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Philosophy of Language

Chomsky and Knowledge of Language

Ming Liu
Zhejiang Institute of Administration
Xin Sheen Liu
Syracuse University

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ABSTRACT: The linguistic theory of Chomsky has changed the long, traditional way of studying language. The nature of knowledge, which is closely tied to human knowledge in general, makes it a logical step for Chomsky to generalize his theory to the study of the relation between language and the world-in particular, the study of truth and reference. But his theory has been controversial and his proposal of "innate ideas" has been resisted by some empiricists who characterize him as rationalist. In our view, these empiricists make a mistake. In the present paper we attend to his position regarding linguistics as a science of mind/brain, which we believe is an important aspect of his theory that has not been paid enough attention or understood by his opponents. In turn, this will help to clarify some of the confusions around his theory. Finally we will discuss some of the debatable issues based on the outlines we draw.

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Chomsky's linguistic theory is based on the following empirical facts: "child learns language with limited stimuli", or the problem of poverty of evidence. (1) The input during the period of a natural language acquisition is circumscribed and degenerate. The output simply cannot be accounted for by the learning mechanism only, such as induction and analogy on the input. The output and input differ both in quantity and quality. A subject knows linguistic facts without instruction or even direct evidence. These empirical facts, "knowledge without ground", (2) are expressed: "Knowledge of language is normally attained through brief exposure, and the character of the acquired knowledge may be largely predetermined." (3)

This predetermined knowledge is some "notion of structure", in the mind of the speaker , which guides the subject in acquiring a natural language of his own. For a subject to know a natural language is for him to have a certain I-language. Language acquiring, in terms of I-language, corresponds to the change of a subject's mind/brain state. To know the language L is for the subject's (H's) mind/brain, initially to be in a state So, to be set to a certain state SL. (4) One task of the brain sciences will be to explain what it is about H's brain (in particular, its language faculty) that corresponds to H's knowing L.

He makes an important hypothesis that universal grammar (UG). UG is a characterization of these innate principle of language faculty, I-language. (5) He then postulates some detailed structure of UG. It is a system of conditions on grammars, constraints on the form and interpretation of grammar at all levels, from the deep structures of syntax, through the transformational component, to the rules that interpret syntactic structures semantically and phonetically. The study of linguistic universals, which is classified as formal or substantive, is the study of the properties of UG for a natural language. (6) Substantive universals concern the vocabulary for the description of language and a formal linguistic universal involve the character of the rules that appear in grammars and the ways in which they can be interconnected. Language-acquisition device uses primary linguistic data as the empirical basis for language learning to meet explanatory adequacy that is defined in UG, and to select one of the potential grammars, which is permitted by UG.

Chomsky then makes another two explicit hypothesis, "pure" speech community and a common grammar. (1) A "pure" speech community excludes contradictory choices for certain of options permitted by UG. (2) the property of mind described by UG is a species characteristic, common to all humans.

The hypothesis (2) implies that the study of one language, such as English, may provide crucial evidence concerning the structure of some other language. Acquisition of language then, is a matter of adding to one's store of UG rules, or modifying this system, as new data are processed. (7)

The nature of knowledge of language, which is closely tied to human knowledge in general, makes it a logical step for Chomsky to generalize his theory. The linguistic theory for special 'Plato problem' can be applied to 'Plato's problem' to knowledge in general, providing that an empirical evidence of such problem for a certain knowledge. He says, his innate principle includes syntax, phonology, and morphology, and semantics. By 'semantics' he means the study of the relation between language and the world — in particular, the study of truth and reference. (8) At the same time, he also generalizes his idea of UG, especially the process of parameter determination in acquiring a particular natural language for a subject. "This result of this process of parameter determination and periphery formation is a full and richly articulated system of knowledge. ...The same may well be true of large areas of what might be called 'commonsense knowledge and understanding'". (9) The first generalization, generalization of 'Plato's problem' to knowledge in general, is correct. The second generalization, seems to us, is too hasty. The advances in neural science and mathematics have produced new theory on complex systems. For a vast complicated system as human brain, which is tremendously flexible and which processes abstract concepts at many different levels, the theory of parameter determination over-simplifies the problem we are facing.


Chomsky proposed, in our view, a plausible theory of language. The different approaches between E-language and I-language may be similar to the Brahe and other's observational astronomy, which collected a vast body of data, and Ptolemy, Copernicus, and Kepler's model of planetary motion, even though the details of the model might be questionable. Chomsky's first generalization is also a legitimate step. But his proposal of "innate ideas" has been resisted by some empiricists, and he is characterized as rationalist. In our view, those empiricists make a mistake. In order to clarify this issue we will cite Chomsky's statements in spite of somewhat redundancy.

Chomsky attempts to develop a theory of linguistics as a discipline of natural sciences or physical sciences, which are empirically based. He specifically objects to 'Abstract-linguistics' (10) and he maintains that the boundary between linguistics and natural sciences will shift or disappear. The theory of mind aims to determine the properties of the initial state So and each attainable state SL of the language faculty, and the brain sciences seek to discover the mechanisms of the brain that are the physical realizations of these states. (11) Eventually, the linguistics and the brain science will converge. Chomsky uses the term 'mechanism', which refers to the physical mechanism. (12) He says, one task of the brain sciences, is to discover the mechanisms of brain that are the physical realization of the state SL. What he means by physical realization is the physically encoded mental state on the brain. "In contrast to E-language, the steady state of knowledge (I-language) attained and the initial state So are real elements of particular mind/brains, aspects of the physical world, where we understand mental states and representations to be physically encoded in some manner." (13) Chomsky's UG is biologically determined (14) principles too. Chomsky seems to use 'physically' and 'biologically' interchangeable. In this aspect Chomsky's universals that are biologically realized and physically encoded in brain, are different from Descarte's innate ideas.

Chomsky rejects the fictional and abstract objects and, especially, rejects the suggestion that knowledge of language should be taken to be an abstract "Platonic" entity. He says; "Knowing everything about the mind/brain, a Platonist would argue, we still have no basis for determining the truths of arithmetic or set theory, but there is not the slightest reason to suppose that there are truths of language that would still escape our grasp." (15) He differentiates linguistics from mathematics and emphasizes the empirical aspect of linguistics and its relationship to brain sciences; therefore, the justification of his theory is not only a theoretical matter, but also an empirical that relies on the results of brain science. Based on Chomsky's positions on the nature of his linguistics theory, we conclude that he has been mistaken as a rationalist. In the next section, we will discuss some of the debates on this subjects and other related issues.


One of the reason that he is regarded as a rationalist might be that Chomsky tries to differentiate himself from the linguistic behaviorism and he emphasizes some of reasonable core of "rationalism" to make a statement that my "sausage-making machines" (16) is not tabula rasa, but has complex, dedicated parts and structure. The other reason is the tradition of the rationalist philosophy of language, philosophical grammar. (17) He is not satisfied with the explanatory power of the descriptive grammar. Philosophical grammar is "typically concerned with data not for itself but as evidence for deeper, hidden organizing principles,..." (18) However, it may be surprising, his term 'rationalism' is equivalent to 'natural science', He states that the issue of rationalist philosophy of language "is not between descriptive and prescriptive grammar, but between description and explanation, between grammar as 'natural history' and grammar as a kind of 'natural philosophy' or, in modern terms, 'natural science.'" (19) He particularly criticizes the lack of physical, empirical aspects of Cartesian rationalism. (20)

Rationalism stressed the power of reason as opposed to empirical facts and used deductive reasoning as the basis for their knowledge system. Chomsky's theory is an empirical science and his method is largely based on linguistic empirical data. Therefore, Chomsky's theory is not rationalist in the classical sense. Some of his opponents (Quine, Wells) confuse what Chomsky is claiming and what he is doing. (21)

Understanding of Chomsky's position on those issues, some of the objections to his theory become automatically invalid, Goodman (22) raises a question. How does Chomsky start from some subtle difference in linguistics and then moves on to innate ideas? "I know what a horse with spirit is, but not what the spirit is without the horse." (23) This UG is not something that "a spirit without a horse" at all.

On the other hand, Chomsky's theory is empirical, but different from behaviorism linguistics. On the issue of "innate structure", Harman does not accept Chomsky's theory of innate structures. He said: "I view linguistics, it is closer to both anthropology and the behavioral sciences than he would apparently allow." (24) Quine argues: "This indisputable point about language is in no conflict with latter-day attitudes that are associated with the name of empiricism, or behaviorism. (25) There are two major differences between behaviorism and Chomsky's theory. Behaviorism treats a complex system as a black box, a functional mechanism. If two black box function exact the same, behaviorism and functionalism regards them exact the same. This is Quine's so-called 'enigma doctrine'. He says, "English speakers obey, in this sense, any and all of the extensionally equivalent systems of grammar that demarcate the right totality of well-formed English sentences." (26) However, Chomsky's "theories of grammar and UG are empirical theories" and his systems of grammar is physically encoded in some manner. The development of brain science will discover the very physical structure of human brain, and there can be only one of a set of "extensionally equivalent systems of grammar" is correctly attributed to the speaker-hearer as a property that is the same as that is physically encoded, where some other one merely happens to fit the speaker's behavior but does not correctly represent the physical facts. The second difference is reflected by the relationship between I-language and E-language. E-language, as the traditional behaviorist linguistics, deals with steady-state language, or mature language; while I-language in Chomsky's theory specifies not only the internal characteristics of language, but also deals with a dynamic process, language acquiring process, from initial state So to the steady state SL. (27) E-language is independent of a individual's history, while I-language explains the language aspect of individual's history. This dynamic process puts more constraints on the characteristics of the languages. I-languages may reach the same steady state SL and realize the steady state languages that have "extensionally equivalent systems of grammar"; while these I-languages may specify different dynamic processes that reach SL. These processes differentiate I-languages one another and some of them can be proved to be wrong theories regarding the language acquisition process. Therefore, extensionally equivalent systems of grammar in the traditional grammar sense is not necessarily equivalent in terms of I-language.

Nagel questioned whether the initial contribution of the organism to language-learning is properly described as knowledge. (28) Dummett questions the concept of unconscious knowledge. (29) He holds that there is an extremely important innate capacity but it would not called innate knowledge in either case. Chomsky introduces "cognize" in trying to resolve the issue, which we think it might be superficial. In computer science, a computation can be either realized through software, which is written in computer language, or through hardware, which is built by the logic circuits composed of physical parts. Both functions exactly the same. If we can do an extrapolation or analogy, ideas might be realized through abstract symbol systems or through neural-network. The two mode of structures may have effects on the recognizability. This is a speculation. But our point is that UG is proposed as hypothesis, and if the 'notion of structure' is correct, other hypothesis may be assumed on what kind of structure is and how the structure operates. The final settlement relies on new development of brain sciences.

UG as a hypothesis raises questions about to what extend the hypothesis correctly captures the structure of brain. Danto says:

"...to what extent does the innate structure of language formation sink into the world, giving it linguistic form, or the form of our language(s)? So far as LA is universal, we live perforce in the same world if the structure of our world reflects the structure of language. Obviously, something produced by means of a different LA would not be recognizably a language, nor would the world correlative with this, if there is this correlatively, be recognizably the world. A wholly different language or a wholly different world would be unintelligible, but is the very idea unintelligible?". (30)

Chomsky treats the innate idea as a fixed form (common grammar hypothesis), which resembles rationalist doctrine of ideas; while his attempts in providing a natural science of language is not consistent with such hypothesis. In this aspect, Herbert Spencer (Principle of Psychology) might be right that innate ideas, such as adopt form of thought, like the perception of space and time, or the notions of quantity and cause, which Kant supposed innate, are merely instinctive ways of thinking; and as instincts are habits acquired by the race but native to the individual, so these categories are mental habits slowly acquired in the course of evolution, and now part of our intellectual heritage. In Spencer's word, "the inheritance of accumulating modifications". If this is correct, chimpanzee and human ability in communication and maybe language can be bridged in principle, and the study of chimpanzee's brain would help to discover the innate structure physically encoded in a certain manner too.

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The authors are grateful to Professor Philip L. Peterson, Syracuse University, for his many comments and remarks.


Chomsky, Language and Mind, Harcourt Brace Jovanovich Inc., 1968.

Chomsky, N., "Methodological Preliminaries," Aspect of the Theory of Syntax, 1970, pp.26-40.

Chomsky, N., Knowledge of Language, Praeger, 1986.

Danto, "Semantical Vehicles, Understanding, and Innate Ideas", Language and Philosophy, New York University Press, 1969, pp.122-137.

Goldman, A.I., "Innate Knowledge", Innate Ideas, University California Press, 1966.

Goodman, N., "The Emperor's New Ideas", Language and Philosophy, New York University Press, 1969, pp.138-142

Harman, "Linguistic Competence and Empiricism," Language and Philosophy, New York University Press, 1969, pp.143-151.

Nagel, T., "Linguistics and Epistemology", Language and Philosophy, New York University Press, 1969, pp.171-181.

Quine, W.V.O., "Linguistics and Philosophy", Language and Philosophy, New York University Press, 1969, pp.95-98.

Quine, W.V.O., "Methodological Reflections on Current Linguistic Theory," Semantics of Natural Language, Humanities Press, 1972.


(1) Chomsky, 1986, pp.8-9.

(2) Chomsky, 1986, pp.11-12.

(3) Chomsky (1968, p.ix) actually has a machine in his mind, which analogous to the language acquisition device: "An engineer faced with the problem of designing a device meeting given input-output conditions would naturally conclude that the basic properties of the output are a consequence of the design of the device."

(4) Chomsky, 1986, p.22.

(5) Chomsky, 1986, p.40.

(6) Chomsky, 1970, p.341.

(7) Chomsky, 1986, pp.24-25.

(8) Chomsky, 1986, p.44.

(9) Chomsky, 1986, p. 222.

(10) "There does exist what we have called an internalized language and that it is a problem of the natural sciences to discover it." "In the sciences, at least, disciplines are regarded as conveniences, not as ways of cutting nature at its joints or as the elaboration of certain fixed concepts; and their boundaries shift or disappear as knowledge and understanding advance. In this respect, the study of language as understood in the discussion above is like chemistry, biology, solar physics, or the theory of human vision." (Chomsky, 1986, pp.33-35).

(11) Chomsky, 1986, p.38.

(12) "Linguistics, conceived as the study of I-language and So, becomes part of psychology, ultimately sciences insofar as mechanisms are discovered that have the properties revealed in these more abstract studies; indeed, one would expect that these studies will be a necessary step toward serious investigation of mechanisms."( Chomsky, 1986, p.27).

(13) Chomsky's statements of past might be confusing, such as "NOT 'brain programmed', rather mind has inborn capacities". We tend to interpret his theory based on his latest book Knowledge of Language (1986).

(14) Chomsky, 1986, p.24.

(15) Chomsky, 1986, p.33. He obviously try to distance his theory from Plato's ideas: "One is not mislead thereby into believing that the subject matter of rational mechanics is an entity in a Platonic heaven, and there is no more reason to suppose that that is true in the study of language." (1986, p.36) "There seems no obvious sense in populating the extra-mental world with corresponding entities, nor any empirical consequence or gain in explanatory force in doing so." (1986, p. 45).

(16) Danto, 1969.

(17) Philosophical grammar is "very much like current generative grammar, developed in self-conscious opposition to a descriptive tradition that interpreted the task of the grammarian to be merely that of recording and organizing the data of usage-a kind of natural history." (Chomsky, 1970)

(18) Chomsky, 1968, p.15.

(19) Chomsky, 1968, p.15.

(20) "...the far-reaching studies of language that were carried out under the influence of Cartesian rationalism suffered from a failure to appreciate either the abstractness of those structures that are 'present to the mind' when an utterance is produced or understood, or the length and complexity of the chain of operations that relate the mental structures expressing the semantic content of the utterance to the physical realization." (Chomsky, 1968, p.25)

(21) It must be confusing why he chooses lining up with rationalism. His early paper talked about Cartesian linguistics, but the latest book does not touches it at all, except the note related so-called 'Cartesian problem'. We can only sense that he is shifting his claim from the early ones.

(22) Goodman, 1969, p.138.

(23) Goodman, 1969, p.140. He misunderstands Chomsky's 'idea': "What Chomsky means by 'idea' is hard to determine." schematisms? "And since a theory may be embodied in one language or in many languages, but can hardly exist apart from languages, how could it be in the mind prior to language? What are those ideas? (Goodman, 1969, p.141)

(24) He adds an interesting points: "Nevertheless, I think that what is significant in his paper is the fact that he believes that a genetic account is relevant to certain fundamental epistemological questions lying at the foundation of language." (Harman, 1969, p.170)

(25) Quine, 1969, p.95. Also Lewis, Davison, Searle (Chomsky, 1986).

(26) Quine, 1972.

(27) The state SL is attained by setting parameters of So in one of the permissible ways, this is essential part of what is "learned," yielding the core, and adding a periphery of marked exceptions on the basis of specific experience, in accordance with the markedness principles of So.

(28) Nagel, 1969, p.172.

(29) Chomsky, 1986, p.269.

(30) Danto, 1969, p.136.

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