Re: “Is the Battle Almost Over?“
Before consulting Ernst Moerk for “solid empirical evidence against the validity of the poverty of the stimulus argument,” please first make sure you know what the poverty of the stimulus means:
According to UG theorists, all human (linguistic) utterances, actual and potential, can be divided into two kinds: those that we (all) judge as grammatically well-formed, and those that we (all) judge as ill-formed.
From the ill-formed ones, we can eliminate all those that are ill-formed merely because of the arbitrary conventions of man-made grammars (“I ain’t got none” — “Between you and I”, etc.).
That still leaves all the ill-formed utterances for which we don’t really know why we perceive them as ill-formed, but we do.
Chomsky set out to explain the implicit rules underlying the difference between those ill-formed utterances (there is an infinity of them) and the ones (likewise infinite) that we perceive as well-formed (or just ill-formed because they violate conventions we have learned and agreed to).
These universally ill-formed utterances — let us call them “starred utterances” because of the convention of preceding them by an asterisk (*) to distinguish them from the well-formed (unstarred) utterances — turn out to be governed by a highly abstract set of underlying rules. These are the rules of universal grammar (UG), because they turn out also to be universal across all languages (which differ only in their [learned] parameter-settings for these rules).
Now before we even get to the poverty of the stimulus, there are those who deny the validity or the universality of our perceptions of grammaticality. They may or may not be right. But if they are right, then the problem of the poverty of the stimulus does not even come up, for it means that UG theorists are looking for rules underlying distinctions that don’t really exist.
So in formulating the problem of the poverty of the stimulus, we will assume that these objections are invalid, that grammatical judgments are indeed reliable, valid, and universal, and that the rules to explain them are not arbitrary but explain a genuine cognitive distinction.
Well, it turns out that the rules that will generate and recognize all and only the unstarred utterances, and recognize and reject the starred ones, are so complicated and abstract that they cannot be learned by the child (or by any inductive learning mechanism) on the basis of the utterances that the child actually hears — or produces, or gets corrective feedback on — during its (brief) language learning period. That is the poverty of the stimulus (POS).
Here too there is a lot of misunderstanding to get out of the way: As already noted, we are not talking here about hearing, producing and getting corrected for conventional grammatical errors. There’s plenty of inductive data available to the child for learning those. We are talking about hearing, producing or getting corrected for violations of UG: utterances that do not conform to the rules that linguists (through laborious decades of collective, cumulative induction — very unlike what the child does in its few language learning years) have discovered, through trial and error, to be the rules underlying UG.
The methodology that linguists use, across the decades, to infer the rules of UG is to hypothesize that something is a rule of UG, and then test it to see whether it produces starred utterances. If it does, it is rejected. This is exactly what the child never does, because it neither hears nor produces (hence also never gets corrected) on starred utterances (except a very few, by chance). There are an infinity of starred and unstarred utterances, and many complex rules. The rules can be learned, but not by the child, because it lacks this crucial positive vs. negative evidence: plenty of positive evidence, but next to no negative evidence.
It is as if you had to learn what a “laylek” was (and, of course, what a laylek wasn’t), and I told you that I’m a laylek, you’re a laylek, things are layleks, ideas are layleks — in fact everything you ever see, hear, taste, smell or think is a laylek. So what’s a laylek? You can’t say, because you haven’t got any examples of what is not a laylek. Hence you have no basis for telling them apart.
That is the poverty of the stimulus.
But before you start coming up with hypothetical counterexamples in principle, remember that we are talking about UG in particular, not just some hypothetical something. So the counterexamples to POS have to be in the form of actual productions by children (and corrections by adults) that are enough to serve as the database for inferring all the actual rules of UG to date (or enough of them to show that it works). It’s not enough to do it for one or a few isolated cases.
The reason no one has done this successfully, is that those who try to show the incorrectness of POS either (1) reject UG to begin with (e.g., by rejecting the reliability of grammaticality judgments) (in which case they are not really addressing the POS problem, but simply rejecting a branch of empirical linguistics out of hand) — or they (2) try to show the incorrectness of POS without actually having mastered what the rules of UG actually are (according to its current formulation). Hence they are not showing that the inductive database is not really impoverished for UG, but merely looking at a few isolated special cases, with no evidence that more of the same would scale up to doing the whole job, namely, enabling the child to learn the rules of UG from positive and negative evidence.
A parting word about “nativism”: What makes the special case of UG so hard is not the fact that the POS entails that UG has to be inborn, because the child’s database is far too weak to serve as a basis for learning it. What makes it so hard is that — unlike with other inborn traits, whether structural or behavioural — the usual explanation for the origin of inborn traits, namely, Darwinian evolution, does not look to be plausible in the special case of UG.
For exactly the same thing that makes the rules of UG unlearnable on the basis of the child’s database — but learnable (painfully and slowly) on the basis of the collective, cumulative database of generations of UG linguists — also makes it just as implausible that UG was “learned” via the usual trial-and-error process of biological evolution either. This is for reasons partly based, again, on POS — but partly also on the fact that no one has yet shown that the rules of UG can be either learned or evolved consecutively, by trial and error, unguided by already inborn UG perceptions, but guided instead by the adaptive advantages of unstarred utterances over starred ones!
For, as far as can be seen so far, unstarred utterances do not have any evolutionary advantages over starred ones (except if you already have UG). Logical (but artificial) alternatives with the same expressive power as UG-governed natural languages are possible. UG is not a matter of logical necessity for the expressive power of language. But it seems it just happens to be there.
That — and not something else, that would simply amount to changing the subject and begging the question — is the problem of the poverty of the stimulus. And that is why UG “nativism” is such a particular puzzle (and hence such a hard problem, evolutionarily).
The only avenues for hope, as far as I can see, are either if it turns out that grammar cannot be done autonomously from form alone, without recourse to meaning (“autonomy of syntax”), and hence that UG rules turn out to be epiphenomena, superfluous for distinguishing unstarred from starred utterances, because the distinction is somehow guided by meaning rather than just formal syntactic structure. (But if this is to turn out to be true, a lot of work remains to be done to show why and how it is true.)
The other avenue would be to prove that UG is in fact a logically necessary property of any symbol system with the expressive power of natural language. (From what I understand of Chomsky’s position on this, he does not go this far. He does indeed think that UG-compliant language is the only possible way for us to think, but he does not give a proof, nor does he indicate that he believes that it is a matter of logical necessity, hence in principle provable.)
See: http://bit.ly/Chomsky-UG-POS
[JanetK asked: “How can POS prove that UG is necessary, if you have to accept UG in order to have POS.”]
POS does not prove UG necessary. POS proves UG is unlearnable by the child (given the child’s actual database).
If you want to prove UG is fiction, explain how children and adults are capable of producing all and only the UG-compliant utterances, and rejecting the rest as ungrammatical.
None of this can be done at this level of vagueness. Most critics of UG haven’t the faintest idea of what the rules of UG are, nor what the capacity is that those rules were adduced to explain. But that does not stop them from expressing objections to UG with vehemence and conviction. I have always found that extremely puzzling.
I am not a linguist, technically capable of saying, one way or the other. But I have become quite adept at spotting question-begging and non sequiturs across the years, on the part of others who are as ignorant of the technical specifics of UG as I am, yet think they have some sort of refutation…
The question of “necessity” only concerned whether or not UG was a logical necessity in order to have the expressive power of natural language. (It could merely be necessary as a matter of historical/evolutionary fact, rather than logical necessity.) Chomsky thinks UG is necessary in order to think, but I don’t think he means logical necessity.
Yes, the origin of UG is a problem for evolutionary explanation, but it is not clear that it is part of the empirical burden of syntacticians either to explain the evolutionary origins of the rules they discover, or to restrict their research to rules that are either learnable or have a ready evolutionary explanation.
This does not mean that I do not remain perplexed by the evolutionary origins of UG…
The Power (and Poverty) of Words
Based on the latest posting of Edmund Blair Bolles on this topic thread, I think this will be my last contribution, because I am beginning to suspect that Edmund is not really serious about trying to address the problem of UG and POS.
The examples Edmund gives in his posting — examples of uses of the word “run” — have nothing at all to do with UG. They are examples of the constraints of conventional grammar, which are learnable, and learned.
As I said, across the decades, many, many would-be critics of Chomsky and UG have aired their opinions without ever confronting, let alone understanding the actual empirical evidence (in all the systematic starred and unstarred utterances that every human being can produce and distinguish, the ones that are actually at issue — not arbitrary, isolated ones of our own choosing.)
The utterly pointless example of “run” is a case in point.
Nor is the question about whether the rules are “in the stimulus,” to be “perceived.” The question is whether the examples of utterances that the child hears and says, and the corrections that the child receives, are sufficient for the child to learn the rules of UG from them — as they are indeed sufficient, for example, in the case of learning the rules of chess, or of arithmetic.
To show that the Brown database is sufficient for this, you have to actually show how those data are enough so that the child can figure out from them all the rules that it has been taking teams of linguists decades to begin to piece together.
The problem of POS is that the child’s database (e.g., the data in the Brown corpus) is not sufficient. There is nowhere near enough there for the child — or any learning system — to induce the rules of UG on the basis of those data alone. (The rules of UG — not a layman’s pet proxy for that complex set of rules on which linguists are still working. Otherwise I could state with confidence that, say, both Goedel’s theorem and Quantum Mechanics are false, based on my own pet examples.)
(I expressed no objection whatsoever that Edmund did not review my paper. I just said that he had missed the point about UG. And his is still missing it. I have great faith in words for bridging any and every conceptual gap — but for there to be a way, there has to be a will!)