‘Colorless green ideas sleep furiously‘ is a sentence composed by linguist Noam Chomsky in his 1957 book ‘Syntactic Structures’ as an example of a sentence that is grammatically correct, but semantically nonsensical. The term was originally used in his 1955 thesis ‘Logical Structures of Linguistic Theory.’
Although the sentence is grammatically correct, no obvious understandable meaning can be derived from it, and thus it demonstrates the distinction between syntax (linguistic rules) and semantics (symbolic meaning). As an example of a category mistake (a property is ascribed to a thing that could not possibly have that property), it was used to show inadequacy of the then-popular probabilistic models of grammar, and the need for more structured models.
The sentence can be given an interpretation through polysemy (the capacity for a sign to have multiple related meanings). Both ‘green’ and ‘colorless’ have figurative meanings, which allow colorless to be interpreted as ‘nondescript’ and green as ‘immature.’ The sentence can therefore be construed as ‘nondescript immature ideas have violent nightmares,’ a phrase with less oblique semantics. In particular, the phrase can have legitimate meaning too, if green is understood to mean ‘newly-formed’ and sleep can be used to figuratively express mental or verbal dormancy.
Writers have attempted to provide the sentence meaning through context, the first of which was written by Chinese linguist Yuen Ren Chao. A literary competition was held at Stanford University in 1985, in which the contestants were invited to make Chomsky’s sentence meaningful using not more than 100 words of prose or 14 lines of verse. An example entry from the competition, from C.M. Street, is: ‘It can only be the thought of verdure to come, which prompts us in the autumn to buy these dormant white lumps of vegetable matter covered by a brown papery skin, and lovingly to plant them and care for them. It is a marvel to me that under this cover they are laboring unseen at such a rate within to give us the sudden awesome beauty of spring flowering bulbs. While winter reigns the earth reposes but these colorless green ideas sleep furiously.’
There is at least one earlier example of such a sentence, and probably many more. The pioneering French syntactician Lucien Tesnière came up with the French sentence ‘Le silence vertébral indispose la voile licite’ (‘The vertebral silence indisposes the licit sail’). The 1925 game of ‘cadavre exquis’ (‘exquisite corpse’) is a method for generating nonsense sentences. It was named after the first sentence generated, ‘Le cadavre exquis boira le vin nouveau’ (‘the exquisite corpse will drink the new wine’).
In the popular game of ‘Mad Libs,’ a chosen player asks each other player to provide parts of speech without providing any contextual information, and these words are inserted into pre-composed sentences with a correct grammatical structure, but in which certain words have been omitted. The humor of the game is in the generation of sentences which are grammatical but which are meaningless or have absurd or ambiguous meanings (such as ‘loud sharks’). The game also tends to generate humorous double entendres.
There are doubtlessly earlier examples of such sentences, possibly from the philosophy of language literature, but not necessarily uncontroversial ones, given that the focus has been mostly on borderline cases. For example, followers of logical positivism (verificationists) held that ‘metaphysical’ (i.e. not empirically verifiable) statements are simply meaningless; e.g. German philosopher Rudolf Carnap wrote an article where he argued that almost every sentence from Heidegger was grammatically correct, yet meaningless. Of course, some philosophers who were not logical positivists disagreed with this.
Philosopher Bertrand Russell used the sentence ‘Quadruplicity drinks procrastination’ to make a similar point; W.V. Quine took issue with him on the grounds that for a sentence to be false is nothing more than for it not to be true; and since quadruplicity doesn’t drink anything, the sentence is simply false, not meaningless.
Another approach is to create a syntactically-correct, easily parsable sentence using nonsense words; a famous such example is ‘The gostak distims the doshes.’ Lewis Carroll’s ‘Jabberwocky’ is also famous for using this technique, although in this case for literary purposes. In Russian schools of linguistics, the ‘glokaya kuzdra’ (a meaningless but grammatically correct Russian language phrase) has similar characteristics.
Other arguably ‘meaningless utterances’ are ones that make sense, are grammatical, but have no reference to the present state of the world, such as ‘The King of France is bald,’ since there is no King of France today.
The Daily Omnivore 