Humor plays an extraordinary role in everyday life. The traditional Martian observer might marvel at our craving for the incapacitating, nonproductive seizures known as laughter. Many major philosophers have proposed an account of it—an expression of superiority (Plato, Aristotle, Hobbes), the perception of an incongruity (Kant, Schopenhauer), the venting of excess energy (Freud). Each seems to capture some important insight, but not the whole.
Inside Jokes argues that these explanations are typically misdirected. There are no intrinsic properties of jokes or funny situations because humor is a “secondary quality.” A quality is primary if, like the shape or weight of a physical body, it is independent of an observer; it is secondary if, like taste or smell, it is an effect produced in observers, and therefore a product of each observer’s perceptual systems. The mechanisms by which we perceive humor are cognitive. What’s needed is a description of how humor works, of the mental processing involved in finding something funny. A full account will go beyond description to explain not just what humor is but why it exists at all.
The theory here, in rough outline: We cannot function without constantly jumping to conclusions, constructing “mental spaces” through which we interpret the present and anticipate the future. We construct these from current perceptions, free associations, memories, inferences, and so on, and they will inevitably be inconsistent. We are forced to recognize and resolve contradictions that are overt. Thinking Fred is away, I plan to use his office for a meeting, and arrive at work to find him at his desk. But it takes effort to ferret out lurking inconsistencies, whose consequences (if any) may be remote. We have evolved a mechanism that rewards us for detecting them—and that is the basis for “primitive humor.” Art and culture have subsequently exploited this capacity for the sake of conviviality, sexual competition, and stand-up comedy.
Humor happens when I discover that a belief that has entered a mental space “covertly,” and that I have committed to, conflicts with other beliefs in that space. (Proviso: The discovery must not cause strong negative emotions, which may overcome humor’s pleasures.) Consider a scenario proposed by Charlie Chaplin. The camera cuts back and forth between a fat lady taking a walk and a banana peel in her path, zooms in as she approaches it, then shows her stepping blithely over it . . . into an open manhole. My attempt at analysis: The setup focuses our attention on the banana peel, brings to the front of our minds expectations about what happens in comedies to someone who steps on a banana peel, and seduces us into the covert assumption that all will be well if he doesn’t. The punch line exposes that mistake. If someone in the next seat says, “He thinks he only needs to walk around it,” that spoils the joke and the theory explains why: The belief that all will be well has been made overt, so contradicting it doesn’t trigger
The reward I get for detecting my own mistake is “first-person” humor. The theory of Inside Jokes holds that I can also get a laugh from “third-person” humor—recognizing an “overcommitted belief” in someone else, who may be fictional. In the scene just described, that hasn’t much kick; the man is a cipher who excites little interest. But make him Inspector Clouseau, defined by the rigor with which he ignores the gap between his beliefs and reality, and the scene could be funny even if a director eliminated the first‑person humor by tipping us off about the manhole. (One consequence of this distinction is that jokes exploiting third‑person humor should be the ones that we can laugh at repeatedly.)
The authors apply their theory to a wide range of examples—jokes, word play, nonverbal humor, found humor, unfunny situations, tickling (a notoriously awkward example), malicious humor, spoiled jokes—including cases difficult for other theories to handle. They evaluate it against a checklist of questions that any good theory of humor should satisfy. For example, why do we laugh only at humans or at anthropomorphized objects? (Answer: We can laugh only at things capable of faulty reasoning, therefore only at things capable of reason.) It is an impressive performance.