by Noam Chomsky
II.3 Naturalizing the study of language: biolinguistics
Those who construct naturalistic theories of specific subject matters generally aim to accommodate their specific science to at least one other natural science – perhaps a more general one, or a more specific one. This is just doing what any natural scientist does: accommodate physics to chemistry, for example, or accommodate major parts of biology to organic chemistry. Accommodating linguistics to biology has been one of Chomsky’s aims virtually from the beginning, but certainly it was an aim by the time he wrote CL. The primary issue was, and is, this: what does a child have at birth that allows him or her to acquire any natural language whatsoever under the conditions described by the poverty of the stimulus observations. Clearly, the child has something; call it “Universal Grammar” (UG). To accommodate language to biology, the obvious first question is what UG has in it – what UG must have, if the facts are to be explained. Or to put it another way, what is essential to human languages; what must all human infants have that the young of creatures that lack language lack? To answer that question, one must say what UG is – one must construct a theory of the “initial state” of the language faculty. Further, to have any chance of reaching accommodation with biology, one had better hope that it turns out that UG is not very complex and rich – that very little is needed to explain how having that essential element is sufficient to yield not just a language, but any natural language. For if it should turn out that UG is complex and rich, it will be very difficult to make sense of how the human genome could come to have a complex and rich ‘instruction set’ – the ‘information’ necessary, given minimal input, to yield any natural language. While accommodation was a desideratum from the start, the route to success did not become at all clear until after CL was written, not until the late 1970s and early 1980s. Since that time, there has been considerable progress in coming at least to understand the program (Chomsky calls it the “minimalist program”) needed to reach accommodation. No one can say with any confidence that they have the answer now, and that point is probably still a long way off. But, unlike the situation in the mid-1960s, it looks answerable.
Although progress in accommodation was a long way off when CL was written, the “standard” grammar of the time – found in Chomsky’s 1965 Aspects of the Theory of Syntax – made progress in reaching the other desiderata characteristic of naturalistic research. It is useful in reading CL to have in mind what had been accomplished at the time, and why the amount of progress made then made accommodation seem out of reach. In fact, one of the points of CL was to indicate how far things had come since the work of earlier RR efforts. More generally, indicating progress illustrates how fruitful for the scientific study of language it has proven to be to adopt the basic RR strategy and naturalize it. What looked earlier to be gaps in efforts to explain are filled and unanswered questions get answers. Apparently insurmountable problems become easy to deal with, unexplained structural features of languages have come to seem natural – natural necessities, even, given that language is a natural object. I will not detail any of this; to do so would require getting into the details of specific grammars and making this section far longer than it already is. Instead, I will focus on what Chomsky with Aspects in hand said in CL about what was wrong with the efforts of the Port-Royal grammarians in the seventeenth and eighteenth centuries. That might appear to be unfair; why not gauge progress over the work of linguists – including Chomsky – far closer to 1965? But, except for grammars advanced by Chomsky and his co-workers themselves – with the possible exception of von Humboldt, although he did not actually make an effort to construct a generative grammar – there are no moderately detailed RR candidate theories of language until Chomsky’s early 1950s Morphophonemics of Modern Hebrew and the mid-1950s (and massive) Logical Structure of Linguistic Theory. Comparing the progress of Aspects over what Chomsky did in Logical Structure would require going into great technical detail. Granted, he could have compared Aspects grammar to the grammars offered by what CL calls “modern” linguists (guided by principles outlined by Bloomfield, Joos. . .), or structuralists such as De Saussure. But these are empiricist efforts, and they are patently hopeless at making sense of either poverty or creativity observations. That would not illuminate progress in RR research strategy. Progress over Port-Royal efforts does: as CL indicates, the Port-Royal grammarians came up with something that invites comparison. They came up with observations and a few principles that looked surprisingly like what one finds in Aspects. Perhaps that is why in CL Chomsky explicitly compares what they accomplished with what had been accomplished in Aspects-type grammar.
In barest outline, the Port-Royal grammarians attempted to construct grammars for natural languages on RR assumptions about strategy. They assumed that there are universal features in the grammars of all languages and that linguistic productivity – putting words together to make endless numbers of sentences – can be described by appeal to a system of rules. And they thought of themselves as scientists (“philosophers”) of language, hoping to determine the nature of a system in the mind that humans alone have. Chomsky had no trouble rephrasing and articulating at least some of their observations and principles in terms he employed himself. For numerous examples, see CL’s “Deep and Surface Structure.” One helpful example appears early in that section in Chomsky’s discussion of how their grammar (and Aspect’s) could take the ‘deep’ forms God created the world, the world is visible, and God is invisible (or rather, abstract representations of these) and transform them by “transformational” rules (hence, “transformational grammar”) to yield the ‘surface’ form Invisible God created the visible world. The reader can look at the section for the details of this and other examples.
Summarizing Port-Royal efforts from the vantage point of Aspects and pointing to the limitations of what the Port-Royal grammarians managed to do, Chomsky remarks in the third paragraph from the end of CL’s section Description and Explanation in Linguistics:
The[se] philosophical [scientific, universal] grammarians considered a wide realm of particular examples; they tried to show, for each example, what was the deep structure that underlies its surface form and expresses the relations among elements that determine its meaning. To this extent, their work is purely descriptive. . . Reading this work, one is constantly struck by the ad hoc character of the analysis, even where it seems factually correct. A deep structure is proposed that does convey the semantic content, but the basis for its selection (beyond mere factual correctness) is generally unformulated. What is missing is a theory of linguistic structure that is articulated with sufficient precision and is sufficiently rich to bear the burden of justification. (My emphasis)
The Port-Royal grammarians made some progress in (informal) description, but they could not justify. To do that is to show how one can solve Plato’s Problem.
First, some points of agreement: Port-Royalists realized that anyone attempting a serious grammar for a natural language must construct a generative22 theory of that language in order to provide for the endless linguistic resources people display when they use language creatively. The Port-Royal grammarians aimed to produce such a grammar. Another point of agreement: they, like Chomsky, aimed for a universal (scientific, objective) grammar, and believed that only by offering such a grammar could one not just describe language, but hope to explain why it is the right grammar for a speaker’s language – why it, and not another one, ended up in the child’s mind. Still another: the overall ‘shape’ or ‘format’ of the Port-Royal grammars resembled in interesting ways the grammars Chomsky constructed in the mid-1960s. Chomsky at the time thought that all grammars for natural languages have the same format. Among other things, all consist of a “phrase structure grammar” which has the effect of assembling words into abstract structures that, after the operations of “obligatory transformations,” resemble what might be thought of as simple sentences, such as “God created the world.” These structures have a “semanti
c interpretation” – they are given a ‘meaning’. These Deep Structures can in turn be combined in more complex structures, and/or otherwise changed; the part of the grammar that ‘does’ this is the optional transformational component. The output of that set of operations is a “Surface Structure.” These transformed structures are in turn given a phonetic interpretation: they are assigned a ‘sound’. One of the aims of the Port-Royalists was to capture the intuition that while languages can differ a great deal in their sounds, they are fundamentally the same in meanings. That theme continued in Aspects, obviously.
How exactly, then, does Aspects improve on what the Port-Royal grammarians accomplished? One great improvement was in descriptive adequacy. Chomsky’s grammars are formalized, and explicitly articulate the relevant rules and principles, the ‘levels’ of a computation, and the relations between levels and elements. You cannot describe a language by listing sentences; you would have to provide an infinite list. The only adequate way to describe a language is to construct a formal theory (grammar) of it, one that states in explicit formal terms what the language’s rules or principles are. The Port-Royal grammarians did not manage that; their efforts lacked “sufficient precision,” as Chomsky notes. One must say explicitly what the phrase structure and transformational rules for a language are. If you do not, you cannot describe a language at all, nor decide whether your grammar is the correct one – that is, satisfy descriptive adequacy conditions. Of course, Chomsky had an advantage over the Port-Royalists; mathematics and other formal studies had advanced a great deal in the intervening centuries. But that does not diminish his contribution.
Another, more fundamental advance was in the primary task for those who want not only to describe, but to explain. While the Port-Royalists aimed in their attempt to produce a universal grammar to develop one that could explain as well as describe, what they offered – in part by virtue of lack of precision – could not explain why a child’s mind, given data under poverty of the stimulus conditions, selects grammar X as opposed to all the thousands of other possibilities. They could not really solve Plato’s Problem, or really even state it in an explicit way. Chomsky’s Aspects could at least state what needs to be done to solve Plato’s Problem, and it actually suggested a solution that now looks inadequate, but that at the time was the only one available. Clearly, then, Chomsky’s Aspects grammar was both descriptively and explanatorily more adequate than Port-Royal grammars.
Here in outline is the device Chomsky used in the mid-1960s to make sense of how the child’s mind automatically ‘selects’ grammar X as opposed to Y – that is, learns X as opposed to Y, given data D. Think of X and Y as sets of rules, both candidates as descriptions of language L or, more carefully, of the data available to the child’s mind. Which should the child’s mind choose? Introduce now an ‘internal’ simplicity measure: rule set X is better than Y to the extent that X has fewer rules than Y.23 If one can measure whether one grammar is better than another in this way, it does not stretch credulity very much to imagine that some internal and innate device in the child’s mind ‘chooses’ X over Y by applying such a measure. That is, it is plausible to assume that something in the child’s mind – not the child consciously choosing between alternatives – chooses and thereby acquires or learns X, given a choice between X and Y. Chomsky’s mid-1960s efforts to solve Plato’s Problem relied on this kind of postulated device. By doing so – by assuming an internal, innate mechanism to carry out the (relative) preference procedure – he was able to offer an explicit solution to Plato’s Problem that could plausibly be tied into some kind of choice mechanism. By saying what the choices are (choices between sets of rules), by quantifying the procedure, and by assuming that the procedure is carried out by some kind of innate automatically operating mechanism, he could at least state Plato’s Problem and outline how to go about solving it. Only by doing so could he or anyone else begin to think about how the language faculty and its growth could be accommodated to biology.
Lacking improved successor efforts, the grammars of the time were descriptively and explanatorily as adequate as they could be. There was also progress in other areas. They were also as universal and objective as they could be conceived to be at the time. In addition, they offered a way to conceive of how accommodation might be accomplished. And they were simple in both a theory-general sense and a theory-internal sense. By the standards of success in naturalistic research, then, Chomsky’s grammars made great progress over those provided by the Port-Royal grammarians.
While compared to Port-Royal grammar Chomsky’s Aspects UG was a considerable advance, compared to later work, Aspect’s UG displays many inadequacies. Some were apparent even at the time. A relative choice/learning procedure relies heavily on the assumption that something, somehow, constructs rule sets X and Y in the first place. While it appeared at the time to be possible to compress all natural languages into the same format, only a few had been investigated with any degree of precision, and even these few displayed multiple and – from the point of view of explaining acquisition – unsatisfying differences that the notion of a common format and some suggestions about innate grammar-constructing devices could not diminish. A substantial notion of universality looked out of reach: different languages alike only in ‘formats’ looked much too different in details. As for acquisition or an explicit solution to Plato’s Problem, while Aspects’s procedure ‘chose’ a grammar with fewer rules (a ‘simpler’ grammar) over one that had more, this is far from a plausible explanation of a child’s managing to acquire any of thousands of natural languages by the same age over the human population, while going through approximately the same stages of development. While a relative selection procedure might be in some way ‘mechanized’, furthermore, somehow accommodating a theory of language to biology still looked daunting: it was particularly hard to understand how the human genome could be expected to contain all the information needed to allow for any of a large number of languages while providing too for a way to choose between them. Even the most optimistic view of language universals at the time (universals require neither acquisition nor choice) would still demand that the genome carry a massive amount of language-specific information, more than any plausible account of evolution could plausibly explain.
Work after Aspects improved the situation considerably. It became more and more apparent that the basic rules/principles and structures of language did not differ that much after all. The phrases of all languages, for example, have heads and complements, and lexical items in all languages seem to “project” phrasal structure in the same way. So apparent differences in phrase structure all but disappear; phrase structure grammar was compressed into a uniform view of lexical “projection.” Movement of elements (“transformations,” displacement) seemed to become far more tractable; a single rule: “move anything anywhere” was proposed, a rule – it was supposed – that would be constrained by a few other factors. Different languages came to look less and less different. Unsurprisingly, then, the complexion of the dominant explanatory issue, Plato’s Problem, changed. Theoretical issues remained concerning where the structures of sentences came from: “projection” replaces multiple phrase structure rules but why is there such an operation, and where did it come from? More progress was made on that front with the introduction of the minimalist program in the early 1990s, to the extent that – oversimplifying and ignoring technical disputes – very recently it has come to seem as if perhaps the sole ‘operation’ (rule, principle) needed to explain both basic structure and movement is what Chomsky and several others call “Merge.” Oversimplifying again, Merge is an operation rather like concatenation – putting items or elements (lexical items) together and creating a new item. More carefully: with lexical items x and y, merging forms the set {x, y}. Something like that is surely needed for there to be language at all, for all languages ‘compose’ – they make complexes called “sentences” out of “words.”
I oversimplified twice to exhibit great
improvements in formal simplicity, to the extent that the number of principles needed to provide an account of how any natural language composes sentences out of ‘words’ might even be reduced to one. My simplifications left out, however – and presupposed – the contribution of an innovation in Chomsky’s grammars of the early 1980s, parameters. Parameters allow for structural differences between languages – among other things, the fact that Italian permits sentences lacking (explicit) subjects, while English and French do not. When first introduced – and this may ultimately be correct, at least in part – parameters were understood as options within universal rules or principles (hence the terminology of a “principles and parameters” framework for the study of grammar). These parametric options provide for structural and sound variations between languages – perhaps differences in meanings too, although it is much less clear that there are such differences. They localize the structural differences allowed for within natural languages, to the extent that – as Chomsky put it (see Chomsky 1988a) – by listing a specific set of options, one can ‘deduce’ Hungarian as opposed to Swahili. In addition to providing a compact and elegant way to describe linguistic differences (ignoring, of course, lexical items), parameters offer other advantages. First, they offer an intuitive way to solve Plato’s Problem; they offer a way to conceive of how language acquisition – lexical or word acquisition aside – could be nothing more than the setting of a few parameters. And second, because they allow for improvements in descriptive adequacy and come close to solving Plato’s Problem by offering what is virtually a selection procedure rather than a relative ‘evaluation’ procedure, they allow the linguist to begin to address other explanatory issues. Until the 1980s and parameters, it looked as though it would be very difficult to offer in a theory of language a descriptively adequate theory of language that could also solve the acquisition problem. Clearly different languages seemed to require very different principles and rules, and a solution to Plato’s Problem seemed to require uniformity and simplicity. If linguistic difference can be localized in a few ‘switches’ and these can be easily set with minimal data; and if there are very few universal principles, perhaps only Merge, the language-specific ‘information’ the human genome must carry can be pared down considerably, and the task of accommodating a theory of language to biology now comes to look a lot more manageable. For assuming a theory of UG is a theory of the language-specific information in the genome, because a theory of UG seems a lot simpler than it had for a long time appeared it would have to be, it looks as though the amount of information concerning UG the genome needs to carry is much smaller than originally thought, perhaps Merge alone. (I ignore concepts, sounds, and lexicon here.) Accommodation to biology looks easier. And perhaps one can even begin to explain how language came to be introduced into the human species by some sort of evolutionary procedure.
