Noam Chomsky: Norbert Hornstein
Noam Chomsky: Norbert Hornstein
Noam Chomsky: Norbert Hornstein
Norbert Hornstein
In Edward Craig (ed.), Routledge Encyclopedia of Philosophy, London, 1998
Fish swim, birds fly, people talk. The talents displayed by fish and birds rest on specific biological
structures whose intricate detail is attributable to genetic endowment. Human linguistic capacity
similarly rests on dedicated mental structures many of whose specific details are an innate
biological endowment of the species. One of Chomskys central concerns has been to press this
analogy and uncover its implications for theories of mind, meaning and knowledge.
This work has proceeded along two broad fronts.
First, Chomsky has fundamentally restructured grammatical research. Due to his work, the central
object of study in linguistics is the language faculty, a postulated mental organ which is
dedicated to acquiring linguistic knowledge and is involved in various aspects of language-use,
including the production and understanding of utterances. The aim of linguistic theory is to
describe the initial state of this faculty and how it changes with exposure to linguistic data.
Chomsky (1981) characterizes the initial state of the language faculty as a set of principles and
parameters. Language acquisition consists in setting these open parameter values on the basis of
linguistic data available to a child. The initial state of the system is a Universal Grammar (UG): a
super-recipe for concocting language-specific grammars. Grammars constitute the knowledge of
particular languages that result when parametric values are fixed.
Linguistic theory, given these views, has a double mission. First, it aims to adequately
characterize the grammars (and hence the mental states) attained by native speakers. Theories
are descriptively adequate if they attain this goal. In addition, linguistic theory aims to explain
how grammatical competence is attained. Theories are explanatorily adequate if they show how
descriptively adequate grammars can arise on the basis of exposure to primary linguistic data
(PLD): the data children are exposed to and use in attaining their native grammars. Explanatory
adequacy rests on an articulated theory of UG, and in particular a detailed theory of the general
principles and open parameters that characterize the initial state of the language faculty (that is,
the biologically endowed mental structures).
Chomsky has also pursued a second set of concerns. He has vigorously criticized many philosophical
nostrums from the perspective of this revitalized approach to linguistics. Three topics he has
consistently returned to are:
Knowledge
Indeterminacy
of
language
and
and
under
its
general
determination
epistemological
in
linguistic
implications
theory
an
unbounded
domain
of
sentences.
(b) The child is exposed not to sentences but to utterances of sentences. These are imperfect
vehicles for the transmission of sentential information as they can be defective in various ways.
Slurred speech, half sentences, slips of the tongue and mispronunciations are only a few of the
ways
that
utterances
can
obscure
sentence
structure.
(c) Acquisition takes place without explicit guidance by the speech community. This is so for a
variety of reasons. Children do not make many errors to begin with when one considers the range
of logically possible mistakes. Moreover, adults do not engage in systematic corrections of errors
that do occur and even when correction is offered children seem neither to notice nor to care. At
any rate, children seem surprisingly immune to any form of adult linguistic intrusion (see Lightfoot
1982).
(d) Last of all, and most importantly, of the linguistic evidence theoretically available to the child,
it is likely that only simple sentences are absorbed. The gap between input and intake is
attributable to various cognitive limitations such as short attention span and limited memory. This
implies that the acquisition process is primarily guided by the information available in well-formed
simple sentences. Negative data (the information available in unacceptable ill-formed sentences)
and complex data (the information yielded by complex constructions) are not among the PLD that
guide the process of grammar acquisition. The child constructing its native grammar is limited to
an informationally restricted subset of the relevant data. In contrast to the evidence that the
linguist exploits in theory construction, the information the child uses in building its grammar is
severely restricted. This suggests that whenever the linguistic properties of complex clauses
diverge from simple ones, the acquisition of this knowledge cannot be driven by data. Induction is
insufficient as the relevant information is simply unavailable in the PLD.
The general picture that emerges from these considerations is that attaining linguistic competence
involves the acquisition of a grammar, and that humans come equipped with a rich innate system
that guides the process of grammar construction. This system is supple enough to allow for the
acquisition of any natural language grammar, yet rigid enough to guide the process despite the
degeneracy and deficiency of the PLD. Linguistic theorizing takes the above facts as boundary
conditions and aims both at descriptive adequacy (that is, to characterize the knowledge that
speakers have of their native grammars) and explanatory adequacy (that is, to adumbrate the fine
structure of the innate capacity) (see Language, innateness of).
Issues of descriptive and explanatory adequacy have loomed large in Chomskys work since the
beginning. Chomskys objection, for example, to Markov models of human linguistic competence
was that they were incapable of dealing with long distance dependencies exemplified by
conditional constructions in English and hence could not be descriptively adequate. His argument in
favour of a transformational approach to grammar rested on the claim that it allowed for the
statement of crucial generalizations evident in the judgments of native speakers and so advanced
the goal of descriptive adequacy (Chomsky 1957). Similarly, his influential critique (1959) of
Skinners Verbal Behavior consisted in showing that the learning theory presented therein was
explanatorily inadequate. It was either too vague to be of scientific value or clearly incorrect given
even moderately precise notions of stimulus or reinforcement.
The shift from the early Syntactic Structures (1957) theory to the one in Aspects of a Theory of
Syntax (1965) was also motivated by concerns of explanatory adequacy. In the earlier model the
recursive application of transformations allows for the generation of more and more complex
sentences from the sentences produced by the phrase structure component of the grammar. In
the Aspects theory, recursion is incorporated into the phrase structure component itself, and
removed from the transformational part of the theory (see Syntax 3). The impetus for this was the
observation that greater explanatory adequacy could be attained by grammars that had a level of
Deep Structure incorporating a recursive base component. In particular, Fillmore (1963) observed
that the various optional transformations in a Syntactic Structures theory always applied in a
particular order in any given derivation. This order is unexplained in a Syntactic Structures theory;
in Aspects it is deduced. Thus, the move to an Aspects-style grammar is motivated on grounds of
greater explanatory adequacy: introducing Deep Structure and moving recursion to the base allows
for a more restricted theory of Universal Grammar. All things being equal, restricting UG is always
desirable as it advances a central goal of grammatical theory; the more restricted the options
innately available for grammar construction, the easier it is to explain how language acquisition is
possible, despite the difficulties in the PLD noted above.
The same logic motivates various later additions to and shifts in grammatical theory. For example,
a major move in the 1970s was radically to simplify transformational operations so as to make their
acquisition easier. This involves eliminating any mention of construction-specific properties from
transformational rules. For example, an Aspects rule for passive constructions looks like (1), the
left-hand side being the Structural Description (SD) and the right hand side being the Structural
Change (SC):
X-NP1-V-NP2-Y->(1)X - NP2 - be + en V - by + NP1 - Y x
This rule would explain, for instance the grammaticality of the ball is kicked by John given that of
John kicks the ball. Observe that the SC involves the constants and by. The SD mentions
three general expressions, NP1, V and NP2 and treats these as part of the context for the
application of the rule. In place of this, Chomsky proposed eliminating the passive rule and
replacing it with a more general rule that moves NPs (Chomsky 1977, 1986). The passive rule in (1)
involves two applications of the Move NP rule, one moving the subject NP1 to the by phrase,
and another moving the object NP2 to the subject position. In effect, all the elements that make
the passive rule in (1) specific to transitive constructions are deleted and a simpler rule (Move
NP) replaces it.
There is a potential empirical cost to simple rules, however. The simpler a transformation the more
it generates unacceptable outputs. Thus, while a grammar with (1) would not derive was jumped
by John from John jumped, a grammar eschewing (1) and opting for the simpler Move NP rule is
not similarly restricted. To prevent overgeneration, therefore, the structure of UG must be
enriched with general grammatical conditions that function to reign in the undesired
overgeneration (Chomsky 1973, 1977, 1986). Chomsky has repeatedly emphasized the tension
inherent in developing theories with both wide empirical coverage and reasonable levels of
explanatory adequacy.
A high point of this research agenda is Chomskys Lectures on Government and Binding (1981). Here
the transformational component is reduced to the extremely simple rule Move a - that is, move
anything anywhere. To ensure that this transformational liberty does not result in generative
chaos, various additions to the grammar are incorporated, many conditions on grammatical
operations and outputs are proposed, and many earlier proposals (by both Chomsky and others) are
refined. Among these are trace theory, the binding theory, bounding theory, case theory, theta
theory and the Empty Category Principle. The picture of the grammar that Chomskys Lectures
presents is that of a highly modular series of interacting subsystems which in concert restrict the
operation of very general and very simple grammatical rules. In contrast to earlier traditional
How is this knowledge put to use?. The answer to the first question is given by a particular
generative grammar. Harolds knowledge of English is identified with Harolds being in a particular
mental/brain state. A descriptively adequate grammar characterizes this part of Harolds
mental/brain make-up. An answer to the second question is provided by a specification of UG and
the principles that take the initial state of the language faculty to the knowledgeable state on
exposure to PLD. Harold knows English in virtue of being genetically endowed with a language
faculty and having been normally brought up in an English-speaking community. Beyond this,
further issues of grounding are unnecessary. Issues of epistemological justification and grounding in
the data are replaced by questions concerning the fine structure of the initial state of the language
faculty and how its open parameters are set on the basis of PLD. The third question is answered by
outlining how linguistic knowledge interacts with other cognitive capacities and abilities to issue in
various linguistic acts such as expressing ones thoughts, parsing incoming speech and so on (see
Chomsky 1986).
How much does the language case tell us about epistemological issues in other domains? In other
words, should knowledge of quantum mechanics be analysed in a similar vein, that is, being in a
particular mental state, grounded in specific innate capacities and so on. Chomsky only makes
sparse comments on this general issue, but those he advances suggest that he believes that
knowledge in these domains should be approached in much the same way they are approached in
the domain of language. This suggests that humans have an innate science-forming capacity that
underlies our success in the few domains of inquiry in which there has indeed been scientific
success. As in the domain of language, this capacity is focused and modular rather than being a
general all-purpose tool and this, Chomsky speculates, might well underlie the patchiness of our
successes. Where we have the right biological propensities, we develop rich insightful theories that
far outpace the data from which they are projected. Where this mind/brain structure is lacking,
mysteries abound that seem recalcitrant to systematic inquiry. Stressing our cognitive limits is a
staple of Chomskys general epistemological reflections. If humans are part of the natural world we
should expect there to be problems that fall within our cognitive grasp and mysteries that lie
outside it. The rich theoretical insights allowed in the natural sciences are the result of a chance
convergence between properties of the natural world and properties of the human mind/brain (see
Chomsky 1975).
3 Indeterminacy and underdetermination
Knowledge of language, Chomsky has argued, presents a strong argument in favour of traditional
rationalist approaches to mind and against traditional empiricist approaches (see Learning 1;
Rationalism). In particular, learning is treated as more akin to growth and the course of
acquisition is seen more as the unfolding of innate propensities under the trigger of experiential
input than as the result of the shaping effects of the environment. This rationalist perspective is
now quite common and this is largely due to Chomskys efforts. Chomsky has consistently warned
against empiricist prejudices in philosophy, and in no instance more strongly than in his critique of
Quines methodological remarks on linguistics (for example, see Quine 1960).
Chomsky takes Quine to be arguing that linguistic investigations are beset with problems greater
than those endemic to inquiry in general. Whereas empirical investigation in general suffers from
underdetermination of theory by evidence, linguistic study is beset with the added problem of
indeterminacy (see Radical translation and radical interpretation 2-3). Indeterminacy differs
from standard inductive underdetermination (see Underdetermination) in that where there is
indeterminacy there is no real question of right choice among competing proposals. Chomsky
interprets Quine as arguing that determining truth in the study of language differs from the
problem of determining truth in the study of physics (Chomsky 1975: 182-3).
In reply, Chomsky (1969) argues that Quines thesis rests on classical empiricist assumptions about
how languages are acquired. Quine, he argues, supposes that humans have an innate quality space
with a built-in distance measure tuned to certain simple physical correlates. In addition, certain
kinds of induction in this space are permitted. Beyond this, however, language-learning is a matter
of association of sentences to one another and to certain stimuli through conditioning. Further,
one cannot make significant generalizations about language or common-sense theories, and the
child has no concept of language or of "common-sense" prior to this training (Chomsky 1969: 54-5,
63).
Chomsky notes that Quine provides no evidence to support these assumptions. Nor can there be any
good evidence to support them if the nature of the learning problem in the domain of language is
characterized as Chomsky has argued it must be. Chomsky concludes that Quines thesis of the
indeterminacy of translation amounts to an implausible and quite unsubstantiated empirical claim
about what the mind brings to the problem of acquisition of language (or of knowledge in general)
as an innate property (Chomsky 1969: 66). Stripped of these tendentious empirical assumptions,
Quine fails to show that indeterminacy is anything other than the familiar problem of
underdetermination of theory by evidence as applied to linguistics. Chomsky (1996) has since
argued that the ultimate source of many critiques of the mental sciences in general and linguistics
in particular (including Quines indeterminacy thesis) is a kind of methodological dualism that takes
humans to be separate from the natural world. This dualism is manifest in the a priori constraints
that philosophers place on explanations in the mental sciences, which would be regarded as
inappropriate if applied to the physical sciences.
In this vein Chomsky asks, for example, why access to consciousness is so often taken to be crucial
in substantiating the claim that humans have I-language or follow rules. Suppose, he asks, we had a
theory that perfectly described what happens when sound waves hit the ear, stimulating the
performance system to access the cognitive system and construct a logical form that interacts with
other cognitive systems to yield comprehension, in so far as the language faculty enters into this
process. What more could be desired? The insistence that this entire process be accessible to
consciousness in order for the account to be credible, he argues, is a demand beyond naturalism, a
form of methodological dualism of dubious standing that would be summarily rejected if raised
elsewhere.
Or consider the oft-voiced suspicions concerning mentalist approaches in psychology. Many
philosophers are ready to accept these as perhaps temporarily necessary but ultimately, the view
seems to be, mentalist theories must reduce to physical ones to be truly legitimate. Chomsky
argues that this sentiment is another manifestation of methodological dualism and should be
rejected. First, it presupposes that there is a tenable distinction between the mental and the
physical. However, Chomsky argues that since Newton undermined the Cartesian theory of body by
showing that more occult forces were required in an adequate physics, mind-body dualism has
lost all grounding. Second, even if reduction were possible, reduction comes in many varieties and
there is little reason to believe that the contours of the reducing physical theory would be left
unaffected by the process. Since Newton, Chomsky notes, physical has been an honorific term
that signifies those areas in which we have some nontrivial degree of theoretical understanding.
The relevant scientific question is whether some theory or other offers interesting descriptions and
explanations. The further insistence that its primitives be couched in physical vocabulary is either
vacuous (because physical has no general connotation) or illegitimate (another instance of
methodological dualism).
The general conclusion Chomsky draws is that whatever problems linguistic theory encounters, it is
no more methodologically problematic than theories in other domains. He attributes the qualms of
philosophers to lingering empiricist dogma or an indefensible epistemological dualism.
4 I-language versus E-language
Given the aims of Chomskian linguistic theory, the proper objects of study are the I-languages
internalized by native speakers, rather than public E (xternal)-languages used by populations.
Chomsky denies that public E-languages are interesting objects of scientific study. Indeed he denies
that E-languages can be coherently specified as they simply do not exist. The proper objects of
inquiry are I-languages; I standing for intensional, internal and individual. An I-language is
individual in that each speaker has one. This focus turns the common wisdom on its head. Elanguages like English, Swahili and so forth are (at best) radical idealizations for Chomsky, or (at
worst) incoherent pseudo-objects. At best, E-languages are the intersection of the common
properties of various I-languages. Thus, for example, it is not that speakers communicate because
they have a language in common; rather wherever I-languages overlap communication is possible.
An I-language is internal in the sense of being part of a speakers individual mental make-up. It is
neither a Platonic object nor a social construct. Also, an I-language is intensional, not extensional.
Comprised as it is of an unbounded number of sentences, a language cannot be given except via a
specification of the function that generates them, that is a grammar for that language. Thus, it is
languages in intension, languages dressed in all of their grammatical robes, not simple
concatenations of words, that are the proper objects of scientific interest. One consequence of this
is that weak generative capacity (that is, the extensional equivalence of languages generated by
different grammars) is of dubious interest. In short, the shift from E-language to I-language turns
many long-standing questions around, raising some to prominence that were considered secondary
and relegating many that previously were considered crucial to the status of pseudo-questions.
Many philosophers have found Chomskys focus on I-language problematic. To illustrate, we will
consider an important philosophical critique and Chomskys reply.
Dummett (1986) argues against internalist approaches to language that they fail to provide an
account of notions like language of a community or community norms in the sense presupposed
by virtually all work in the philosophy of language and philosophical semantics. These notions,
Dummett claims, are required to provide a notion of a common public language which exists
independently of any particular speakers and of which native speakers have a partial, and
partially erroneous, grasp (see Language, social nature of 2).
The naturalistic study of language, Chomsky counters, has no place for a Platonistic notion of
language, a notion of language outside the mind/brain that is common to various speakers and to
which each speaker stands in some cognitive relation. The reason is that this Platonistic reification
rests on notions like language and community that are hopelessly under-specified. Asking if two
people speak the same language is, in Chomskys opinion, to ask a highly context-dependent
question - much like asking whether Boston is near New York. What counts as a community depends
on shifting expectations of individuals and groups. Human society is not neatly divided into
communities with languages and their norms. Thus, what counts as a community is too underspecified to be useful for theoretical purposes. Therefore, it is not a defect of linguistic theory that
these notions play no role within it.
From Chomskys perspective E-languages are epiphenomenal objects, if coherent at all. I-language
in its universal aspects is part of the human genotype and specifies one aspect of the human
mind/brain. Under the triggering effects of experience a particular grammar arises in the
mind/brain of an individual. From this perspective, universal grammar and the steady-state
grammars that arise from them are real objects. They will be physically realized in the genetic
code and the adult brain. E-language, in contrast, has a murky ontological status. Chomsky (1980)
argues that the priority of I-language cannot be reasonably doubted once we observe that
languages involve an infinite pairing of sounds and meanings. Given that language is infinite, it
cannot be specified except in so far as some finite characterization - a function in intension - is
provided. It might be possible to give some characterization to the notion a language used by a
population but only indirectly via a grammatical specification of the language. But this concedes
the priority of I-language as the claim unpacks into something like: each person in the relevant
population has a grammar in their mind/brain that determines the E-language. Thus, at best, an Elanguage is that object which the I-language specifies. However, even this might be giving too
much reality to E-languages, for there is nothing in the notion I-language that requires that what
they specify corresponds to languages as commonly construed, which is, things like French, English
and so on. It is consistent with Chomskys viewpoint that I-language never specifies any object that
we might pre-theoretically call a language. Whether this is indeed the case, the key point is to
realize that the move from grammar to language is a step away from real mechanisms to objects of
a higher degree of abstraction. I-language is epistemologically and ontologically hardier than Elanguage, much philosophical opinion to the contrary.
List of works
Chomsky, N. (1957) Syntactic Structures, The Hague: Mouton. (First work on Transformational
Grammar.)
Chomsky, N. (1959) Review of Verbal Behavior by B.F. Skinner, Language 35: 26-58.(A critique of
behaviourist approaches to learning.)
Chomsky, N. (1965) Aspects of a Theory of Syntax, Cambridge, MA: MIT Press.(Outlines the
Standard Model.)
Chomsky, N. (1969) Quines Empirical Assumptions, in D. Davidson and J. Hintikka (eds) Words
and Objections, Dordrecht: Reidel.
Chomsky, N. (1973) Conditions on Transformations, in S.R. Anderson and P. Kiparsky (eds) A
Festschrift for Morris Halle, New York: Holt, Rinehart & Winston.(Begins the move away from rulebased approaches to grammar.)
Chomsky, N. (1975) Reflections on Language, New York: Pantheon. (A good non-technical review of
the extended standard theory and various philosophical issues related to generative grammar.)
Chomsky, N. (1977) Essays on Form and Interpretation, Amsterdam: North Holland. (Essays in the
extended standard theory.)
Chomsky, N. (1980) Rules and Representations, New York: Columbia University Press.(Essays on
linguistics and philosophy.)