-- those who have faith. Faith attains its object without seeing or touching it. Instead of going ceaselessly back and forth, instead of working, it suspends human effort and waits for everything, hopes for everything, expects everything from God.
Reason is more essential to our being than is faith. Reason makes us human. We are human beings only by this faculty of erring and recovering ourselves. To despise reason is to despise one's own being. The greatness of Europe, what makes her unique among the great civilizations, is that she has never relented in the work of reason, she has never tired and never ceased to make reason the touchstone. Europeans have never ceased to bring even Europe's own faith, the Christian faith, before the tribunal of reason, even during the eras that we designate as "eras of faith."
Christian faith, for its part, accepts being called to appear before the tribunal of reason. It is distinctive of the Christian God to leave man to his own counsel, and to put the fulfillment of the plan of salvation as it were at the mercy of human freedom. This is why Christianity is not a law, but a faith. This is why the Bible is not a teaching dictated by heaven like the Koran. It is a chronicle, full of detours, of an often-broken and ever-renewed covenant between divine goodness and human freedom.
Reason's questions do not leave faith without reply. Faith says to reason that one who ceaselessly verifies will never find the truth that is the end of its seeking, in both senses of the term. Would not reason's activity be in vain if there were not a point where man's truth was gathered, a point towards which faith directs us, and hope and faith carry us? However necessary, and even noble, may be the work of reason, the moment comes when one must consent to allow the truth to come towards us.
During the last four centuries we have built a …