When Pigs Fly
Li and I just presented a paper at CogSci 2006, in which we argued that there are many ways in which a language can mark counterfactuality. One is to violate the semantic constraint or world knowledge. The example we gave was … "when pigs fly". This is a plain present tense sentence (clause to be precise), but you know whatever the message is in the main clause, it should NOT be interpreted literally. The reason being "Pigs fly" flies in face with the common sense.
There are many versions of Pigs Fly:
- "Pigs fly": gHits = 581K
- "Pigs can fly": gHits = 121K
- "Pigs could fly": gHits = 50K
- …
The plain version, "when/if pigs fly…" is particularly interesting because it doesn’t have any modal verbs or anything else special. In other words, it unmarked, except for the semantics. A semantic violation, alone, is enough to tip you the counterfactual reading of the sentence.
This page tells the possible etimology of the phrase:
"IF A PIG HAD WINGS, IT COULD FLY - What you say is just wishful thinking; it can never happen. The saying has been traced back to ‘Proverbs of Scotland’ (1862). The Walrus in ‘Alice’s Adventures in Wonderland’ (1865) by Lewis Carroll questioned ‘whether pigs had wings.’ First attested in the United States in ‘Green Thicket World’ (1934) by H. Vines. The adage is found in varying forms: If a pig (pigs) had wings, one could fly; If that happens, then pigs can fly; When pigs fly, that’s when, etc. It may be reversed: Pigs could fly if they had wings. As a rejoinder to the suggestion that something impossible may happen, it is usually abbreviated to ‘when pigs fly’ or ‘if bunny rabbits grow wings.’." From the "Random House Dictionary of Popular Proverbs and Sayings" by Gregory Y. Titelman (Random House, New York, 1996).
For "pigs fly" to work, two conditions must be met. The semantic violation must be unambiguous; try "when kakapos fly". In addition, as a code for a different reading of the underlying message, it had better be on the codebook of both sides of the communicative channel. Whistling shrimps are just as rare as flying pigs, but as an expression it may be less effective to many. For those of us who are ignorent of the 100+ history of the phrase, "if pigs fly" is just one of those sayings that does nothing other than marking counterfactuality.
All these are to say that I wish this was out a few days earlier; would have been great for our poster:
