The incongruity theory states that humor is perceived at the moment of realization of incongruity between a concept involved in a certain situation and the real objects thought to be in some relation to the concept.
Since the main point of the theory is not the incongruity per se, but its realization and resolution (i.e., putting the objects in question into the real relation), it is often called the incongruity-resolution theory.
Francis Hutcheson expressed in Thoughts on Laughter (1725) what became a key concept in the evolving theory of the comic: laughter as a response to the perception of incongruity. Arthur Schopenhauer wrote that the perceived incongruity is between a concept and the real object it represents. Hegel shared almost exactly the same view, but saw the concept as an “appearance” and believed that laughter then totally negates that appearance.
The first formulation of the incongruity theory is attributed to the Scottish poet Beattie.
The most famous version of the incongruity theory, however, is that of Kant, who claimed that the comic is “the sudden transformation of a strained expectation into nothing.” Henri Bergson attempted to perfect incongruity by reducing it to the “living” and “mechanical”.
An incongruity like Bergson’s, in things juxtaposed simultaneously, is still in vogue. This is often debated against theories of the shifts in perspectives in humor; hence, the debate in the series Humor Research between John Morreall and Robert Latta. Morreall presented mostly simultaneous juxtapositions, with Latta focusing on a “cognitive shift” created by the sudden solution to some kind of problem.
Humor frequently contains an unexpected, often sudden, shift in perspective, which gets assimilated by the Incongruity Theory. This view has been defended by Latta (1998) and by Brian Boyd (2004). Boyd views the shift as from seriousness to play. Nearly anything can be the object of this perspective twist; it is, however, in the areas of human creativity (science and art being the varieties) that the shift results from “structure mapping” (termed “bisociation” by Koestler) to create novel meanings. Arthur Koestler argues that humor results when two different frames of reference are set up and a collision is engineered between them.