For the last ten years or so, Chomsky has been claiming increasingly often that the discrete bifurcation of expressions into “grammatical” and “ungrammatical” is incorrect. I think he is wrong, or at least that these claims are without any current basis. But before explaining why, it’s important to set some parameters of the discussion.
First, we have to fix what we mean by expressions. If we mean strings, or even a given token of phonation, then I have no quarrel with this. Taking strings as the object of study in linguistics is, to quote Indiana Jones, “digging in the wrong place.” A grammatical constraint, like the Complex NP Constraint (CNPC) for example, can reduce the number of meanings associated with a given string from one to zero, as in (1):
(1) * Which dish do you know the guy who brought?
But the same constraint can reduce the number of meanings associated with a different string from two to one, as in (2) (which can be interpreted as a question about reasons for knowing, but not as a question about reasons for bringing):
(2) Why do you know the guy who brought this dish?
A preoccupation with strings as the object of study necessarily misses the point of grammatical constraints, since it artificially affords (1) (which has zero remaining meanings) different status than (2) (which has a non-zero number of remaining meanings).
So, if Chomsky’s point is, “You can’t bifurcate the set of strings into grammatical and ungrammatical,” then there is no disagreement here. But that doesn’t have anything to do with the notion of grammaticality as such. It has to do with misapprehending the object of study. Language does not generate “strings”; it generates structures. Or, if you prefer (though I do not): form-meaning pairings.
But this is not Chomsky’s point, I don’t think. He seems to be saying that structures (or form-meaning pairings) cannot be bifurcated into grammatical and ungrammatical, either. As best I can tell, he has offered two arguments for this view over the years – and both of them are unsound.
The first putative argument is that utterances simply cannot be bifurcated into acceptable and unacceptable; there is, instead, a range of degrees of acceptability. Therefore, the argument goes, a theory of grammar that delivers a binary verdict (either “grammatical” or “ungrammatical”) is inadequate. The flaw here is in reasoning from the gradience of a behavioral measure – in this case, acceptability – to the gradience of a computational predicate (grammaticality). As Armstrong, Gleitman & Gleitman (1983) showed,1Armstrong, Sharon Lee, Lila R. Gleitman & Henry Gleitman. 1983. What some concepts might not be. Cognition 13:263–308, DOI: 10.1016/0010-0277(83)90012-4. you can get gradient responses from people to prompts like “How even/odd is this number?” That doesn’t mean that even or odd are gradient predicates. The gradience of acceptability (as a behavioral measure) doesn’t mean that grammaticality (as a computational predicate) is gradient, either.2I must say, I find it quite baffling that this basic point is lost on so many in cognitive science, even among certain self-identifying linguists. I remember attending a keynote by Tom Wasow at the 2015 DGfS – so, 32 years after Armstrong, Gleitman & Gleitman’s paper was published – in which more or less the entire talk rested on this error of inferring gradience in the grammar from gradience in the behavioral measure of acceptability.
The second putative argument is related to the first, but it is logically separable. The argument is that language users can assign an interpretation even to purportedly “ungrammatical” expressions. The examples that Chomsky tends to give here, quite tellingly I think, tend to involve s-selectional violations that can be used as idioms, metaphors, and/or conventionalized sayings, like Misery loves company. But nobody in their right mind thinks s-selection is a syntactic phenomenon.3Chomsky has a long history of conflating s-selection with syntax. You can see the seeds of this in his work in the ’50s and ’60s, where purely semantic features like [±abstract] (distinguishing abstract vs. concrete nouns) were projected from terminals. This was an understandable move at the outset of modern syntactic theory. But it is extremely strange to still be clinging to it now. There’s every reason to believe that the grammar generates the structure which pairs the string Misery loves company with the meaning whereby there is an individual denoted by the DP misery that stands in the love relation to an individual denoted by the DP company. That this literal meaning is not (typically) the communicative intent we ascribe to a speaker who has uttered this expression is interesting but, in the grand scheme of things, entirely unremarkable. We also don’t usually interpret Can you pass me the salt? as a polar question seeking information about the addressee’s capabilities. Language use can override the literal meaning associated with an expression; this is not news.
Chomsky might be well served to re-read Syntactic Structures (Chomsky 1957), where (3) was contrasted with (4) (asterisk is mine; see below for discussion):
(3) Colorless green ideas sleep furiously.
(4) * Furiously sleep ideas green colorless.
Given the discussion of s-selection, above, we would want to say that (3) is generated by the grammar, it just happens to have an odd literal meaning, that (at least at the time that this sentence was first brought under discussion) was not associated with any conventionalized meaning. But would we want to say that about (4)?
I’m not suggesting that it is an impossible cognitive task to assign, if forced, an interpretation to (4). But it seems plausible to me that the latter requires considerable cognitive control. This would mean that it is manifestly not the result of the automatic / barely volitional computations that are the object of study in linguistic theory. One can, by exerting conscious effort, assign interpretations to a whole range of things – programming languages, animal noises, etc. etc. That hardly means that the latter interpretations are “generated by the mental grammar” in any relevant sense.
And so, I conclude that Chomsky has yet to present any valid argument against the bifurcation of structures into grammatical(=well-formed) and ungrammatical(=ill-formed). That does not mean that grammatical structures cannot be experienced as quite weird (e.g. (5)). Nor does it mean that, exerting conscious effort, it is impossible to assign some meaning or other to word salad like (4). Nor does it mean that acceptability, as a behavior measure, will not be gradient.
(5) The square root of Milly’s desk drinks humanity. (Chierchia & McConnell-Ginet 2000:46)
Consequently, the theory that takes examples like (6) to be categorically ill-formed (i.e., not generated by the grammar of my idiolect of English) is very much still in business. Yes, it’s possible to assign some meaning to (6) if forced (e.g. the speaker secretly believes that the child is composed of a tiny British committee wrapped in a trenchcoat). But there is no reason to believe the latter process is carried out by the mental grammar (cf. “meaning” in programming languages).
(6) * The child are here.
This leaves open, of course, the possibility that some things traditionally thought of as “ill-formed” turn out to be better characterized as “well-formed but deviant.” In fact, this is precisely what happened in the history of the treatment of examples like (3) and (5): in Aspects (Chomsky 1965), features like [±abstract] (distinguishing abstract nouns from concrete ones) were projected in the syntactic phrase marker, meaning the reduced acceptability of (3) and (5) was a matter handled by the syntax. (See also fn. 3, above.) Later, it was recognized that this treatment just recapitulates something that the semantic component has to do anyway, and so there is no point in duplicating the same mechanism in the syntax. That is progress and it is good; but it bears not one bit on the question of grammaticality as a binary notion.
This post was prompted by a facebook conversation with Halldór Ármann Sigurðsson. The views expressed here are my own.