Humour or humor (see spelling differences) is the tendency of particular cognitive experiences to provoke laughter and provide amusement. People of all ages and cultures respond to humour. The majority of people are able to be amused, to laugh or smile at something funny and thus they are considered to have a "sense of humour". The question of whether or not something is humorous is a matter of personal taste.
A sense of humour is the ability to experience humour, although the extent to which an individual will find something humorous depends on a host of variables, including geographical location, culture, maturity, level of education, intelligence and context. For example, young children may favour slapstick, such as Punch and Judy puppet shows or cartoons such as Tom and Jerry. Satire may rely more on understanding the target of the humour and thus tends to appeal to more mature audiences. Nonsatirical humour can be specifically termed "recreational drollery".
Arthur Schopenhauer lamented the misuse of the term "humour" (a German loanword from English) to mean any type of comedy. However, both "humour" and "comic" are often used when theorizing about the subject. The connotation of "humour" is more that of response, while "comic" refers more to stimulus. "Humour" also originally had a connotation of a combined ridiculousness and wit in one individual, the paradigm case being Shakespeare's Sir John Falstaff. The French were slow to adopt the term "humour" and in French, "humeur" and "humour" are still two different words, the former still referring only to the archaic concept of humours.
In ancient Sanskrit drama, Bharata Muni's Natya Shastra defined humour (hāsyam) as one of the nine nava rasas, or principle rasas (emotional responses), which can be inspired in the audience by bhavas, the imitations of emotions that the actors perform. Each rasa was associated with a specific bhavas portrayed on stage. In the case of humour, it was associated with mirth (hasya).
The Incongruity Theory originated mostly with Kant, who claimed that the comic is an expectation that comes to nothing. Henri Bergson attempted to perfect incongruity by reducing it to the "living" and "mechanical".
Humour 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 humour results when two different frames of reference are set up and a collision is engineered between them.
Some claim that humour cannot or should not be explained. Author E.B. White once said, "Humor can be dissected as a frog can, but the thing dies in the process and the innards are discouraging to any but the pure scientific mind.