Of Minds and Language (32 page)

I call this criticism unimaginative because I think there is a fairly simple answer to it, which starts by making a familiar, but apparently still not understood, distinction between competence and performance. Again, one thing is to have a thought, and a different one is to be able to share it. In our case, you want to ask how, in particular, a recursive thought process is also sharable. If it were not, we would find ourselves in the somewhat Kafkaesque situation of being, perhaps, truly smart – but solipsistic as well. For all we know, in large part this
is what happens to other animals, and perhaps it did too in our evolutionary lineage until relatively recently. Recursive thoughts, perhaps sharing them systematically, not so obvious. Note in particular that to have a thought that is as complex as a sentence incorporating recursion, what the individual needs to know is that one X (any structure) is different from another X of the same type. That is what gives you the recursion. Observe this concretely, as in (5):

You deal with one X at the top, and another X below, inside, and then if this structure makes it as a thought, you can have recursion. But you absolutely must keep the Xs apart, and moreover somehow know that both are the same types of entity. You need two different tokens of the same syntactic type. If you could not make that distinction for some reason, say because you lacked the computational resources for it, then you would not have the recursive structure, period.

Now, one could argue that the mere generation of the various thoughts, in the thought process in time (however that is done in an actual mental computation by the animals that we are studying), actually gives you different tokenizations of X, probably in a relatively trivial sense if the generative devices are as complex as we are implying, technically a push-down automaton or PDA.
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Plainly, if you, a PDA, are generating one X plus another X within the confines of the first, well, they must be different Xs – you are thinking them differently in the thought process. Ah, but if you want to show me your various uses of X, somehow we must share a way of determining that one X is not the same as the other X. There we may have a problem.

You may think that sheer ordering in speech, for example, does the trick, that ordering separates each token from the next – but not so fast. We have to be careful here, because of Higginbotham's “compression” problem: a unidimensional system like speech is just too simplistic to express the articulated phrasal structure that I think with, including crucially its recursive structure. To illustrate this very simply, as my speech reaches you, you may hear one X, and then
another X – let's grant that much. But how do you know that the next X is really a part of the previous one, and not just another dangling X out there? In other words, given an object to parse like (6a) (a sequence of symbols we hear), how do we know whether to assign it the structure in (6b) or the one in (6c)?

In the latter instance, you would not find yourself in a truly recursive process. At best it would be an instance of a much simpler form of complexity, an
iteration
.
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All iterations can be modeled as recursions, but you can prove that not all recursions can be modeled as iterations. Intuitively, since all you are hearing is a sequence of symbols, after they have been compressed into speech, no matter how complex a phrasal array they may have been within my own brain, you just have no way to decide whether to reconstruct the flat sequence into another, well, flat sequence (6c), or whether to somehow get ahead of the evidence and come up with a more elaborate representation that may actually correspond to what I intended (6b). Too much information is lost in the compression.

This is all to say that, if you set aside telepathy, not only do you need to ground your own Xs within a structure in relevant phrasal contexts, so that you get your own recursion off the ground;
you need to share that with me
also, if I am to reconstruct your private thought process. Without that, we won't reliably share our thoughts, we won't come up with a real lexicon of stored idiosyncrasies to tell each other things, we won't have a very rich culture, and so on and so forth. Kafka had it right, although perhaps his Gregor Samsa would have been any old roach if we grant insects the powers that Gallistel argues for!

Now, as far as I can tell, there is no way to solve Higginbotham's compression problem in full generality, particularly if the information loss is as dramatic as one literally going from many dimensions to one. That said, evolution may have found ways to cut the complexity down; perhaps not foolproof ways, but nonetheless effective enough to take us out of entire solipsism or total guesswork. A nice trick in this regard would be to come up with (sorry for the neologism) “tokenizers” of some sort, for the language system, that is. Again, a grammar can be very complex, entirely useful as a thought mechanism, yet not
effectively communicable if you just have this “unstructured soup” as it were, as it comes out in speech or other forms of expression that rely on motor constraints. That “unstructured soup,” ordered as your thought processes, is a necessary condition for public emergence of language in some organized way, but it is simply not sufficient to succeed in sharing it. You need something else, and this is what I am calling a “tokenizer” for lack of a better term.

Whatever these gizmos turn out to be, they had better come up with a way of somehow fixing various Xs as reliable other instances of themselves, in the sense of true recursion. Moreover these devices have to anchor the structure parsed in speech as not just “another one of those,” but indeed as somehow contained within. If such a nifty device can be evolved by a group of very smart creatures, then they may be on their way to reliably sharing their thoughts. From this perspective, proto-language may not have been usably recursive, no matter how recursive the thought process that sustained it was. But surely language as we understand it is not just capable of sustaining recursive thought, but also of more or less successfully
transmitting
such intricate thoughts. All right, not perfectly (effective use breaks down in garden-path situations, center-embedding, ternary branching, and I am sure much more), but enough to have managed to allow conferences like this one. And the issue is, it seems to me, what that extra step, those tokenizers, bring to the picture.

To make a very long story short (Uriagereka 2008:
Chapter 8
), I will simply give you an instance of what I think could have been one effective tokenizer, and this is how I come back to Case – so that you can see how a Case system would actually constitute a formal tokenizer. The story is based on what, over the years, I have called a viral theory of morphology. By that I mean, metaphorically at this point, that you introduce in a syntactic derivation an element that is actually “extraneous” to it, and crucially uninterpretable to the system. What for? Well, to eliminate it in the course of the derivation. How? That is an interesting issue. In short, linguists still do not understand this in any detail, but we have found that uninterpretable morphology, the sort Case is a prime example of, gets literally excised from the computation – not surprisingly if it has no interpretation – by way of a transformational procedure.

Actually, it is at places like this that we have convinced ourselves of Chomsky's initial insight that context-free grammars, and thus the corresponding PDA automata that execute them, are not enough to carry a syntactic computation. You also need context-sensitive dependencies, no matter how limited they turn out to be.
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For those you plainly need a different automaton; the PDA won't do,
so call it a PDA+. The point is this: you observe, empirically, that the language faculty is forced into these PDA + resources precisely
when Case features are involved
. You don't just eliminate them, in other words. You go through the trouble of invoking complex agreement relations for the task, which is what forces the system into this literally higher-order PDA + computation.

In that I think the analogy with the virus is quite useful. When your organism detects one of those, you go into an internal chaos to excise it, as a result of which drastic warpings and foldings happen within your cells. In my view, this is a way to rationally account for the presence of this sort of morphology, which has very serious consequences for syntactic structuring. It is not just a little noise in the system; it is, rather, a huge issue, a virus, that the system must detect and immediately eliminate. And crucially for my purposes now, as a result of the process, new syntactic structures (literally warped phrase-structures involving new, long-distance, connections) are possible.

So anyway, as a result of immediately killing the virus, the phrase-marker is now warped in a characteristic shape that used to be called a chain, and nowadays goes by the name of a “remerged” structure, and a variety of other names to express the discontinuity of the new dependency thus formed. (It is not important what we call it though; the important issue is the discontinuous dependency.) The Case feature may be gone, thank goodness, but the aftermath is fascinating: a new phrasal dependency is now reliably created, indeed an effective way of anchoring, regardless of its meaning, a given structure X to whatever the domain was where the Case virus was excised.

Remember the mother Case, the father Case, and the child Cases? By thinking of them as viral elements that the system must eliminate immediately at given contexts, we have anchored the element X that eliminates the offending, uninterpretable, stuff
precisely to the context of the elimination
. If this is done in systematic terms within a derivation (mother Case goes first, father Case goes last, child Case is the default), then we have come up with a useful way of relating X to given phrasal contexts, and thus of tokenizing this X (say at father Case) from that X (say at mother Case), and so on.

Now, here is a crucial plus: these Case features are morphemes, not phrases. They do not need, in themselves, any fancy automata to carry their nuances – they are stupid features. Very stupid features, with absolutely no interpretation, which is what sets the entire catastrophe in motion! In other words, these things are fully parseable even at the boring level of speech, which we are granting even tamarins (at any rate, some equivalent motor control). So what did tamarins lack – or more seriously, apes or closer hominids? If we are on the right track here, probably either the resources to come up with the elimination
of this Case virus, or perhaps the very virus that started it all. Be that as it may, this, I think, models a tokenizer of just the sort we were after.

I just wanted to give you a flavor of what role Case may be playing within a system where it appears to make little sense. At the level of the system itself, it is uninterpretable, but perhaps it can be rationally accounted for in some version of the story I told. Seen this way, Case – and more generally uninterpretable morphology – may have been a sort of viral element that for some reason entered a system it was not meant to be a part of. In normal circumstances, that could have been either devastating for the system – a virus of the sort our computers often get – or perhaps just a glitch that the system did not even bother to deal with. But matters seem to have been considerably more intriguing where the language faculty is concerned.

It would appear that the system deployed its full forces to eliminate the intruder, in the process emerging with new structures that, perhaps, would not have emerged otherwise. It is a fascinating possibility, it seems to me, and Massimo Piattelli-Palmarini and I have suggested that it recalls the role of transposon activity within genomes.
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Of course, that too is a metaphor, although it emphasizes the viral connection.

It has become clear that large parts of genomes (including half of ours) have their origin in viral insertions and other “horizontal” transmissions that do not originate in the standard way we are taught in high school. Up to recently, the role of this nucleic material was thought to be irrelevant, hence terms like “junk DNA” applied to it. Well, it turns out that we have only scratched the surface, and in fact entire systems, like of all things the adaptive immune system, may have originated that way (see Agrawal et al. 1998, Hiom et al. 1998).
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This scenario is very curious from the perspective of how the language faculty may have evolved. Viruses are species-specific, tissue-specific, and needless to say they transmit very rapidly, infecting entire populations.