"What is humour????", asked Charlie Chaplin once. He answered his own question with aknowledged authority, "it is a kind of gentle and benevolent custodian of the mind which prevents us from being overwhelmed by the apparent seriousness of life." While this tells us why laughter is important; does it tell us why we laugh??
I hope we can rule out the perverse idea that we laugh at what is inferior because we are happy to feel superior. This is an idea that has been advocated by the likes of Al Capp (creator of Lil' Abner). Yet what sort of custodian is this? Such philosophy grows out of the very premise that life is indeed as serious as it appears to be.
Humour is a creature of strong emotion, and is the relief of strong emotion; being like the antidote brewed from the poison. Look at the sequence of playing peek-a-boo with a baby. The player brings thier face slowly out of hiding from behind a chair or handkerchief. At first the babe is taut with suspense, anticipation, perhaps even the beginning of fear....then there is recognition, relief; and with the relief, laughter.
Is this different than the sensation we feel when the clown ducks just before the ladder goes whooshing over his head? Each near miss grapples with our emotion as we fear for the clown. The suspense builds and then is released with each near miss. As the danger never passes, the overall suspense grows and grows till at last, contact is made. We laugh. Well it is still relief: the only relief we can expect at this point from the suspense that has been building up. Yet it is not a cruel laughter; for the clown makes the pain unreal, comic by his exaggeration. It is an unreality he shakes off within moments and so, overcomes. As we watch the fool, we cannot possibly see ourselves viewing an inferior. For what we watch is a champion. The fool for our sake grapples with the very essence of strife. In a way, he suffers in our stead. But just as surely, he overcomes in our behalf. For as we watch him dispell the reality of life's little menaces, that in life which threatens to overwhelm us as well becomes dispelled.
Reality is dispelled in part through dispelling of illusion. And comedy largely involves the simultaneous creation and dispelling of the same illusion. Consider any of the classic skits with two men in a horse suit. The comedy in the act is not in how well they impersonate a horse but in how imperfectly they do so. A perfect imitation would not be as funny as an imperfect one. In Shakespearian plays during Elizabethan times the female roles were played by young boys, The pretense was near perfect and the show continued riding that undispelled illusion. In plays such as "As you Like It!" The female lead (played then by a boy) disguises herself as a young man or boy. It is an imperfect illusion because the writer is sure to leave reminders to the audience that the boy is really a woman (while the actor took care that there is no reminder that the woman is really a boy). The mutually accepted illusion, the near perfect one, is merely a convention. The imperfect illusion is a living contradiction of reality. Make a fake cow suit out of brown hide and with good acting it may be funny. Make one from an old checkered table cloth and with any moderate acting it is halarious. Part of our senses see what is real, part what is unreal. We laugh.
Traditionally, comedy can be divided into six parts, blows, falls, knavery, surprise, mimicry and stupidity. We can concede that in part, at least, stupidity involves the emotions of superiority and inferiority. Although it also at times invokes the sense of wonder. Falls involve the emotion of pity, blows those of anger and of fear. Surprise in itself is an emotion. Knavery may be subdivided into different castes; cockoldry/roguery and stealing through strategem (especially in the case of drink or one of a kind items. In drink this can be that the universal traditions of hospitality excuse the crime; while one of a kind items are perhaps not properly own by any.) Mimicry as mentioned the perfection of the farce is not what is funny but what its flaws are. When Rosalyn in "As you Like It" is funny, it is because we know she is Rosalyn, a woman in scenes in which her imperfect disguise reminds us of her womanhood. What is going on around the pretended man is reacting not with the illusion of the male disguise but the reality of the female that we know is beneath.