Screwtape divides humor into four classes:

  1. Joy–which he does not understand at all
  2. Fun–less dangerous to him than joy but still not his cup of tea
  3. The Joke Proper–the ability to laugh off shame or guilt
  4. Flippancy-making light of serious things

First of all, the devil wants nothing to do with joy. It is not his invention; he loathes joy and wants no part in it. He detest any real exercise in joy and hates the celebration that accompanies good music. Fun does not annoy him the way joy does but he is not really all that much in to fun although he will use it to suit his purposes on occasions. Sometimes having fun is a diversion from something more important: so, the devil can use fun but he prefers the last two.

It is the Joke Proper and Flippancy that he loves. Humor can be used to deflect the sting of shame and this is where the joke proper comes into play. A person with a skilled sense of humor can deflect shame by making a joke of their sin. It is the best way to evade the shameful side of your sin in the social setting. A man enslaved to lust might make a crude joke of his lust in a particular instance but do so in such a way that it is humorous to his audience. Immediately, they know that he is lustful but the fact that they laughed with him as he joked about his lust has greatly reduced the sting of shame. Nothing seems all that bad as long as we can treat it like a joke.

Flippancy is by far the devil’s favorite form of humor. The flippant make a joke of everything, secular or sacred. Matter of fact, there is nothing sacred to the flippant. They make jokes about hell, lust, adultery, fornication, fidelity, chastity, devotion, and many other such good things. Flippancy becomes like a coat of armor; it is impossible to reach the heart of a flippant man. His insincerity shields every advance of anything serious. When you try to talk to them about sin–they joke. If you talk to them about hell–they joke. They take nothing seriously; everything is a joke. The flippant deny reality. Hell is no joke. All the jokes in the world do not make it any less real.