Chomsky, Noamin full Avram Noam Chomsky  ( born Dec. 7, 1928 , Philadelphia, Pa., U.S.American linguist and political activist who founded transformational-generative grammar, an original and highly influential system of linguistic analysiswhose theories of language revolutionized the field of linguistics from the mid-20th century and exerted a profound influence on philosophy, psychology, and cognitive science.

Chomsky was introduced to the study of linguistics by his father, a Hebrew scholar who worked within the framework of historical linguisticsof Hebrew. He studied under the linguist Zellig S. Harris at the University of Pennsylvania and , where he earned bachelor’s (1949) and master’s (1951) degrees there. The early stages of Chomsky’s Many elements of his early theories of language appear in his manuscript Logical Structure of Linguistic Theory (published 1975), which he wrote while a Junior Fellow at Harvard University in 1951–55. A chapter of this work, “Transformational Analysis,” formed his University of Pennsylvania Ph.D. dissertation , “Transformational Analysis” (1955). After receiving his degree, he began teaching modern languages and linguistics at the joined the faculty of the Massachusetts Institute of Technology (MIT) in 1955. He , where he became a full professor there in 1961 and . He was appointed Ferrari P. Ward professor Professor of foreign languages Modern Languages and linguistics Linguistics in 1966 .

Chomsky set out his theory of transformational grammar in Syntactic Structures (1957), a book that revolutionized the development of theoretical linguistics. In this work he broke with the dominant structural school, which held that language is essentially a system of syntactical and grammatical habits established by means of training and experience. Chomsky, by contrast, argued that human beings have an innate facility for understanding the formal principles underlying the grammatical structures of language. It is this innate capacity that explains how young children, after hearing the speech of their elders, are able to infer the grammatical rules underlying ordinary sentences and then use those rules to generate an infinite number and variety of sentences that they had never heard before.

In analyzing the innate ability to construct these “generative grammars,” Chomsky distinguished between two levels of structure in sentences: “surface structures,” which are the actual words and sounds used, and “deep structures,” which carry a sentence’s underlying meaning. People are able to create and interpret sentences by generating the words of surface structures from deep structures according to a set of abstract rules that, though limited in number, allow for unlimited variation. Chomsky called these rules “grammatical transformations,” or “transformational rules.” He argued that these rules are basically the same in all languages and correspond to innate, genetically transmitted mental structures in human beings.

Chomsky’s work virtually defined the methods of linguistic analysis used in the second half of the 20th century. His assertions about humans’ innate knowledge of language have not been widely accepted, however. Chomsky’s other books on linguistics include and Institute Professor in 1976.

In the 1940s and ’50s the study of linguistics in the United States was dominated by the school of American structuralism. According to the structuralists, the proper object of study for linguistics is the corpus of sounds of a given language, which they call “primary linguistic data.” The task of the linguist is to construct a grammar of the language by applying to the primary linguistic data a series of complex analyses that would isolate the significant units of sound in the language (phonemes) and identify their permissible combinations into words and ultimately sentences. In keeping with their strict empiricism, the structuralists argued that in order to be genuinely scientific the grammar must be mechanically extractable by these analyses from the primary linguistic data and must not include reference to unverifiable and mysterious mental entities such as “meanings.” For similar reasons, structuralists proposed or were sympathetic to behaviourist accounts of language learning, in which linguistic knowledge amounts to merely a set of dispositions, or habits, acquired through conditioning and without the aid of any language-specific mental structures.

In contrast to structuralism, Chomsky’s approach, as outlined in his first major publication, Syntactic Structures (1957), and refined considerably in several works since then, is thoroughly mentalistic, insofar as it takes the proper object of study for linguistics to be the mentally represented grammars that constitute the native speaker’s knowledge of his language and the biologically innate “language faculty,” or Universal Grammar, that allows the (developmentally normal) language learner as a child to construct a rich, detailed, and accurate grammar of the language to which he is exposed. Children acquire languages in relatively little time, with little or no instruction, without apparent difficulty, and on the basis of primary linguistic data that are necessarily incomplete and frequently defective. (Once they reach fluency, children routinely produce sentences they have never heard before, and many of the sentences produced by adults in their environment contain errors of various kinds, such as slurs, false starts, run-on sentences, and so on.)

These facts, according to Chomsky, demonstrate the inadequacy of behaviourist theories of language learning, which typically do not postulate mental structures beyond those representing simple induction and other “general learning strategies.” Given the primary linguistic data to which speakers are exposed, it is impossible on behaviourist assumptions to construct a “descriptively adequate” grammar—i.e., a grammar that generates all and only the sentences of the language in question. The ultimate goal of linguistic science for Chomsky is to develop a theory of Universal Grammar that is “explanatorily adequate” in the sense of providing a descriptively adequate grammar for any natural language given exposure to primary linguistic data.

Chomsky’s work in linguistics hastened the decline of behaviourism in psychology, prompted a revival of interest in rationalist theories of knowledge in philosophy, and spurred research into the innate rule systems that may underlie other domains of human thought and knowledge.

Chomsky is also known around the world as a political activist, though his views have received little attention in the mass media of the United States. Since the 1960s he has written numerous works and delivered countless lectures and interviews on what he considers the antidemocratic character of corporate power and its insidious effects on U.S. politics and foreign policy, the mass media, and the behaviour of intellectuals.


Among Chomsky’s works on the subject of linguistics are Aspects of the Theory of Syntax (1965), Cartesian Linguistics (1966), The Sound Pattern of English (with Morris Halle, 1968), Language and Mind (1968


, enlarged ed.



The Logical Structure of Linguistic Theory (1975), and

Reflections on Language (1975)

. Language and Responsibility (1979) discusses the relation of language and politics and the ramifications of generative grammar. His later books, including


further examine those subjects.Chomsky also became well known for his opposition to the United States’ involvement in the Vietnam War during the late 1960s and early ’70s. His books criticizing American foreign policy and the role played by giant corporations and the mass media include American

and The Minimalist Program (1995).


American Power and the New Mandarins (1969),

Towards a New Cold War (1982), Pirates & Emperors (1986), On Power and Ideology (1987


and World Orders, Old and New (1994).

Year 501: The Conquest Continues (1993).

General studies include James McGilvray, Chomsky: Language, Mind and Politics (1999); and Neil Smith, Chomsky: Ideas and Ideals (1999). Some useful anthologies on various aspects of Chomsky’s work are James McGilvray, The Cambridge Companion to Chomsky (2002); Carlos Otero, Noam Chomsky: Critical Assessments, 4 vol. (1994); and Gilbert Harman, On Noam Chomsky: Critical Essays (1982). Milan Rai, Chomsky, Politics (1995), is the best overall summary of Chomsky’s political views. James Peck (ed.), The Chomsky Reader (1988), contains a good selection of Chomsky’s basic political works and an interview in which Chomsky discusses his career. Robert Barsky, Noam Chomsky: A Life of Dissent (1997), is an intellectual biography focusing on Chomsky’s politics.