8. Fun is closely related to joy, which also of no use to Screwtape. "A sort of emotional froth aspiring from the play instinct"
9. They can easily be used to steer the patient to the wrong direction. With the the Joke Proper, Screwtape says "which turns on sudden perception of incongruity, is a much more promising field". Explains that the patient's perception on humor can be inappropriate. Flippancy allows Screwtape to make the patient have the inability to take important things seriously.
10. Screwtape uses bawdy humor because the joke can incite the patient to lust and not only to humor.
11. The dangerous aspects of humor are