Is Christianity based on a blind faith? How can you believe something if it cannot be absolutely proven? These are some of the questions that have recently come up in our bible study. The following quote (slightly abridged and with a few added emphases) from C.S. Lewis’ Mere Christianity helps to clarify the meaning of Christian faith.
In one sense Faith means simply Belief—accepting or regarding as true the doctrines of Christianity. That is fairly simple. But what does puzzle people—at least it used to puzzle me—is the fact that Christians regard faith in this sense as a virtue, I used to ask how on earth it can be a virtue—what is there moral or immoral about believing or not believing a set of statements? Obviously, I used to say, a sane man accepts or rejects any statement, not because he wants or does not want to, but because the evidence seems to him good or bad.
Well, I think I still take that view. But what I did not see then— and a good many people do not see still—was this. I was assuming that if the human mind once accepts a thing as true it will automatically go on regarding it as true, until some real reason for reconsidering it turns up. In fact, I was assuming that the human mind is completely ruled by reason. But that is not so.
For example, my reason is perfectly convinced by good evidence that anaesthetics do not smother me and that properly trained surgeons do not start operating until I am unconscious. But that does not alter the fact that when they have me down on the table and clap their horrible mask over my face, a mere childish panic begins inside me. In other words, I lose my faith in anaesthetics. It is not reason that is taking away my faith: on the contrary, my faith is based on reason. It is my imagination and emotions. The battle is between faith and reason on one side and emotion and imagination on the other.
When you think of it you will see lots of instances of this. A man knows, on perfectly good evidence, that a pretty girl of his acquaintance is a liar and cannot keep a secret and ought not to be trusted; but when he finds himself with her his mind loses its faith in that bit of knowledge and he starts thinking, “Perhaps she’ll be different this time,” and once more makes a fool of himself and tells her something he ought not to have told her. His senses and emotions have destroyed his faith in what he really knows to be true.
Or take a boy learning to swim. His reason knows perfectly well that an unsupported human body will not necessarily sink in water: he has seen dozens of people float and swim. But the whole question is whether he will be able to go on believing this when the instructor takes away his hand and leaves him unsupported in the water—or whether he will suddenly cease to believe it and get in a fright and go down.
Now just the same thing happens about Christianity. I am not asking anyone to accept Christianity if his best reasoning tells him that the weight of the evidence is against it. That is not the point at which Faith comes in. Faith, in the sense in which I am here using the word, is the art of holding on to things your reason has once accepted, in spite of your changing moods.