This Letter begins with Screwtape expressing satisfaction that the young man has now been "friended" by the 'cool people' in his social circle: those "thoroughly reliable...steady...consistent scoffers and wordlings who without any spectacular crimes are progressing quietly and comfortably toward Our Father's (the devil's) house". Apparently, Wormwood has observed and reported back that these hipsters are "'great laughers", and Screwtape takes up this topic as important with his understudy.
The demons are interested in what makes us laugh, apparently, and they have divided our laughter into 4 sources or types: Joy, Fun, Joke Proper, and Flippancy. The first, joy, is a very familiar concept for us as Believers (I wrote a post a while back about joy vs. happiness), and the demons totally get that joy is a God concept. So, pretty much, they know they can never mess with our true joy in the Lord, and they hate that. Screwtape describes joy as a disgusting and "direct insult to the realism, dignity, and austerity of Hell". Now, if that wouldn't make you want to pursue joy, I don't know what would.
The demons are not particularly interested, from a soul-crushing perspective, in human fun, either. As Screwtape laments, fun can promote "charity, courage, contentment, and many other evils" (remember, "evils" to the demons are those things that keep our eyes on God). The only time demons have any potential interest in our fun-having is when it diverts our attention away from God and onto what we are feeling or doing.
Now, Jokes, are starting to get into the devil's territory. Let's be real -- most jokes are based on the inappropriateness of something, usually sex. We laugh at dirty jokes because we are either uncomfortable or because we just like talking about sex. And when we're not laughing and joking about sex, Screwtape says, we're finding humor in "destroying shame" - in other words, making ourselves feel better about our own meanness, cowardice, and cruelty by cracking a joke (as in "practical joke"). As Lewis writes, there's no straighter shot to damnation than when we assume we can do pretty much anything we want "if only it can be treated as a joke".
But, flippancy is the "best of all", according to Screwtape. Flippant people make a joke out of virtue - or, at least, act as if virtue is funny. This clever crowd operates under the assumption that the joke "has already been made, although no one ever really makes it" and approaches every serious subject "in a manner which implies that they have already found a ridiculous side to it". How convenient, I'm thinking. If you can just maintain flippance (is that a word?) about everything, then you can pretty much go through life without any meaningful values, virtues, or convictions. However, as Lewis writes, flippancy is "a thousand miles away from joy; it deadens instead of sharpens the intellect; and it excites no affection between those who practise it" (So true. Mean Girls are even mean to each other).
So, I gotta ask: What makes you (me) laugh? What do I (you) find humor in?
What we find funny says a lot about our spiritual condition. And that's no joke.