by Tony Veale

Stand-up comics often bemoan the fact that "everyone's a f**king comedian!", and its true: every one appreciates humor (to some degree) and most are capable of generating some form of spontaneous humor. But this very ubiquity makes humor harder, rather than easier, to understand formally, since humor assumes many guises and operates with subtle differences in myriad contexts. A whole host of philosophers and other thinkers have proposed theories of humor throughout history, though none are wholly successful, since each tends to emphasise one favored aspect of humor over others. My favorite perspective is offered by Aristotle, who views humor as a form of "educated insolence". Of course, you have to overlook the dry details of Aristotle's schoolmasterish analyses, and his love of dividing every topic into seven types of this and five sub-types of that. When considering a theory of humour, look past the details (they are often extremely sketchy, anyway), and try to distil the essence to see if it does justice to the phenomenon.

What does it mean to say that "humour is educated insolence"? Well, in two key-words, Aristotle says it all. The first, "educated", does not mean that humor can only arise from a formal education, rather that humor is a knowledge-based process. To make fun of the world or its occupants, one needs to exploit knowledge, and the richer this knowledge, the more nuanced and sophisticated the humor can be. To a computationalist, this means that knowledge-representation is a foundational element of a theory of humor. Theorists in Artificial Intelligence have studied this problem for five decades now, to produce a host of representation schemes and reasoning mechanisms for those schemes. Some ambitious projects, like the Cyc project in Austin, aim to use these schemes and mechanisms to represent the totality of common-sense knowledge possessed by a typical human. While I have my doubts about Cyc as a representation for computational humor (I worked on the project for a year) I believe that the "knowledge-bottleneck", as Cyc's guiding svengali Doug Lenat describes it, is a crucial issue in humor research: no knowledge, no humor, and no humor generation.

The second word, "insolence", is just as important, as it describes how one should use all this knowledge to understand and produce humor. One might be tempted here to see insolence as a form of insulting behavior, and thus view humor as an expression of superiority on the part of the comic. This general theory, called the superiority theory of humor, views humor as aggressively directional, so that every joke has a target or a butt. However, insolence is a more general idea, and refers to a subversive attitude not just toward other people (as some humor is overtly aggressive) but toward situations, beliefs and knowledge itself. Personally, I am inclined to see in humor the same kind of subversive behavior we see in scientific Gedanken or thought experiments. In such experiments, a scientist proposes a simple experiment that requires no apparatus, but which can instead be performed in the laboratory of the mind. Galileo and Einstein were both masters of the Gedanken experiment, using them to devastating effect to persuade people of the folly of believing in conventional scientific wisdom. Once this wisdom is shown by the experiment to lead to ridiculous situations, the stage is cleared for a new theory to arise. As such, I see many jokes as having the character of a compressed thought experiment. Try this one on for size:

"If God wanted us to be vegetarians, he wouldn't have made animals out of meat!".

Which ideas are subverted here, Vegetarian, Animal or Meat? The answer appears to be all three, for we seem to be presented with three quite exceptional objects that simultaneously subvert three different categories. First we are directed to imagine an exceptional member of the Animal category, the animal as meat machine, from which all non-utilitarian aspects are divorced; if such an animal were not sentient, there could be no moral basis for vegetarianism. Secondly, we are asked to imagine an exceptional kind of meat, one that possesses all the biological properties of conventional meat yet one that may not derive from an animal source. Thirdly, we are directed to imagine an exceptional kind of Vegetarian, one that would eat meat if did not derive from an animal source. All three subversions together lead to a subversion of the category Vegetarianism, for what moral force would this lifestyle preserve if vegetarians could freely eat meat yet remain a vegetarian? The above joke really is a highly compressed thought experiment, since it attempts to undermine the conventional wisdom that vegetarianism is a morally superior way of life, while justifying a moral laissez faire on the part of the meat-eaters. Some of the most effective uses of subversion aim for a more visceral effect, as in "Eating is over-rated. Remember, food is just sh*t waiting to happen".

When most people hear that computer scientists are trying to model humor processes on a computer, their reactions typically range from the "why bother" (or "don't expect tenure") to "it's clearly impossible". As a topic of computational research, humor seems both wasteful and futile; even it succeeds, do we really need a computer with a sense of humor? Those people that already believe that computers are too smart for them would surely not be pleased to think that their computers are also laughing at them. It doesn't help, of course, that the archetype of intelligent computers in pop-culture is HAL from 2001, who murdered his crew. When I worked at Cyc, my boss looked forward to the day that Cyc would exhibit language capabilities like HAL, but presumably (and I can't be sure) he wasn't looking forward to Cyc murdering me and my co-workers.

More seriously, few computer scientists work on humor as their main topic of research, and for most, like myself, it is an interesting (but relevant) side-line. For one, is not an entirely wise career choice. I've met graduate students at humor conferences (yes, they exist, but they can be very dry indeed) who are there against the advice of their supervisors, who suggest it is better to study these topics after tenure has been secured (this places humor research in the same scientific category as paranormal studies!). Second, and more realistically, there are so many problems to do with general human intelligence and language competence that must be solved first before we can even begin to think about genuinely humorous computers. The state of the art in computer-generated humor is still in the school-yard, intellectually speaking. Computers can do a very good job of generating puns, and even humorous acronyms (such as CIA = Central Incompetence Agency, to pick one at random). To understand and generate truly conceptual humor, where ideas rather than just words are manipulated, requires that we first understand other aspects of creative language use. To my mind, the most important aspect of human language is metaphor. This is the primary focus of my research (though its only slightly more respectable than humor in computer science circles), since metaphor underpins our ability to stretch the conventions of language and describe people and ideas in strikingly novel ways. You don't need to read poetry to encounter the need to process metaphors. Almost all natural language texts are permeated with metaphors, from the Bible to the Wall Street Journal, so there is a real financial imperative to make substantial engineering progress on this topic. Once our computers can understand and produce metaphors, they will possess the educational requirement of Aristotle's theory. Then it will be a matter of using this education for insolent purposes. Choice insults like "Baldrick, your family tree has Dutch Elm disease" are just around the corner.

For those readers interested in knowing more about computational approaches to metaphor, and indirectly, humor, please do visit my group's research web-site at: afflatus.ucd.ie. (btw: "Afflatus" is not a bowel-complaint, but a pretentious term for the "creative urge" foisted upon our server by a departing graduate student). Alternatively, you can contact me directly at tony.veale@UCD.ie.

Tony Veale is a computer scientist at University College Dublin. He's also our guest on today's show on humor.