Dorothy Parker once quipped about a Yale Prom, “If all the girls attending it were laid end to end, I wouldn’t be at all surprised.” Herman Mankiewicz said of Orson Welles: “There, but for the grace of God, goes God”. (It has also been attributed to Sir Winston Churchill, as a put-down of Sir Stafford Cripps, but Herman Mankiewicz got there first.) Some unknown comic has written: “Where there’s a will, I want to be in it” and another has created “Mary had a little lamb; the midwife was surprised.”
What connects these witticisms is that their endings are unexpected, a violation of expectations whose surprise provokes laughter. It’s a useful trick for comedy writers. Paraprosdokian is the term for it that has become moderately well known in recent decades; it’s particularly widely used online, probably because mentioning it is a good excuse for repeating choice quotes from witty writers.
The word hasn’t yet reached any dictionary that I know of and that includes the recent revision of the letter P in the Oxford English Dictionary, though the editor of the Macquarie Dictionary of Australia tells me that it will be in its next revision. That’s led some, including the Canadian broadcaster and writer Bill Casselman, to argue that it’s not a proper term in rhetoric: “The word paraprosdokian was made up by some semiliterate doofus late in the 20th century”. He challenged those who thought otherwise “to show me one single citation for the word paraprosdokian earlier than 1950 CE”. No problem:
The humourous incongruity and unconscious cynicism of their utterance, and the paraprosdokian of their dialogue, with their perilous approach to caricature, all seem to show that Mrs. Craigie is developing a talent all her own for rendering bucolic character.
The Echo (Middx.), 10 Nov. 1896. This is in a long review (on the front page: different times) of the novel The Herb Moon, by John Oliver Hobbes, pen name of Pearl Mary-Teresa Craigie.
And, in a piece written by Sir Compton Mackenzie three decades later:
It is long since I have sat at the feet of this minstrel; and I quote from memory; but I think another verse of the same poem thus illustrated the same paraprosdokian or concluding jerk of disappointment.
Illustrated London News (London), 18 Jul. 1931.
The phrase para prosdokian occurs in classical Greek literature, meaning “contrary to expectations”, but at some point the two words have been run together. Who first did this is untraceable, but as the earliest recorded use that I’ve unearthed was in Die Sprache als Kunst by Gustav Gerber, dated 1884, I suspect this German philosopher of language to be responsible.
Paraprosdokian looks odd to us because the -ian ending is more commonly found in adjectives in English than in nouns (though a few, such as comedian and tragedian, do contain it). In the Greek phrase, prosdokian is an inflected form of prosdokia, “expectation” — whether for good or ill, hence Sir Compton Mackenzie’s comment — where the final n is the marker of the accusative case that conventionally followed the preposition para. The English word would be better as paraprosdokia, using the root form of the noun.
That does occasionally appear in scholarly literature, though like the other form it’s not in any of my dictionaries, and the established use of paraprosdokian means it’s too late to convince anybody to change.