I've received a few fascinating emails on the theology of humor from Donald Casadonte, a chemist and secular Carmelite who also studies humor. He's given me permission to post them, and I'll do so in a series of hopefully bite-size (and lightly edited) posts.
As someone who studies humor (yes, there are a few of us), I think this is a very interesting topic because there is very little written about religion and humor. There is a lot written about religious humor (if you see the difference), but very little written on why God created man with the faculty of humor. I know of only one article of any substance by a Catholic writer: Archbishop Sheen, in a book entitled, Science, Psychology, and Religion, if memory serves on the title. He writes that humor in man is a sign that man has a rational soul. I do not know that St. Thomas has any discussion on humor, per se (mirth is not exactly humor, but is related), but I suspect that he might have agreed.
I love the distinctions. Religious humor is not the same topic as religion and humor. Humor is not the same as mirth. And the existence of the International Society for Humor Studies, with its upcoming conference in Copenhagen... well, I think the world is a better place just knowing that the ISHS exists.
There is a book written by the philosopher, John Morreall called, Taking Laughter Seriously, which has a section on God. He asks the questions: if humor involves surprise, and God cannot be surprised, can God find anything funny.
I wrote back a long letter explaining that God could, indeed find things funny, in that Christ was a man in all things but sin, and that includes laughter. It is simply impossible to believe that the Christ who wept would be a Christ who could not laugh. Christ's laughter, however, would have been within the bounds of discretion or discretio, as the Benedictines would say: a proper use.
I realize that there is a difference in ontological objects between Christ in his humanity and Christ in his divinity, but it can be said that God understands laughter at the very least from having lived among us. Christ in his divinity is the author of humor; Christ in his humanity appreciates its expression. This is essentially the argument that St. Thomas makes regarding God as the efficient cause of humor relating to God's simplicity, but we must not forget the humanity of Christ, as well. Christ is both utterly simple and utterly human. He is the only example of such and therefore, holds a unique spot in humor.
Chesterton ended Orthodoxy with the speculation, "There was some one thing that was too great for God to show us when He walked upon our earth; and I have sometimes fancied that it was His mirth." I have sometimes fancied that Chesterton's fancy got the better of him, but now I wonder whether any details of Christ's laughter would be too much for us. I mean, what if He laughed at a joke we didn't laugh at?