Colorless green ideas sleep furiously
Encyclopedia
Noam Chomsky
Avram Noam Chomsky is an American linguist, philosopher, cognitive scientist, and activist. He is an Institute Professor and Professor in the Department of Linguistics & Philosophy at MIT, where he has worked for over 50 years. Chomsky has been described as the "father of modern linguistics" and...
in his 1957 Syntactic Structures
Syntactic Structures
Syntactic Structures is an seminal book in linguistics by American linguist Noam Chomsky, first published in 1957. It laid the foundation of Chomsky's idea of transformational grammar...
as an example of a sentence
Sentence (linguistics)
In the field of linguistics, a sentence is an expression in natural language, and often defined to indicate a grammatical unit consisting of one or more words that generally bear minimal syntactic relation to the words that precede or follow it...
that is grammatically correct (logical form
Logical form
In logic, the logical form of a sentence or set of sentences is the form obtained by abstracting from the subject matter of its content terms or by regarding the content terms as mere placeholders or blanks on a form...
) but semantically nonsensical
Nonsense
Nonsense is a communication, via speech, writing, or any other symbolic system, that lacks any coherent meaning. Sometimes in ordinary usage, nonsense is synonymous with absurdity or the ridiculous...
. The term was originally used in his 1955 thesis "Logical Structures of Linguistic Theory". Although the sentence is grammatically correct, no understandable
Understanding
Understanding is a psychological process related to an abstract or physical object, such as a person, situation, or message whereby one is able to think about it and use concepts to deal adequately with that object....
meaning can be derived from it, and thus it demonstrates the distinction
Distinction
*Distinction may refer to:* Distinction is a social force that places different values on different individuals....
between syntax
Syntax
In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....
and semantics
Semantics
Semantics is the study of meaning. It focuses on the relation between signifiers, such as words, phrases, signs and symbols, and what they stand for, their denotata....
. As an example of a category mistake
Category mistake
A category mistake, or category error, is a semantic or ontological error in which "things of one kind are presented as if they belonged to another", or, alternatively, 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
Language model
A statistical language model assigns a probability to a sequence of m words P by means of a probability distribution.Language modeling is used in many natural language processing applications such as speech recognition, machine translation, part-of-speech tagging, parsing and information...
, and the need for more structured models.
Details
The full passage says:While the meaninglessness of the sentence is often considered fundamental to Chomsky's point, Chomsky was only relying on the sentences' having never been spoken before. Thus, even if one were to prescribe a likely and reasonable meaning to the sentence, the grammaticality
Grammaticality
In theoretical linguistics, grammaticality is the quality of a linguistic utterance of being grammatically well-formed. An * before a form is a mark that the cited form is ungrammatical....
of the sentence is concrete despite being the first time a person had ever uttered the statement, or any part thereof in such a combination. This was used then as a counter-example to the idea that the human speech engine was based upon statistical models, such as a Markov chain
Markov chain
A Markov chain, named after Andrey Markov, is a mathematical system that undergoes transitions from one state to another, between a finite or countable number of possible states. It is a random process characterized as memoryless: the next state depends only on the current state and not on the...
, or simple statistics of words following others.
Attempts at meaningful interpretations
The sentence can be given an interpretation through polysemyPolysemy
Polysemy is the capacity for a sign or signs to have multiple meanings , i.e., a large semantic field.Charles Fillmore and Beryl Atkins’ definition stipulates three elements: the various senses of a polysemous word have a central origin, the links between these senses form a network, and ...
. Both green and colorless have figurative meanings, which allow us to interpret colorless 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. An equivalent sentence would be "Newly formed bland ideas are inexpressible in an infuriating way."
Writers have attempted to provide the sentence meaning through context, the first of which was written by Chinese linguist Yuen Ren Chao
Yuen Ren Chao
Chao Yuen Ren was a Chinese American linguist and amateur composer. He made important contributions to the modern study of Chinese phonology and grammar....
. A literary competition was held at Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
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 labouring 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 colourless green ideas sleep furiously.
Statistical challenges
Fernando Pereira of the University of Pennsylvania
University of Pennsylvania
The University of Pennsylvania is a private, Ivy League university located in Philadelphia, Pennsylvania, United States. Penn is the fourth-oldest institution of higher education in the United States,Penn is the fourth-oldest using the founding dates claimed by each institution...
has fitted a simple statistical Markov model to a body of newspaper text, and shown that under this model, "Furiously sleep ideas green colorless" is about 200,000 times less probable than "Colorless green ideas sleep furiously".
This statistical model defines a similarity metric, whereby sentences which are more like those within a corpus in certain respects are assigned higher values than sentences less alike. Pereira's model assigns an ungrammatical version of the same sentence a lower probability than the syntactically correct form demonstrating that statistical models can learn grammaticality distinctions with minimal linguistic assumptions. However, it is not clear that the model assigns every ungrammatical sentence a lower probability than every grammatical sentence. That is, "colorless green ideas sleep furiously" may still be statistically more "remote" from English than some ungrammatical sentences. To this, it may be argued that no current theory of grammar is capable of distinguishing all grammatical English sentences from ungrammatical ones.
Related and similar examples
There is at least one earlier example of such a sentence, and probably many more. The pioneering FrenchFrance
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
syntactician
Syntax
In linguistics, syntax is the study of the principles and rules for constructing phrases and sentences in natural languages....
Lucien Tesnière
Lucien Tesnière
Lucien Tesnière was one of the most prominent and influential French linguists.Tesnière was born in Mont-Saint-Aignan on May 13, 1893...
came up with the French sentence
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
"Le silence vertébral indispose la voile licite" ("The vertebral silence indisposes the licit sail").
The game of cadavre exquis
Exquisite corpse
Exquisite corpse, also known as exquisite cadaver or rotating corpse, is a method by which a collection of words or images is collectively assembled. Each collaborator adds to a composition in sequence, either by following a rule Exquisite corpse, also known as exquisite cadaver (from the original...
(1925) 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
Mad Libs
Mad Libs is a phrasal template word game where one player prompts another for a list of words to substitute for blanks in a story, usually with funny results...
", a chosen player asks each other player to provide parts of speech without providing any contextual information (e.g., "Give me a proper noun", or "Give me an adjective"), 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
Logical positivism
Logical positivism is a philosophy that combines empiricism—the idea that observational evidence is indispensable for knowledge—with a version of rationalism incorporating mathematical and logico-linguistic constructs and deductions of epistemology.It may be considered as a type of analytic...
held that "metaphysical" (i.e. not empirically verifiable
Empirical validation
An empirical validation of a hypothesis is required for it togain acceptance in the scientific community. Normally this validation is achieved by the scientific method of hypothesis commitment, experimental design, peer review, adversarial review, reproduction of results, conference presentation...
) statements are simply meaningless; e.g. Rudolph Carnap wrote an article where he argued that almost every sentence from Heidegger
Martin Heidegger
Martin Heidegger was a German philosopher known for his existential and phenomenological explorations of the "question of Being."...
was grammatically correct, yet meaningless. Of course, some philosophers who were not logical positivists disagreed with this.
The philosopher Bertrand Russell
Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS was a British philosopher, logician, mathematician, historian, and social critic. At various points in his life he considered himself a liberal, a socialist, and a pacifist, but he also admitted that he had never been any of these things...
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.
Examples like Tesnière's and Chomsky's are the least controversially nonsensical, and Chomsky's example remains by far the most famous.
John Hollander
John Hollander
John Hollander is a Jewish-American poet and literary critic. As of 2007, he is Sterling Professor Emeritus of English at Yale University...
wrote a poem titled "Coiled Alizarine" in his book, The Night Mirror. It ends with Chomsky's sentence.
Clive James
Clive James
Clive James, AM is an Australian author, critic, broadcaster, poet and memoirist, best known for his autobiographical series Unreliable Memoirs, for his chat shows and documentaries on British television and for his prolific journalism...
wrote a poem titled "A Line and a Theme from Noam Chomsky" in his book, Other Passports: Poems 1958-1985. It opens with Chomsky's second meaningless sentence and discusses the Vietnam War.
Another approach is to create a syntactically-correct, easily parseable sentence using nonsense words; a famous such example is "The gostak distims the doshes
Gostak
Gostak is a meaningless noun that is used in the phrase "the gostak distims the doshes", an example of how it is possible to derive meaning from the syntax of a sentence even if the referents of the terms are entirely unknown. This can be seen in the following dialogue:In Amazing Stories, Dr...
". Lewis Carroll
Lewis Carroll
Charles Lutwidge Dodgson , better known by the pseudonym Lewis Carroll , was an English author, mathematician, logician, Anglican deacon and photographer. His most famous writings are Alice's Adventures in Wonderland and its sequel Through the Looking-Glass, as well as the poems "The Hunting of the...
's Jabberwocky
Jabberwocky
"Jabberwocky" is a nonsense verse poem written by Lewis Carroll in his 1872 novel Through the Looking-Glass, and What Alice Found There, a sequel to Alice's Adventures in Wonderland...
is also famous for using this technique, although in this case for literary purposes. In Russian schools of linguistics, the glokaya kuzdra
Glokaya kuzdra
Glokaya kuzdra is a reference to a meaningless but grammatically correct Russian language phrase, similar to the English language phrase "Gostak". It was suggested by Russian linguist Lev Shcherba. The full phrase is: "Гло́кая ку́здра ште́ко будлану́ла бо́кра и кудря́чит бокрёнка"...
example is known.
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 (see definite description
Definite description
A definite description is a denoting phrase in the form of "the X" where X is a noun-phrase or a singular common noun. The definite description is proper if X applies to a unique individual or object. For example: "the first person in space" and "the 42nd President of the United States of...
).
See also
- Poverty of the stimulusPoverty of the stimulusIn linguistics, the poverty of the stimulus is the assertion that natural language grammar is unlearnable given the relatively limited data available to children learning a language, and therefore that this knowledge is supplemented with some sort of innate linguistic capacity...
- Universal grammarUniversal grammarUniversal grammar is a theory in linguistics that suggests that there are properties that all possible natural human languages have.Usually credited to Noam Chomsky, the theory suggests that some rules of grammar are hard-wired into the brain, and manifest themselves without being taught...
- Moore's paradoxMoore's paradoxMoore's paradox concerns the putative absurdity involved in asserting a first-person present-tense sentence such as 'It's raining but I don't believe that it is raining' or 'It's raining but I believe that it is not raining'. The first author to note this apparent absurdity was G.E. Moore...
- Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo