C.S. Lewis on Faith in a Certain SenseMere Christianity (New York: Simon and Schuster, 1996; orig. 1943), p.125
Now 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. For moods will change, whatever view your reason takes. I know that by experience. Now that I am a Christian I do have moods in which the whole thing looks very improbable: but when I was an atheist I had moods in which Christianity looked terribly probable.