When is the logically impossible possible?

Child's Play has posted the latest in a series of provoking posts on language learning. There's much to recommend the post, and it's one of the better defenses of statistical approaches to language learning around on the Net. It would benefit from some corrections, though, and into the gap I humbly step...


The post sets up a classic dichotomy:

Does language “emerge” full-blown in children, guided by a hierarchy of inbuilt grammatical rules for sentence formation and comprehension? Or is language better described as a learned system of conventions — one that is grounded in statistical regularities that give the appearance of a rule-like architecture, but which belie a far more nuanced and intricate structure?

It's probably obvious from the wording which one they favor. It's also less obviously a false dichotomy. There probably was a very strong version of Nativism that at one point looked like their description of Option #1, but very little Nativist theory I've read from the last few decades looks anything like that. Syntactic Bootstrapping and Syntactic Bootstrapping are both much more nuanced (and interesting) theories.


Some Cheek!


Here's where the post gets cheeky: 

For over half a century now, many scientists have believed that the second of these possibilities is a non starter. Why? No one’s quite sure — but it might be because Chomsky told them it was impossible.

Wow? You mean nobody really thought it through? That seems to be what Child's Play thinks, but it's a misrepresentation of history. There are a lot of very good reasons to favor Nativist positions (that is, ones with a great deal of built-in structure). As Child's Play discuss -- to their credit -- any language admits an infinite number of grammatical sentences, so any finite grammar will fail (they treat this as a straw-man argument, but I think historically that was once a serious theory). There are a number of other deep learning problems that face Empiricist theories (Pinker has an excellent paper on the subject from around 1980). There are deep regularities across languages -- such as linking rules -- that are crazy coincidences or reflect innate structure. 


The big one, from my standpoint, is that any reasonable theory of language is going to have to have, in the adult state, a great deal of structure. That is, one wants to know why "John threw the ball AT Sally" means something different from "John threw the ball TO Sally." Or why "John gave Mary the book" and "John gave the book to Mary" mean subtly different things (if you don't see that, try substituting "the border" with "Mary"). A great deal of meaning is tied up in structure, and representing structure as statistical co-occurrences doesn't obviously do the job. 


Unlike Child's Play, I'm not going to discount any possibility of the opposing theories to get the job done (though I'm pretty sure they can't). I'm simply pointing out that Nativism didn't emerge from a sustained period of collective mental alienation.


Logically Inconsistent


Here we get to the real impetus for this response, which is this extremely odd section towards the end:

We only get to this absurdist conclusion because Miller & Chomsky’s argument mistakes philosophical logic for science (which is, of course, exactly what intelligent design does).  So what’s the difference between philosophical logic and science? Here’s the answer, in Einstein’s words, “No amount of experimentation can ever prove me right; a single experiment can prove me wrong.”

In context, this means something like "Just because our theories have been shown to be logically impossible doesn't mean they are impossible." I've seen similar arguments before, and all I can say each time is:


Huh?


That is, they clearly understand logic quite differently from me. If something is logically impossible, it is impossible. 2 + 2 = 100 is logically impossible, and no amount of experimenting is going to prove otherwise. The only way a logical proof can be wrong is if (a) your assumptions were wrong, or (b) your reasoning was faulty. For instance, the above math problem is actually correct if the answer is written in base 2. 


In general, one usually runs across this type of argument when there is a logical argument against a researcher's pet theory, and said researcher can't find a flaw with the argument. They simply say, "I'm taking a logic holiday." I'd understand saying, "I'm not sure what the flaw in this argument is, though I'm pretty sure there is one." It wouldn't be convincing (or worth publishing), but I can see that. Simply saying, "I've decided not to believe in logic because I don't like what it's telling me" is quite another thing.