Jim Holt, a columnist and contributor to the _New Yorker_, collects jokes, and the shortest among them is two words: "Pretentious? Moi?" It is fitting that he has included it in his book _Stop Me If You've Heard This: A History and Philosophy of Jokes_ (Norton), for his own book is tiny, and despite its brevity, it succeeds in delivering its intended history and philosophy just as well as the two-word joke delivers a smile. It might seem strange that jokes should be a subject for philosophical enquiries, but consider how central they are to the human condition. Sit down at a dinner party, and a good deal of the conversation will be directed at putting together strings of words that will elicit laughter from the hearers. Another reason jokes ought to be considered food for philosophical thought is that philosophers through history have indeed speculated about them, and have come up with answers about why jokes are funny, but none of the answers is complete or completely satisfying. Another reason to study the history and philosophy of jokes is that when one does so, one necessarily gets to read lots of jokes, and Holt's little volume does contain plenty of good ones.
The book is divided into two parts, necessarily "History" and "Philosophy". There were jokebooks of the ancients, since Plautus refers to their existence in his comic plays, but only one has come down to us, the _Philolegos_ ("laughter lover") from the fourth or fifth century C.E. The jokes in it are peopled with stock characters like the miser, the drunk, and the sex-starved woman. "How shall I cut your hair?" a talkative barber asks a customer. "In silence!" comes the retort. Holt writes admiringly of the more contemporary work of joke collector Gershon Legman, who claimed to have invented the slogan "Make Love, Not War" and who obtained books for Alfred Kinsey's collection. The admiration is muted, however: "Reading through Legman's vast compilation of dirty jokes is a punishing experience, like being trapped in the men's room of a Greyhound bus station in the 1950s." Philosophy, of course, seems to begin with the Greeks; Plato said that the proper objects of laughter are vice and folly, both well illustrated in jokes here. Immanuel Kant explained that incongruity was what led to laughter, but the philosopher Henri Bergson said that laughs came from a feeling of superiority; watch a man slip on a banana peel, and you laugh because you, yourself, would never, ever exhibit such gracelessness. Freud famously proposed that a joke allows laughter to release inhibited thoughts and feelings of sex and aggression. That sounds good, but Holt notes that if Freud is right, the ones "who laugh hardest at lewd jokes should be the ones who are the most sexually repressed. This seems to be backwards. No general explanation of why we laugh at jokes seems to work in all cases, and the problem may be that trying to understand the funniness of specific jokes is just not funny. The explanation of a joke is not funny, it never helps us appreciate the joke more (and often less), and it seldom seems like a good explanation.
As with so many philosophical issues these days, perhaps only because of our current fashions of research, humor may simply come down to the neurological. Using an electric probe to try to find the cause of a patient's seizures, doctors stimulated a part of her left frontal lobe, eliciting a laugh. It happened over and over, and it was not just a mere physical reflex. She really did find things funny, whether she was looking at the operating team, or at a picture of a horse they showed her. Put a little current to the "L-spot" of the brain, and everything becomes a joke. There is little risk that neurosurgical procedures are going to impair the activities of joke-tellers, however; telling a joke is a simpler way of getting a laugh than doing brain probes, and anyway, whatever the purpose of jokes is, it probably cannot be accomplished in such an electromechanical way. Like many things, jokes are probably best appreciated for themselves and not for any thinking that they might inspire. Holt's little volume will inspire some thinking, but it also contains more than its share of good (along with some bad) jokes, including one that he has traced back in different forms which people have been laughing at for fifteen centuries. And he even includes a personal favorite of mine, a meta-joke: "A priest, a rabbi and a minister walk into a bar. The bartender says, `What is this, a joke?'"