The first few pages of this book declare a general attitude, wholly admirable in combining the firmest commitment to rationality with intellectual humility, that contrasts not only with the widespread irrationalism of our day but with the equally repellent scientism usually opposed to it. The book is divided into two parts, the first a revision of a lecture course given in 1978 and again in 1979, and the second consisting of two single lectures, both previously published. Part I presents a continuous argument, while the two chapters of Part II restate the same position in slightly different ways. Part I, in particular, is to a large extent polemical: Chomsky cites a great many criticisms of his work, and other expressions of views contrary to his own, and replies to them. The polemical mode of philosophical writing is not his forte.
There are two worthwhile ways to write philosophical polemics, exemplified, at their best, by Wittgenstein and by Frege respectively. The first is to enter deep into the mind of your opponent, to bring out the full power of the motives prompting him to say what he does, to present his case better than he does himself, and then to explain why it has to be rejected. The second is to ignore what can be said in its favour, and concentrate upon delivering a crushing blow, a knock-down refutation from which it can never recover. To attempt the former method risks leaving the reader unconvinced that you have really disproved your opponent’s position: but to attempt the second risks his suspecting that you have missed the true point. Chomsky achieves success in neither of these ways. Though always courteous, he manifests little sympathy with the thought of those he is criticising: his rejoinders often boil down to saying that they have begged the question, or are appealing to prejudice rather than to rational grounds, without any recognition that there is a genuine force to their contentions or a genuine problem to be resolved. Yet his arguments, though never negligible, seldom amount to a decisive refutation; the reader is not left thinking, apropos of his critics: ‘Whatever may be the truth of the matter, it cannot be that.’
This is not to say that the book is not of value. Chomsky is surely right in thinking that there has been a persistent misunderstanding between himself and many of his critics, among whom are numbered linguists and psychologists as well as philosophers. If, in this book, he succeeds in understanding those critics no better than they have understood him, he has made explicit the substance of the disagreement and has brought out its far-reaching importance. Chomsky of course insists that his work in linguistics is an empirical, scientific enterprise. In the present book he is not concerned, save by way of illustration, to expound his linguistic theories or to argue for them against rival theories of the same kind, but to defend their scientific character and their coherence; these questions, though crucial for a scientist to be able to answer, are themselves philosophical ones.
There are two principal issues with which the book is concerned and to which its author repeatedly returns. One is his celebrated thesis that our mastery of language is to a high degree innate. This is not the mere truism that we have an innate capacity to learn language, as, for example, gorillas do not: it means that what we do, in acquiring language, is not exactly learning, as this is usually conceived. We are born with a propensity to speak one out of a restricted range of possible languages. Given that it has to be selected from this restricted range, our experience provides a sufficient basis for acquiring our mother tongue; it would not do so if it had to be selected from among all possible languages. This thesis is of philosophical interest, because of its bearing on the concept of learning: but it is in itself an evidently empirical thesis, with no very great philosophical consequences. As such, it is very much subordinate to the other thesis on which Chomsky lays great stress in this book: namely, that mastery of a language consists of unconscious knowledge. I will concentrate exclusively on this latter thesis.
Unconscious knowledge consists in a ‘mental structure consisting of a system of rules and principles that generate and relate mental representations of various types’. Such a mental structure may be inaccessible to consciousness. This does not mean merely that it need not constitute explicit knowledge which the subject has formulated to himself or can immediately formulate when prompted. It need not even be implicit knowledge in the sense of something he can recognise and assent to when offered a formulation of it: one who has the knowledge may not be, in any circumstances, in any better position to say that he has it than anyone else. Chomsky is uninterested in whether such an unconscious mental structure is rightly called ‘knowledge’ in the commonly accepted sense: what concerns him is that a concept of cognition covering everything from fully explicit knowledge to wholly unconscious possession of such structures is required for a characterisation of linguistic competence.
Unsurprisingly, many have objected to this conception; Chomsky is in his turn surprised, and blandly insists that his thesis has been misunderstood or rejected without due reason. A natural query is in what sense the structure and the ‘representations’ generated by it are said to be mental. Chomsky explains that, in speaking of mind, he does not mean to imply ‘that there is a res cogitans as a “second substance” apart from body’ – an immaterial medium, in Wittgenstein’s phrase. That, however, is only to repudiate one possible answer to the question in what sense the postulated structure is mental. In some of Davidson’s influential writings on the philosophy of language (not mentioned in Chomsky’s book), he claims that the proper method is to ask, for any given language, what body of knowledge would be required for someone to be able, in virtue of his explicit possession of that knowledge, to speak and understand the language. Here it is not maintained that any actual speaker really has such a body of knowledge, however tacitly or implicitly, but only that, by answering this question, we obtain an illuminating account of what is involved in speaking and understanding the language: a means of illumination which is, indeed, somewhat roundabout unless ability to speak a language actually does involve having such knowledge. Davidson would thus not claim that a ‘theory of meaning’, arrived at by answering his question, explains how the speaker is able to understand the language, i.e. what renders him capable of doing so: it at most provides a somewhat oblique characterisation of his linguistic ability. Though not citing Davidson, Chomsky does respond to various critics who hold that his hypothesis of unconscious knowledge of a system of rules is devoid of explanatory power, amounting to no more than a systematic description of the practice of speaking the language. There are two distinct positions entailing a denial of explanatory power to Chomsky’s theory. One is: there can be no such thing as unconscious knowledge; a speaker does not know the system of rules governing the language, but merely acts as would someone who knew those rules and could apply them sufficiently rapidly. The other is: one may legitimately describe a speaker as unconsciously knowing the rules governing the language, but, in doing so, one is saying no more than that he speaks, and responds to the speech of others, in accordance with those rules: hence no hypothesis has been advanced, nor any explanation given. The difference between these positions is of little interest to Chomsky. He repudiates both: his theory is an explanatory hypothesis, not a systematisation of facts open to view.
If the theory is a hypothesis, however well confirmed, there has to be an alternative, however indistinctly glimpsed. It is not, of course, in Chomsky’s interest to suggest very convincing alternatives, and he is prone to mention only ludicrous ones such as the use of black magic or our all being controlled by demons: if such absurdities were the only conceivable alternatives to his theory, there would surely be little substance to the claim that it is an empirical hypothesis. Chomsky comes closest to giving a substantial answer when he discusses the general notions of knowledge-how and of practical skill. The distinction between practical and theoretical knowledge (in Ryle’s terminology, between knowing-how and knowing-that) is a very old one in philosophy: but Chomsky remarks more than once that knowing-how ‘involves a crucial intellectual component’ – i.e. that knowing how to do something, properly so called, involves knowing that certain things are so. It might seem to follow that any practical ability, such as the ability to ride a bicycle, must involve knowledge-that, even if unconscious. Chomsky rejects this conclusion: for him, ‘bicycle riding is a skill’; ‘there is no reason to suppose that the rules’ which govern it ‘are represented in a cognitive structure’. Thus, although we ordinarily speak of ‘knowing how to ride a bicycle’, Chomsky finds it doubtful whether this ability ought to be described as an instance of knowing-how. This, too, is for him an empirical question. It may be that ‘the bicycle rider does have a representation of certain physical principles in his mind and uses them to plan or compute his next act’: it is just that there is no good reason for supposing this to be so.
It is a pity that Chomsky did not explore this case more fully: if he had, we should have a clearer grasp of what he takes to be the evidence that an unconscious knowledge of grammatical rules governs our production and interpretation of sentences of our mother tongue. He several times discusses his grounds for holding that, if we have such knowledge, it must be in large part innate, but he never expressly adduces evidence that our linguistic competence is based on unconscious knowledge at all, rather than being a skill, in his sense of that term. Presumably he thinks that the movements of the bicyclist are explicable in terms of a fairly simple feed-back. Such an explanation would surely be inadequate to account for skill in handling a boat or a racing motor-cycle. Such skills involve conscious judgment, based on conscious knowledge: their interest lies in the fact that the subject does not, and to a large extent could not, formulate in words the thoughts leading to those judgments, or the knowledge on which they are based.
Such examples suffice to show that we should be wrong to infer, from someone’s inability to say what he knows, that his knowledge is not conscious: which is not to say that we can give a clear account of unverbalised thought. Chomsky’s assumption is that our knowledge of our mother tongue is ‘represented somehow in our minds, ultimately in our brains, in structures that we can hope to characterise abstractly, and in principle quite concretely, in terms of physical mechanisms’. ‘When I use such terms as “mind”, “mental representation”, “mental computation”, and the like,’ he explains, ‘I am keeping to the level of abstract characterisation of the properties of certain physical mechanisms.’ Unconscious knowledge is thus a physiological state, presumably a state of the brain: in locating it ‘in our minds’, we are acknowledging the purely abstract character of the account which is the best we can at present give of it. Much of the book is occupied with defence of the claim that this is a straightforward empirical hypothesis, comparable with the postulation of thermonuclear reactions within the Sun, and warranted upon the evidence. A characterisation of some physiological system is not, however, qualified as psychological merely by being abstract or schematic: i.e. by omitting to specify the actual mechanisms involved. What gives Chomsky’s theory its psychological character is its use of psychological terms like ‘computation’ and ‘knowledge of a rule’.
Chomsky exhibits some impatience with the distinction between mind and body: the question is not whether his theory is to be classified as a contribution to psychology or to neurophysiology, however, but of how we are to understand his notion of unconscious knowledge. He rejects an account of knowledge in terms of capacities, in favour of the view that it consists in an internal mental structure, arguing that the structure may remain intact even though the capacity in which it normally issues is for some reason impeded. Moreover, he suspects our familiar concept of knowledge of being incoherent, whereas he is assured of the coherence of his own broader notion of cognition, which requires neither grounds nor accessibility: ‘cognising has the structure and character of knowledge, but may be... inaccessible to consciousness.’ The idea here is that if knowledge consists in the possession of a certain accessible mental structure acquired under certain conditions, we may generalise to a notion of cognition, taken as consisting in the presence of that mental structure, no matter how acquired, and whether or not accessible or even presently issuing in any capacity.
The difficulty is, however, that we have no idea what structure and character knowledge, conceived as an internal state, may have, apart from the structure of what is known. We are aware that access to knowledge may be temporarily inhibited, but we nevertheless identify it solely by its manifestations; and we cannot suppose the manifestations of unconscious knowledge to be exactly like those of conscious knowledge without reducing consciousness to an epiphenomenon, prompting the senseless question what advantage there is to us in being conscious at all. Chomsky plainly intends his cognitive structures to be interpreted more literally than such obvious, though fruitful, metaphors as ‘coded genetic instructions’, but in saying that to take knowledge as consisting in a capacity is to mistake evidence for criteria, he uses too crude a constrast, since, knowing nothing in advance about the postulated inner structures, we could not identify them as cognitive ones save by the connection with their manifestations. We therefore need much more than Chomsky offers us about how, in general, unconscious knowledge is manifested if we are to understand or evaluate his theory.
Thus, even if his opponents are wrong to regard ‘unconscious knowledge’ as self-contradictory, like ‘unconscious pain’, Chomsky is not warranted in treating it as no more perplexing than the notion of a largely unconscious physiological process like digestion. While he alludes to the problems that currently exercise philosophers concerning knowledge – namely, how it is to be distinguished from belief – he shows no concern with the far deeper problem of what it is to have a thought at all. Plato explained thinking as speaking silently to oneself, but this is certainly not in general correct. Analytical philosophy is nevertheless founded upon the idea that, since language is the most perspicuous vehicle of thought, we can best explain what thought is by explaining what it is for the words in which thought is expressed to have the meanings that they do. The popular reaction that this is to trivialise philosophy is dead wrong: such an inquiry goes far deeper than any previous philosophy has attempted to do. It is only when we take for granted someone’s understanding of a language that it appears relatively unproblematic to attribute to him thoughts, beliefs and knowledge; the deep problems open up when we ask in what that understanding consists. Earlier philosophers sometimes offered ludicrously inadequate answers to that question; more often, they simply assumed that there is no problem in supposing thought to occur, within the mind, divested of its linguistic clothing.
The analytical approach supplies an impelling motive for regarding linguistic ability as a skill in Chomsky’s sense, one involving no cognitive component: for if it be supposed that to understand a language is to know that certain things are so, the possession of that knowledge cannot without circularity be taken as in turn embodied in some verbal formulation. Chomsky displays no awareness of this motivation, but it is incumbent on him to do so. Since his concern is primarily scientific, we cannot reproach him with failing to offer an alternative line of attack on the question what it is to have a thought: but since, by denying that linguistic competence is a skill, he blocks the attack on it through language, he has no right to such assurance that the notion of unconscious knowledge is self-explanatory. If we cannot explain what it is to have a conscious thought, we cannot indeed prove that the notion of unconscious computation is not coherent: but we can hardly be certain that it is. Chomsky remarks in passing that reason ‘devoid of the projective mechanisms of the computational system of human language is severely impaired, almost mute’. He seems here to acknowledge severe limitations to thought without a linguistic vehicle: this only makes it the more problematic that he assigns such complex tasks to the unconscious processes that enable us to construct and interpret sentences.
The prospects for explaining linguistic ability as a skill in Chomsky’s sense are dim: it is precisely for this reason that philosophers such as Davidson do not attempt to do so directly, but in terms of the body of knowledge which would impart that ability to its possessor. Knowledge of a language does not resemble an ordinary practical skill: one who cannot ski may perfectly well know what it is to ski, whereas one who does not know Spanish does not know what it is to speak Spanish, and would be unable to tell for sure whether others were speaking Spanish or not. A good deal of conscious knowledge is required for the knowledge of a language, as Chomsky himself remarks. Someone may be in doubt whether he has interpreted a sentence correctly, but he can seldom be unsure whether he has put any interpretation on it at all: yet if understanding were simply a practical ability – say, to respond appropriately – there would be no reason why he should be in a position to say whether or not he has understood. A speaker knows the meanings of words and sentences of the language: ‘knows the meaning of’ is not an idiom for ‘understands’, but must be construed as ascribing genuine knowledge. It is on the basis of such knowledge that we say what we do: for speech is ordinarily a highly conscious activity, an activity of rational agents with purposes and intentions.
For reasons such as these, Chomsky is almost certainly right in treating knowledge of language as a genuine instance of knowledge, as well as in holding practical knowledge, properly so called, to have a large theoretical component. That does not entitle him, however, to dismiss the problems that then arise by declaring such knowledge inaccessible: for one thing, we need an account of how unconscious knowledge issues in conscious knowledge. Chomsky is principally concerned with knowledge of grammatical rules, on which our understanding of sentences in part depends. Conscious knowledge of grammar is very often acquired by instruction, and hence verbally formulated: it is therefore easy to suppose, in this connection, that what is not thought in words must be unconscious. This will not do for knowledge of meaning, which, though it is conscious knowledge, does not consist in our being able to state the meaning. We therefore stand in need of an account of conscious knowledge, and conscious thought, not carried by a linguistic vehicle. Until we can give such an account, we cannot say how much of our linguistic ability can be explained in terms of conscious but unverbalised knowledge; nor can we say how compelling the case for its resting upon unconscious knowledge, or for there being such a thing at all, can be made to appear.