"Can you not see," I said, "that fairy tales in their essence are quite solid and straightforward; but that this everlasting fiction about modern life is in its nature essentially incredible? Folk-lore means that the soul is sane, but that the universe is wild and full of marvels. Realism means that the world is dull and full of routine, but that the soul is sick and screaming. The problem of the fairy tale is — what will a healthy man do with a fantastic world? The problem of the modern novel is — what will a madman do with a dull world? In the fairy tales the cosmos goes mad; but the hero does not go mad. In the modern novels the hero is mad before the book begins, and suffers from the harsh steadiness and cruel sanity of the cosmos."

"People like frequent laughter," answered Father Brown, "but I don't think they like a permanent smile. Cheerfulness without humour is a very trying thing."

Mysticism keeps men sane. As long as you have mystery you have health; when you destroy mystery you create morbidity. The ordinary man has always been sane because the ordinary man has always been a mystic. He has permitted the twilight. He has always had one foot in earth and the other in fairyland. He has always left himself free to doubt his gods; but (unlike the agnostic of to-day) free also to believe in them. He has always cared more for truth than for consistency. If he saw two truths that seemed to contradict each other, he would take the two truths and contradiction along with them. His spiritual sight is stereoscopic, like his physical sight: he sees two different pictures at once and yet sees all the better for that. Thus, he has always believed that there was such a thing as fate, but such a thing as free will also. Thus, he believes that children were indeed the kingdom of heaven, but nevertheless ought to be obedient to the kingdom of earth. He admired youth because it was young and age because it was not. It is exactly this balance of apparent contradictions that has been the whole buoyancy of the healthy man. The whole secret of mysticism is this: that man can understand everything by the help of what he does not understand. The morbid logician seeks to make everything lucid, and succeeds in making everything mysterious. The mystic allows one thing to be mysterious, and everything else becomes lucid.