WHAT IS COMPUTATIONALIST BIOLINGUISTICS ABOUT?
WHAT DO COMPUTATIONALIST BIOLINGUISTS DO ?
WHAT ABOUT YOUR FRIENDS, COMPUTATIONAL LINGUISTS?
[NOTE: The contents herein reflect my understanding of the issues, and are prone to change with them. Keep a pinch of salt handy!]
Primarily, we are interested in understanding the nitty-gritty of the Biology underpinning Language. Notice the use of the singular form? That is the first crucial distinctions that we make -- between Language as a biological ability and a natural phenomena, and languages like English, Swahili, Telegu etc., and the so-called grammars that describe their various properties. This latter traditional sense of languages is of little interest to us, although it is not quite irrelevant. The focus, however, is on the organism, homo sapien, its brain which enables a phenomena that is not observed anywhere else, and causally explaining:
I. What do we mean when we say 'Language'?
When we study human language, we are approaching what some might call the "human essence," the distinctive qualities of mind that are, so far as we know, unique to man.
-- Noam Chomsky, Language and Mind --
II. What is so interesting about Language? Even babies can manage... right?
The child, placed in a linguistic community, is presented with a set of sentences that is limited and often imperfect, fragmented, and so on. In spite of this, in a very short time he succeeds in "constructing," in internalizing the grammar of his language, developing knowledge that is very complex, ..
-- Noam Chomsky, Language and Responsibility --
Sparsity of Input & Poverty of Stimulus
(courtesy: Prof. Charles Yang)
So the obvious hypothesis is that our language is the result of the unfolding of a genetically determined program.
-- Noam Chomsky, KBS TV Kyoto, Japan --
III . Whatever is 'interesting', if anything is, why is it interesting in that particular way?
“From the point of view that I adopt here, the fundamental empirical problem of linguistics is to explain how a person can acquire knowledge of language”
-- Noam Chomsky (Chomsky, 1973/1977; 81) --
The above quote introduces, in very simple words, the notion of explanatory adequacy. It is an interesting notion, and one that is at once a hallmark of true Natural Science and the one central point of denial around which much of the pseudoscientific posturisms that dominate cognitive science(s) in general revolve. It does not require a rocket scientist to understand that describing every aspect of a bluejay, for instance, tells one nothing at all about what sort of creature the bluejay is! Nick Tinbergen received a Nobel Prize for explaining in much detail how to provide biological explanations of similar matter, and that was almost a century ago. Indeed, having witnessed such absurdities as is readily observable in the many quasi-scientific and pseudo-scientific hoopla that crowd the backyard of the confused discipline that is cognitive science -- ranging from the so called "eliminative connectionism” to the mainstream standard "generative""phonology" (neither generative in any meaningful sense, nor phonological in its subject matter by any stretch of the imagination) -- the mayhem caused by systematic replacement of explanation with description has become a source of recurring nightmare for me. As my old friend, the late Jerry Fodor once remarked, "what strange inversions of reasoning" (two examples, in my humble opinion, involve the so-called implicational laws of palatalization and “learning” phonology with “substantive bias” — the former merely articulatory inertia that does not belong in “phonology” (cf. Reiss, 2003, 2007) and the latter evidence of grammar re-interpreted in the opposite direction).
Returning to the topic at hand, i.e. explanation vs. description, in his seminal work Aspects of the Theory of Syntax (1965), Noam Chomsky introduces a hierarchy of levels of adequacy for evaluating grammars (theories of specific languages) and metagrammars (theories of grammars).
These levels constitute a taxonomy of theories (a grammar of a natural language being an example of such a theory) according to potency. This taxonomy might be extended to scientific theories in general, and from there even stretched into the realm of the aesthetics of art. This present article's use of the phrase as a terminus technicus should not be confused with its everyday language uses.
The theory achieves an exhaustive and discrete enumeration of the data points.
There is a pigeonhole for each observation.
The theory formally specifies rules accounting for all observed arrangements of the data.
The rules produce all and only the well-formed constructs (relations) of the protocol space.
...the grammar gives a correct account of the linguistic intuition of the native speaker, and specifies the observed data (in particular) in terms of significant generalizations that express underlying regularities in the language.
The theory provides a principled choice between competing descriptions.
It deals with the uttermost underlying structure.
It has predictive power.
A linguistic theory that aims for explanatory adequacy is concerned with the internal structure of the device [i.e. grammar]; that is, it aims to provide a principled basis, independent of any particular language, for the selection of the descriptively adequate grammar of each language.
Theories which do not achieve the third level of adequacy are said to "account for the observations", rather than to "explain the observations."
The second and third levels include the assumption of Ockhamist parsimony. This is related to the Minimalist requirement, which is elaborated as a corollary of the levels, but which is actually employed as an axiom.
But what does all of these mean for us?
Noam Chomsky (Chomsky, 1973) in his foundational paper Conditions on Transformation (Chomsky, 1973) highlights the importance of acquisition of languages by children as a phenomena by linking it to the technical specification of the intuitive notion of explanatory adequacy. Any analysis of linguistic phenomena is said to meet the requirements of explanatory adequacy if and only if it goes beyond mere description of WHAT the child is doing and is able to explain causally HOW the child is doing so, and WHY said process takes a particular trajectory of progress as opposed to several possible ‘others’. A central puzzle identified by Chomsky, and one that has defined linguistic research for the last half a century, concerns the previously mentioned notion of poverty of stimulus which implicates fatally the erroneous worldview that adult knowledge can be achieved by inductively, and through analogy, organizing experiences into a tabula which is intially rasa. Chomsky rightly points out a mere description of language typology is prone to overfit UG to specific languages, unless we are mindful of the three factors in Language design (Chomsky, 2005) – Language, in the abstract and universal sense, is a biological ability (like binocular vision), but it’s externalization in the form of speech is contingent on other systems and processes not unique to the cognitive domain of Language. Thus speech, the mind-external linear form of language, manifests properties other than hierarchical linguistic structures, and attempts at back-calculating the cognitive mind from linear speech forms results in the theory of mental Grammar being burdened with effects of which it is not the cause. The task of the computationalist biolinguist, then, is three-fold – first, she must identify and take seriously the formalisms about Language structure detailed by the past fifty years of Generative Grammar, then she must reject the notion of linguistic reality (of structures and dependencies) are real in some ‘other’ sense than the one of ‘psychological reality’(they are all psychologically real, because they are computed in real-time), and finally she must identify possible circuits in the brain (also real in a real sense, or really real!) and then solve the problem/answer the question of how aforementioned real formalisms are implemented in real-time by the biological reality of our neural architectures. It is important to note, however, as Poeppel and Embick do in their seminal works together, that in so doing one must avoid the pitfall of trying to reduce processes to processors.