A thing is funny when — in some way that is not actually offensive or frightening — it upsets the established order. Every joke is a tiny revolution. If you had to define humour in a single phrase, you might define it as dignity sitting on a tin-tack. Whatever destroys dignity, and brings down the mighty from their seats, preferably with a bump, is funny. And the bigger the fall, the bigger the joke. It would be better fun to throw a custard pie at a bishop than at a curate.

George Orwell (1903-1950) English writer [pseud. of Eric Arthur Blair]

“Funny, But Not Vulgar,” Leader Magazine (1945-07-28)
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Written in December 1944. More discussion of this quotation here.