Chomsky's dumb evolutionary conjecture

So, once again Chomsky’s naivety (nay, ignorance) has been revealed for all the world to see. Just imagine thinking that one could isolate a single factor as key to language facility, restrict it to but a single species and proclaim that it just popped into existence acting as a gateway innovation resulting in complex patterns of cognition and behavior all without the shaping effects of natural selection. Imagine it! The stupidity of endorsing the discredited  “hopeful monster” point of view of language! How naïve! How uninformed! How irresponsible.

But wait. It seems that Chomsky is not the only naïf endorsing such views. It seems that he now has a fellow traveller (no doubt another one of his duped accolytes), a certain guy called Richard Dawkins. Some of you might have heard about him. He has apparently done some work on evolutionary theory (here). Almost certainly not in the same league as those evolutionary luminaries like Hurford, or Lieberman, or Pinker or Jackendoff, or Tomasello, but, I have been told, Dawkins is at least in the first tier of the second rank. Sort of like Francois Jacob, another biologist who has views not unlike Chomsky’s (see here). At any rate, Dawkins has recently come out and endorsed Chomsky’s evolutionary scenario, zeroing in on recursion as the key innovation behind the human leap into language (and subsequently culture) and arguing that this step had to be taken in one bound as there are no conceptually coherent scenario where smaller steps take you to unbounded recursion. Let me elaborate.

Recently, Bob Berwick told me he was reading the second installment of Dawkin’s autobiography (here). In it Dawkins discusses the evolution of language and Chomsky’s musings on the topic. I asked him for the page references so that I could share them with you. Here are some relevant quotes (with some comments).

As I mentioned on page 290, the main qualitative feature that separates human language from all other animal communication is syntax: hierarchical embedment of relative clauses, prepositional clauses etc. The software trick that makes this possible, at least in computer languages and presumably in human language too, is the recursive subroutine.

It looks as though the human brain must possess something equivalent to recursive subroutines, and it’s not totally implausible that such a faculty might have come about in a single mutation, which we should probably call a macro-mutation. (382)

Note the parts that I bolded. Dawkins’s accepts that the key linguistic innovation is recursion, in fact, hierarchical recursion. Moreover, it is not implausible to think that this recursive capacity arose in on go. Why does Dawkin’s think that this is “not implausible”? Here’s what he says:

The reason I am prepared to contemplate macro-mutation in this case is a logical one. Just as you can’t have half a segment, there are no intermediates between a recursive and a non-recursive subroutine. Computer languages either allow recursion or they don’t. There’s no such thing as half-recursion. It’s an all or nothing software trick. And once that trick has been implemented, hierarchically embedded syntax immediately becomes possible and capable of generating indefinitely extended sentences. The macro-mutation seems complex and ‘747-ish’ but it really isn’t. It’s a simple addition – a ‘stretched DC-8 mutation’ – to the software, which abruptly generates huge, runaway complexity as an emergent property. ‘Emergent’: important word, that. (383)

Again, note the bit in bold. This is an important point and, if correctly understood, it undercuts the relevance of those studies that take the existence of finite frames as important linguistic precursors of our kind of competence. So, many have pointed to proposed earlier stages of simple syntactic combination (e.g. NVN structures) as key evolutionary precursors of our full blown recursive mechanisms. Dawkins is pointing out the logical fallacy of this suggestion. There are no steps towards recursion. You either have it or you don’t. Thus, whether or not earlier “finite” stages existed cannot possibly explain how the recursive system arose. There is an unbridgeable logical gap between the two. And that’s an important point for it invalidates virtually all research trying to show that human language is just a simple quantitative extension of our ancestors capacities.

Dawkins continues the above quote with the following, where he asks whether the communicative function of language was a plausible driving force for spreading the novel language change:

If a mutant human was born, suddenly capable of true hierarchical syntax, you might well ask who she could talk to. Wouldn’t she have been awfully lonely? If the hypothetical ‘recursion gene’ was dominant, this would mean that our first mutant individual would express it and so would 50 per cent of her offspring. Was there a First Linguistic Family? Is it significant that Fox P2 actually does happen to be a genetic dominant? On the other hand, it’s hard to imagine how, even if a parent and half her children did share the software apparatus for syntax, they could immediately start using it to communicate. (383)

Like Chomsky, Dawkins does not see how the communicative function of language was a plausible force. He does not speculate, as Chomsky and Jacob have, that the capacity for recursion enhanced cognition in the lucky individual even if there was no plausible communicative benefit. However, just like Chomsky, he does not see how communicative benefits could play any useful role.

Dawkins ends with the following accreditation:

Noam Chomsky is the genius mainly responsible for our understanding of hierarchically nested grammar, as well as other linguistic principles. He believes that human children, unlike the young of any other species, are born with a genetically implanted language-learning apparatus in the brain. The child learns the particular language of her tribe or nation, of course, but it is easy for her to do so because she is simply fleshing out what her brain already ‘knows’ about language, using her inherited language machine.

But Chomsky’s hereditarian position in this one instance makes sense and, more to the point, interesting sense. The origin of language may represent a rare example of the ‘hopeful monster’ theory of evolution. (383-4)

Note one last time the bold stuff. Dawkins finds nothing evolutionarily suspect about Chomsky’s hypothesis. Indeed, it makes “interesting sense.” Might we say that it is a bold conjecture?

Does Dawkin’s endorsement show that Chomsky’s evolutionary conjecture is right? NO!! But Hopefully it will put to rest the idea that it’s some crackpot out in left field idea that anybody who knew anything about evolution would immediately see was ridiculous. It’s not and never has been. Maybe our local evolutionary mavens can stop suggesting otherwise. Or, more modestly, if what Chomsky believes is considered reasonable by Dawkins and Jacob (among other biologists I am quite sure) then maybe that is sufficient to indicate that it is not biologically suspect on its face. In fact, one might go further and note that it is the right kind of proposal; one that isolates a simple property that should it have arisen could be expected to have far reaching evolutionary consequences. So, Chomsky’s proposal might be wrong, but it is a contender, indeed an “interesting” one. And as the movie notes, all anybody really wants is to be a contender.

It never ends, never

Chomsky really brings out the worst in commentators. And to prove this, here is another deeply confused piece from The Economist commenting on the recent Berwick and Chomsky (B&W) book. The gist of the criticism is the following:

The emergence of a single mutation that gives such a big advantage is derided by biologists as a “hopeful monster” theory; most evolution is gradual, operating on many genes, not one. Some ability like Merge may exist, but this does not explain why some words may merge and others don’t, much less why the world’s languages merge so differently.

So, what's wrong with Chomsky's idea is that such a big advantage could not possibly come from such a small change. This would be a "hopeful monster" theory and as we all know, these are false.  How exactly? Here are several ways, some of which B&C could agree with.

Well, one might argue, as Hauser has here that there is more to the evolution of language than merge. Hauser does not deny that Merge is a big deal, but he thinks that getting the rest of the cognitive system up to speed so that it plays nicely with Merge is hardly trivial.  He also thinks that there are changes to the conceptual system that need some explanation (the mystery of words/concepts) that also needs some discussion. I am pretty sure that B&C would agree with this. Their claim is not that given Merge there is nothing else to explain, rather that Merge is linguistically sui generis and that there is no piecemeal account for its emergence. Merge, or the recursive "trick," is an all or nothing affair.

Hauser agrees with this for the same reason that another rather well known evolutionary theorist does. To quote Dawkins from volume 2 of his autobiography:

As I mentioned on page 290, the main qualitative feature that separates human language from all other animal communication is syntax: hierarchical embedment of relative clauses, prepositional clauses etc. The software trick that makes this possible, at least in computer languages and presumably in human language too, is the recursive subroutine.

It looks as though the human brain must possess something equivalent to recursive subroutines, and it’s not totally implausible that such a faculty might have come about in a single mutation, which we should probably call a macro-mutation. (382)

So, maybe "Many scholars find this to be somewhere between insufficient, improbable and preposterous." But it would be nice to hear how they conceive of unbounded hierarchical recursion arising in the species.

Nor are the views expressed in B&C without credence among evolutionary mavens. It seems that some well known scholars do not find the B&C view of Merge absurd. Dawkins, someone who has dabbled in these areas, even gives a reason for why in this case he considers a macro mutation perfectly reasonable:

The reason I am prepared to contemplate macro-mutation in this case is a logical one. Just as you can’t have half a segment, there are no intermediates between a recursive and a non-recursive subroutine. Computer languages either allow recursion or they don’t. There’s no such thing as half-recursion.It’s an all or nothing software trick. And once that trick has been implemented, hierarchically embedded syntax immediately becomes possible and capable of generating indefinitely extended sentences. The macro-mutation seems complex and ‘747-ish’ but it really isn’t. It’s a simple addition – a ‘stretched DC-8 mutation’ – to the software, which abruptly generates huge, runaway complexity as an emergent property. ‘Emergent’: important word, that. (383)

Note why: It's because "there is no such thing as half-recursion." Just so. So, wrt the recursive property characteristic of natural language it's one big jump or nothing. You can't jump the recursive canyon in several steps. And this is what B&C (and Dawkins) are saying. If Johnson (or the "scholars" he has consulted) thinks otherwise , it would be nice to hear his (their) story. Let's see how you get from finite to infinity in small deliberate steps. Note Dawkins observation that the problem is "logical" as "there are no intermediate steps between a recursive and a non-recursive subroutine." If this logical point is right, then Mr Johnson (and his scholars of note) have, as Lucy Ricardo used to say, "have some esplaining to do."

There is a tendency to go after Chomsky without actually presenting his arguments. This is one of those cases. I can see disagreeing with Chomsky's claims and conclusions. I have done so (to my horror) several times. Hauser did it in his brief review of B&C noted above. I can see arguing that an preferred argument doesn't pass muster. What I find remarkable is that gossip can pass as considered argument.

The problem of how language arose in the species is hard, the facts surrounding it are diffuse and the relevant questions worth addressing abstruse. Chomsky has articulated and defended a position in an area where this is a rarity. He has identified a feature of language that seems special to it (unbounded hierarchical structure) and noted that it calls for recursive capacities of a special sort. Moreover, he has noted that logically these capacities are an all or none affair. He might be wrong (though in this case I don't see how) but he has earned the right to be taken seriously. But he isn't. Why not?

It is pretty clear to me that there is an agenda: demonstrate that Chomsky is passed his sell-by date, that his views are batty and out of touch, that he is a crank. And if his scientific views are way out there and not worth serious consideration, then all the more his less technical (i.e. political) views. Is there an agenda? You bet there is! Are you surprised? I'm not. 

Inference to some great provocations

David Berlinsky is editing a newish online magazine Inference that articles in which I have mentioned in several previous posts. The latest issue is full of fun for linguists as there are four articles of immediate relevance. Here’s the link for the issue. Let me say a word or two about the pieces.

The first is an essay by Chomsky that goes over familiar ground regarding the distinctive nature of human linguistic capacity. He observes that this observation has a Cartesian pedigree and that language was recognized as distinctive (all and only humans have it) and wondrous (it was free and capable of expressing unboundedly many thoughts) and demanding of some kind of explanation (it really didn’t fit in well with what was understood to be the causal structure of the physical world) as early as it was noticed.

As Chomsky notes, Cartesians had relatively little of substance to say about the underpinnings of this wondrous capacity, mainly because the 17^th century lacked the mathematical tools for the project. They had no way of describing how it was possible to “make infinite use of finite means” as von Humboldt put it (2). This changed in the 20^th century with Church, Godel, Post and Turing laying the foundations of computation theory. This work “demonstrated how a finite object like the brain could generate an infinite variety of expressions.” And as a result, “[i]t became possible, for the first time, to address part of” the problem that the Cartesians identified (2).

Note the ‘part of’ hedge. As Chomsky emphasizes, the problem the Cartesians identified has two parts. The first, and for them the most important feature, is the distinction between “inclined” vs “impelled” behavior (3). Machines are impelled to act, never “inclined.” Humans, being free agents, are most often “inclined” (though they can be “compelled” as well). Use of language is the poster child for inclined behavior. Cartesians had no good understanding of the mechanics of inclination. As Chomsky observes, more than 300 years later, neither do we. As he puts it, language’s “free creative use remains a mystery,” as does free action in general (e.g. raising one’s hand) (3).

The second part, one that computation theory has given us a modest handle on, is the unbounded nature of the thoughts we can express. This feature very much impressed Galileo and Arnauld & Lancelot and von Humboldt, and it should impress you too! The “infinite variety” of meaningfully distinct expressions characteristic of human language “surpasse[s] all stupendous inventions” (1).  Chomsky has redubbed this feature of language “the Basic Property” (BP). BP refers to a property of the human brain, “the language faculty,” and its capacity to “construct a digitally infinite array of structured expressions” each of which “is semantically interpreted as expressing a thought, and each can be externalized by some sensory modality such as speech” (2).  BP is what GG has been investigating for the last 60 years or so. Quite a lot has been discovered about it (and yes, there is still lots that we don’t know!).

Chomsky emphasizes something that is worth reemphasizing: these facts about language are not news. That humans have linguistic creativity in the two senses above should not really be a matter of dispute. That humans do language like no other animal does should also be uncontroversial. How we do this is a very tough question, only a small part (very small part) of which we have managed to illuminate. It is sad that much debate still circulates around the whether question rather than the how. It is wasted time.

An important theme in Chomsky’s essay turns on how the world looks when we have no idea what’s up. Here is a quote that I believe all good scientifically inclined GGers should have tattooed to themselves (preferably in some discrete place) (3):

When understanding is thin, we expect to see extreme variety and complexity.

Absolutely! Variety and complexity are hallmarks of ignorance. And this is why progress and simplicity go hand in hand. And this is why I have clasped to my heart Dresher’s apposite dictum: There should be only two kinds of papers in linguistics: (i) papers that show that two things that look completely different are roughly the same and (ii) papers that show that two things that are roughly the same are in fact identical. These are the papers that highlight our progressively deeper understanding. Complication is often necessary, but it is progressive just in case it paves the way for greater simplicity.

The unification and simplicity is, thus, a leading indicator of scientific insight. Within linguistics it has a second function. It allows one to start addressing the issue of how FL might have evolved.  Here’s Chomsky:

In the analysis of the Basic Property, we are bound to seek the simplest computational procedure consistent with the data of language. Simplicity is implicit in the basic goals of scientific inquiry. It has long been recognized that only simple theories can attain a rich explanatory depth. “Nature never doth that by many things, which may be done by a few,” Galileo remarked, and this maxim has guided the sciences since their modern origins. It is the task of the scientist to demonstrate this, from the motion of the planets, to an eagle’s flight, to the inner workings of a cell, to the growth of language in the mind of a child. Linguistics seeks the simplest theory for an additional reason: it must face the problem of evolvability. Not a great deal is known about the evolution of modern humans. The few facts that are well established, and others that have recently been coming to light, are rather suggestive. They conform to the conclusion that the language faculty is very simple; it may, perhaps, even be computationally optimal, precisely what is suggested on methodological grounds.

Unless FL is simpler than we have considered it to be up till now (e.g. far simpler than say GBish models make it out to be) then there is little chance that we will be able to explain its etiology. So there are both general methodological grounds for wanting simple theories of FL and linguistic internal reasons for hoping that much of the apparent complexity of FL is just apparent.

Chomsky’s piece proceeds by rehearsing in short form the basic minimalist trope concerning evolvability. First, that we know little about it and that we will likely not know very much about it ever. Second, that FL is a true species property as the Cartesians surmised. Third, that FL has not evolved much since humans separated. Fourth, that FL is a pretty recent biological innovation. The third and fourth points are taken to imply that the Basic Property aspect of FL must be pretty simple in the sense that what we see today pretty well reflects the original evo innovation and so its properties are physically simple in that they have not been shaped by the forces of selection. In other words, what we see in BP is pretty much undistorted by the shaping effects of evolution and so largely reflect the physical constraints that allowed it to emerge.

All of this is by now pretty standard stuff, but Chomsky tells it well here. He goes on to do what any such story requires. He tries to illustrate how a simple system of the kind he envisions will have those features that GG has discovered to be characteristic of FL (e.g. structure dependence, unboundedly many discrete structures capable of supporting semantic interpretation etc.). This second step is what makes MP really interesting. We have a pretty good idea what kinds of things FL concerns itself with. That’s what 60 years of GG research has provided. MP’s goal is to show how to derive these properties from simpler starting points, the simpler the better. The target of explanation (the explanadum) are the “laws” of GB. MP theories are interesting to the degree that they can derive these “laws” from simpler more principled starting points. And, that, Chomsky argues, is what what makes Merge based accounts interesting, they derive features that we have every reason to believe characterize FL.[1]

Two other papers in the issue address these minimalist themes. The first is a review of the recent Berwick & Chomsky (B&C) book Why only us. The second is a review of a book on the origins of symbolic artifacts. Cederic Boeckx (CB) reviews B&C. Ian Tatersall (IT) reviews the second. The reviews are in interesting conflict.

The Boeckx review is quite negative, the heart of the criticism being that asking ‘why only humans have language’ is the wrong question. What makes it wrong? Well, frankly, I am not sure. But I think that the CB review thinks that asking it endorses a form of “exceptional nativism” (7) that fails to recognize “the mosaic character of language,” which, if I get the point, implies eschewing “descent with modification” models of evolution (the gold standard according to CB) in favor of “top-down, all-or-nothing” perspectives that reject comparative cognition models (or any animal models), dismiss cultural transmission as playing any role in explaining “linguistic complexity” and generally take a jaundiced view of any evolutionary accounts of language (7-8). I actually am skeptical regarding any of this.

Before addressing these points, however, it is interesting that IT appears to take the position that CB finds wrong-headed. He thinks that human symbolic capacities are biologically quite distinctive (indeed “unique”) and very much in need of some explanation. Moreover, in contrast to CB, IT thinks it pretty clear that this “symbolic activity” is of “rather recent origin” and that, “as far as can be told, it was only our lineage that achieved symbolic intelligence with all of its (unintended) consequences” (1). If we read “symbolic” here to mean “linguistic” (which I think is a fair reading), it appears that IT is asking for exactly the kind of inquiry that CB thinks misconceived.

That said, let’s return to CB’s worries. The review makes several worthwhile points. IMO, the two most useful are the observation that there is more to language evolution than the emergence of the Basic Property (i.e. Merge and discretely infinite hierarchically structured objects) and that there may be more time available for selection to work its magic than is presupposed.  Let’s consider these points in turn.

I think that many would be happy to agree that though BP is a distinctive property of human language it may not be the only distinctive linguistic property. CB is right to observe that if there are others (sometimes grouped together as FLW vs FLN) then these need to be biologically fixed and that, to date, MP has had little to say about these. One might go further; to date it is not clear that we have identified many properties of FLW at all. Are there any?

One plausible candidate involves those faculties recruited for externalization. It is reasonable to think that once FLN was fixed in the species, that linking its products to the AP interface required some (possibly extensive) distinctive biological retrofitting. Indeed, one might imagine that all of phonology is such a biological kludge and that human phonology has no close biological analogues outside of humans.[2] If this is so, then the question of how much time this retrofitting required and how fast the mechanisms of evolution (e.g. selection) operate is an important one. Indeed, if there was special retrofitting for FLW linguistic properties then these must have all taken place before the time that humans went their separate ways for precisely the reasons that Chomsky likes to (rightly) emphasize: not only can any human acquire the recursive properties of any G, s/he can also acquire the FLW properties of any G (e.g. any phonology, morphology, metrical system etc.).[3] If acquiring any of these requires a special distinctive biology, then this must have been fixed before we went our separate ways or we would expect, contrary to apparent fact, that e.g. some “accents” would be inaccessible to some kids. CB is quite right that it behooves us to start identifying distinctive linguistic properties beyond the Basic Property and asking how they might have become fixed. And CB is also right that this is a domain in which comparative cognition/biology would be very useful (and has already been started (see note 2). It is less clear that any of this applies to explaining the evolution of the Basic Property itself.

If this is right, it is hard for me to understand CB’s criticism of B&C’s identification of hierarchical recursion as a very central distinctive feature of FL and asking how it could have emerged.  CB seems to accept this point at times (“such a property unquestionably exists” (3)) but thinks that B&C are too obsessed with it. But this seems to me an odd criticism. Why? Because B&C’s way into the ling-evo issues is exactly the right way to study the evolution of any trait: First identify the trait of interest. Second, explain how it could have emerged.  B&C identify the trait (viz. hierarchical recursion) and explain that it arose via the one time (non-gradual) emergence of a recursive operation like Merge. The problem with lots of evo of lang work is that it fails to take the first step of identifying the trait at issue. But absent this any further evolutionary speculation is idle. If one concedes that a basic feature of FL is the Basic Property, then obsessing about how it could have emerged is exactly the right way to proceed.

Furthermore, and here I think that CB’s discussion is off the mark, it seems pretty clear that this property is not going to be all that amenable to any thing but a “top-down, all-or-nothing” account. What I mean is that recursion is not something that takes place in steps, a point that Dawkins made succinctly in support of Chomsky’s proposal (see here). As he notes, there is no such thing as “half recursion” and so there will be no very interesting “descent with modification” account of this property. Something special happened in humans. Among other things this led to hierarchical recursion. And this thing, whatever it was, likely came in one fell swoop. This might not be all there is to say about language, but this is one big thing about it and I don’t see why CB is resistant to this point. Or, put another way, even if CB is right about many other features of language being distinctive and amenable to more conventional evo analysis, it does not gainsay the fact that the Basic Property is not one of these.

There is actually a more exorbitant possibility that perhaps CB is reacting to. As the review notes (7): “Language is special, but not all that special; all creatures have special abilities.” I don’t want to over-read this, but one way of taking it is that different “abilities” supervene on common capacities. This amounts to a warning not to confuse apparent expressions of capacities for fundamental differences in capacities. This is a version of the standard continuity thesis (that Lenneberg, among others, argued is very misleading (i.e. false) wrt language). On this view, there is nothing much different in the capacities of the “language ready” brain from the “language capable” brain. They are the same thing. In effect, we need add nothing to an ape brain to get ours, though some reorganization might be required (i.e no new circuits). I personally don’t think this is so. Why? For the traditional reasons that Chomsky and IT note, namely that nothing else looks like it does language like we do, even remotely. And though I doubt that hierarchical recursion is the whole story (and have even suggested that something other than Merge is the secret sauce that got things going), I do think that it is a big part of it and that downplaying its distinctiveness is not useful.

Let me put this another way. All can agree that evolution involves descent with modification. The question is how big a role to attribute to descent and how much to modification (as well as how much modification is permitted). The MP idea can be seen as saying that much of FL is there before Merge got added. Merge is the “modification” all else the “descent.” There will fe features of FL continuous with what came before and some not continuous. No mystery about the outline of such an analysis, though the details can be very hard to develop. At any rate, it is hard for me to see what would go wrong if one assumed that Merge (like the third color neuron involved in trichromatic vision (thx Bill for this)) is a novel circuit and that FL does what it does by combining the powers of this new operation with those cognitive/computational powers inherited from our ancestors. That would be descent with modification. And, so far as I can tell, that is what a standard MP story like that in B&C aims to deliver. Why CB doesn’t like (or doesn’t appear to like) this kind of story escapes me.

Observe that how one falls on the distinctiveness of BC issue relates to what one thinks of the short time span observation (i.e. language is of recent vintage so there is little time for natural selection or descent with modification to work its magic). The view Chomsky (and Berwick and Dawkins and Tatersall) favor is that there is something qualitatively different between language capable brains and ones that are not. This does not mean that they don’t also greatly overlap. It just means that they are not capacity congruent. But if there is a qualitative difference (e.g. a novel kind of circuit) then the emphasis will be on the modifications, not the descent in accounting for the distinctiveness. B&C is happy enough with the idea that FL properties are largely shared with our ancestors. But there is something different, and that difference is a big deal. And we have a pretty good idea about (some of) the fine structure of that difference and that is what Minimalist linguistics should aim to explain.[4] Indeed, I have argued and would continue to argue that the name of the Minimalist game is to explain these very properties in a simple way. But I’ve said that already here, so I won’t belabor the point (though I encourage you to do so).

A few more random remarks and I am done. The IT piece provides a quick overview of how distinctive human symbolic (linguistic?) capacities are. In IT’s view, very. In IT’s view, the difference also emerged very recently, and understanding that is critical to understanding modern humans. And he is not alone. The reviewee Genevieve von Petziger appears to take a similar view, dating the start of the modern human mind to about 80kya (2). All this fits in with the dates that Chomsky generally assumes. It is nice to see that (some) people expert in this area find these datings and the idea that the capacity of interest is unique to us credible. Of course, to the degree that this dating is credible and to the degree that this is not a long time for evolution to exercise its powers the harder the evolutionary problem becomes. And, of course, that’s what makes the problem interesting. At any rate, what the IT review makes clear is that the way Chomsky has framed the problem is not without reasonable expert support. Whether this view is correct, is, of course, an empirical matter (and hence beyond my domain to competently judge).

Ok, let me mention two more intellectual confections of interest and we are done. I will be short.

The first is a review of Wolfe’s book by David Lobina and Mark Brenchley. It is really good and I cannot recommend it highly enough. I urge you in particular to read the discussion on recursion as self-reference vs self-embedding and the very enlightening discussion of how Post’s original formalism (might have) led to some confusion on these issues. I particularly liked the discussion of how Merge de-confuses them, in effect by dumping the string based conception of recursion that Post’s formalism used (and which invited a view of recursion as self-embedding) and implementing the recursive idea more cleanly in a Merge like system in which linguistic structures are directly embedded in one another without transiting through strings at all. This cleanly distinguishes the (misleading) idea that the recursion lies with embedding clauses within clauses from the more fundamental idea that recursion requires some kind of inductive self-reference. Like I said, the discussion is terrific and very useful.

And now for desert: read David Adger’s fun review of Arrival. I confess that I did not really like the movie that much, but after reading David’s review, I intend to re-see it with a more open mind.

That’s it. Take a look at the issue of Inference. It’s nice to see serious linguistic issues intelligently discussed in a non-specialist’s venue. It can be done and done well. We need more of it.

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[1] Chomsky also mentions that how lexical items have very distinctive properties and that we understand very little about them. This ahs become a standard trope in his essays, and a welcome one. It seems that lexical items are unlike animal signs in that the latter are really “referential” in ways that the former are not. The how and whys behind this, however, is completely opaque.

[2] There has been quite a lot of interesting comparative work done, most prominently by Berwick, on relating human phonology with bird song. See here and here for some discussion and links.

[3] There is another possibility: once FLN is in place there is only one way to retrofit all the components of FLW. If so, then there is no selection going on here and so the fact that all those endowed with FLNs share common FLWs would not require a common ancestor for the FLWs. Though I know nothing about these things, this option strikes me as far-fetched. If it is, then the logic that Chomsky has deployed for arguing that FLN was in place before humans went their separate ways would hold for FLW as well.

[4] CB makes a claim that is often mooted in discussions about biology. It is Dobzhansky’s dictum that nothing in biology makes sense except in the light of evolution. I think that this is overstated. Lots of biology “makes sense” without worrying about origin. We can understand how hearts work or eyes see or vocal tracts produce sounds without knowing anything at all about how they emerged. This is not to diss the inquiry: we all want to know how things came to be what they are. But the idea that natural selection is the only thing that makes sense of what we see is often overblown, especially so when Dobzhansky quotes are marshaled. For some interesting discussion of this see this.

Cedric Boeckx replies to some remarks by Hornstein on Berwick and Chomsky's "Why Only Us"

Norbert Hornstein commented on my "quite negative" review of Berwick and Chomsky's book _Why Only Us_ published in Inference (http://inference-review.com/article/not-only-us). Here is the link to his comments, posted here on the Faculty of Language blog: http://facultyoflanguage.blogspot.com.es/2017/04/inference-to-some-great-provocations.html

I want to begin by thanking him for reading the review and sharing his thoughts. The gist of his remarks is, if I read him right, that he is "not sure" what I find wrong with _Why Only Us_. He concludes by saying that "Why [Boeckx] doesn’t like (or doesn’t appear to like) this kind of story escapes me." I found the paragraphs he devotes to my review extremely useful, as they articulate, with greater clarity than what I could find in _Why Only Us_, some of the intuitions that animate the kind of evolutionary narrative advocated in the book I reviewed: The "All you need is Merge" approach. Hornstein's points give me the opportunity to stress some of the reasons why I think this kind of approach is misguided. This is what I want to express here.

In so far as I can see, Hornstein makes the following claims (which are, indeed, at the heart of _Why Only Us_) [the claims appear in roughly the order found on Hornstein's original post]

1. Hornstein seems to endorse Tattersall's oft-repeated claim, used in Why Only Us, that there is a link between linguistic abilities and the sort of symbolic activities that have been claimed to be specific to humans. This is important because the fossil evidence for these activities is used to date the emergence of the modern linguistic mind; specifically, to argue for a very recent emergence of the modern language faculty. Here is the relevant passage:

"in contrast to CB [Boeckx], IT [Tattersall] thinks it pretty clear that this “symbolic activity” is of “rather recent origin” and that, “as far as can be told, it was only our lineage that achieved symbolic intelligence with all of its (unintended) consequences” (1). If we read “symbolic” here to mean “linguistic” (which I think is a fair reading), it appears that IT is asking for exactly the kind of inquiry that CB thinks misconceived."

Perhaps it is too strong to say that Hornstein endorses it, but clearly he does not buy my skepticism towards this kind of argument, expressed in my review (and backed up with references to works questioning Tattersall that unfortunately Hornstein does not discuss, delegating to Tattersall as the unique expert.)

2. Hornstein grants me "several worthwhile points"; specifically, my claims that "there is more to language evolution than the emergence of the Basic Property (i.e. Merge and discretely infinite hierarchically structured objects) and that there may be more time available for selection to work its magic than is presupposed". Hornstein writes that "many would be happy to agree that though BP is a distinctive property of human language it may not be the only distinctive linguistic property." He continues "CB is right to observe that if there are others (sometimes grouped together as FLW vs FLN) then these need to be biologically fixed and that, to date, MP has had little to say about these. One might go further; to date it is not clear that we have identified many properties of FLW at all. Are there any?" Later on, he writes "CB is quite right that it behooves us to start identifying distinctive linguistic properties beyond the Basic Property and asking how they might have become fixed. And CB is also right that this is a domain in which comparative cognition/biology would be very useful", but stresses that "It is less clear that any of this applies to explaining the evolution of the Basic Property itself."

3. Hornstein seems to think that my problem is that I "think that B[erwick]&C[homsky] are too obsessed with" recursion (or Merge). He goes on: "But this seems to me an odd criticism. Why? Because B&C’s way into the ling-evo issues is exactly the right way to study the evolution of any trait: First identify the trait of interest. Second, explain how it could have emerged.  B&C identify the trait (viz. hierarchical recursion) and explain that it arose via the one time (non-gradual) emergence of a recursive operation like Merge. The problem with lots of evo of lang work is that it fails to take the first step of identifying the trait at issue. ... If one concedes that a basic feature of FL is the Basic Property, then obsessing about how it could have emerged is exactly the right way to proceed"

4. He thinks that my "discussion is off the mark" (specifically, my insistence on descent with modification and bottom-up approaches in the review) because Merge "is not going to be all that amenable to any thing but a “top-down, all-or-nothing” account". "What I mean", Hornstein says, "is that recursion is not something that takes place in steps"; "there is no such thing as “half recursion” and so there will be no very interesting “descent with modification” account of this property. Something special happened in humans. Among other things this led to hierarchical recursion. And this thing, whatever it was, likely came in one fell swoop. This might not be all there is to say about language, but this is one big thing about it and I don’t see why CB is resistant to this point."

5. Hornstein stresses that he "doubt[s] that hierarchical recursion is the whole story (and have even suggested that something other than Merge is the secret sauce that got things going), I do think that it is a big part of it and that downplaying its distinctiveness is not useful." He goes on: we "can agree that evolution involves descent with modification. The question is how big a role to attribute to descent and how much to modification (as well as how much modification is permitted). The MP idea can be seen as saying that much of FL is there before Merge got added. Merge is the “modification” all else the “descent.” "No mystery about the outline of such an analysis, though the details can be very hard to develop"... "it is hard for me to see what would go wrong if one assumed that Merge (like the third color neuron involved in trichromatic vision (thx Bill for this)) is a novel circuit and that FL does what it does by combining the powers of this new operation with those cognitive/computational powers inherited from our ancestors. That would be descent with modification"

6. He sums up: "The view Chomsky (and Berwick and Dawkins and Tattersall) favor is that there is something qualitatively different between language capable brains and ones that are not. This does not mean that they don’t also greatly overlap. It just means that they are not capacity congruent. But if there is a qualitative difference (e.g. a novel kind of circuit) then the emphasis will be on the modifications, not the descent in accounting for the distinctiveness. B&C is happy enough with the idea that FL properties are largely shared with our ancestors. But there is something different, and that difference is a big deal. And we have a pretty good idea about (some of) the fine structure of that difference and that is what Minimalist linguistics should aim to explain"

All of these are interesting points, although I think they miss the target, for reasons worth making explicit (again), if only because that way we can know what is likely to be productive and what is not. After all, I could be wrong, and Hornstein (and Berwick/Chomsky in Why Only Us) could be wrong. I'll tackle Hornstein's points in a somewhat different order from the one he used, but I don't think that doing so introduces any misrepresentation.

Let's begin with points of (apparent) agreement: Hornstein is willing to concede that we need a bit more than Merge, although if I read him well, he is not as clear about it as I would like. Why do I say so? On the one hand, he writes that "many would be happy to agree that though BP is a distinctive property of human language it may not be the only distinctive linguistic property. CB is right to observe that if there are others (sometimes grouped together as FLW vs FLN) then these need to be biologically fixed and that, to date, MP has had little to say about these. One might go further; to date it is not clear that we have identified many properties of FLW at all. Are there any?" On the other hand, he writes  "CB is also right that this is a domain in which comparative cognition/biology would be very useful (and has already been started [FN:There has been quite a lot of interesting comparative work done, most prominently by Berwick, on relating human phonology with bird song").

I won't comment much on the references provided by Hornstein in that footnote, but I must say that I think it reveals too much of a bias towards work done by linguists. In my opinion, the great comparative work that exists has not been done by linguists (in the narrow sense of the term). Hornstein's is not a lovely bias to display in the context of interdisciplinarity (indeed, it's not good to show this bias on a blog that likes to stress so much that people in other disciplines ignores the work of linguists. Don't do unto others ...) In the case of birdsong, this kind of work goes several decades back, and detailed studies like Jarvis 2004(!), or Samuels 2011 (cited in my review) hardly justify the "has already been started" claim about comparative cognition. But let's get to the main point: we can't just ask "are there any? (shared features)" and at the same time cite work that shows that there is a lot of it. But there is something worse, in light of my review: Hornstein seems to have no problem with the usefulness of comparative cognition ("a domain in which comparative cognition/biology would be very useful") so long as it applies to everything except Merge ("there will be no very interesting “descent with modification” account of this property"; "It is less clear that any of this applies to explaining the evolution of the Basic Property itself." "this property is not going to be all that amenable to any thing but a “top-down, all-or-nothing” account") This is one of the issues I intended to bring up in the review, and what I called "exceptional nativism". I'll return to this below, but for now, let me stress that even if Hornstein grants me that there is more than Merge, Merge is still special, in a way that is different from "other distinctive linguistic properties".

It's not the case that I object to _Why Only Us_ because I think Berwick and Chomsky are "too obsessed with Merge". I object to it because I think they obsess about it in the wrong way: they (and Hornstein) are obsessed in making it not only special, but distinct-in-a-way-that-other-distinct-things-are-not: it takes it out of the Darwinian domain of descent with modification.

Hornstein discusses Descent With Modification, but his prose reveals that he and I understand it differently. Indeed, he appears to understand it in a way that I warned against in my review. Here is the key passage: "the MP idea can be seen as saying that much of FL is there before Merge got added. Merge is the “modification” all else the “descent.” " I think this is wrong. It takes the phrase descent with modification pretty much like most linguists understood the FLN/FLB distinction of Hauser, Chomsky and Fitch 2002: there is FLN and there is FLB. There is descent and there is modification. But I don't think this is the core of the Darwinian logic: "Descent with modification" ought to be understood as "modified descent" (tinkering), not as "descent" put side by side with/distinct from modification. Because modification is modification of something shared; it's inextricably linked to descent. Descent with modification is not "this is shared" and "this is different" and when you put these 2 things you get "descent and modification", because the different is to be rooted in the shared. We can't just say Merge is the 'modification' bit unless we say what it is a modification of. (Needless to say, if, as Hornstein writes, we replace Merge by some other "secret sauce that got things going", my point still applies. The problem is with thinking in terms of some secret sauce, unless we break it down in no so secret ingredients, ingredients that can be studied, in isolation, in other species. That's the message in my review.)

The Darwinian logic is basically that the apple can only fall so far from the tree. The apple is not the tree. But it is to be traced back to the tree. As I put it in the review: there's got to be a way from there (them) to here (us). And Merge should not be any exception to this. I'll put it this way: if the way we define Merge makes it look like an exception to this kind of thinking, then we are looking (obsessing?) at Merge in the wrong way. If we find Merge interesting (and I do!), then we've got to find a way (or better, several ways, that we can then test) to make it amenable to "descent with modification"/"Bottom-up (as opposed to all-or-nothing/top-down) approaches. Of course, we could say, well, tough luck: we can't choose what nature gave us. It gave us Merge/recursion, and you can't understand this gradually. It's there or not. It's discontinuous but in a way different from the kind of discontinuity that biologists understand (significantly modified descent). But if we do so, then, tough luck indeed: we are confining Darwin's problem to a mystery. A fact, but a mysterious one ("Innate knowledge is a mystery, though a fact", as McGinn once put it.) It's fine by me, but then I can't understand how people can write about how "All you need is Merge" accounts shedding light on Darwin's problem. They must mean Darwin's mystery. To use Hume's phrase, such accounts restore Merge to that obscurity, in which it ever did and ever will remain”.

Don't get me wrong. It's a perfectly coherent position. Indeed, in a slightly different context, referenced in my review, David Poeppel talks about the "incommensurability problem" of linking mind and brain. Maybe we can't link both, just like we can't understand the evolution of Merge. Note here that I say the evolution of Merge. At times, Hornstein, like Berwick and Chomsky, gives me the impression that he thinks Merge is the solution. But it's the problem. It's that which needs to be explained. And I think that one way to proceed is to understand its neural basis and trace back the evolution of that (that is, engage with Poeppel's granularity mismatch problem, not endorse his incommensurability problem), because perhaps Merge described at the computational level (in Marr's sense) is mysterious from a descent-with-modification perspective, but not so at the algorithmic and implementational levels. And I think  it's the task of linguists too to get down to those levels (jointly with others), as opposed to lecturing to biologists about how Merge is the solution, and it's their problem if they don't get it. (Incidentally, it's a bit ironic that Hornstein praises Lobina's discussion of recursion in his blog post, but does not mention the fact that Lobina took issue with Hornstein's take on recursion in some of his publications.)

Hornstein writes that "The problem with lots of evo of lang work is that it fails to take the first step of identifying the trait at issue". He does not give references, so I cannot judge what he means by "lots". I like to think I read a lot, and my assessment doesn't match Hornstein's at all. I think a lot of work in evo of lang promotes a Darwinian feeling for the phenotype. This is quite different from, say, a Darcy-Thompsonian feeling for the phenotype. I see in lots of evo of lang work a desire to make talk about evo of language amenable to conventional evolutionary discourse. Why Only Us ("this property is not going to be all that amenable to any thing but a “top-down, all-or-nothing” account") is the exact opposite.

Perhaps a bit of an empirical discussion would help (I always find it helpful, but I don't know if Hornstein would agree here). Let's take the example of vocal learning, a key component of our language-faculty-mosaic. Not a cool as Merge for some, but still pretty neat. In fact, the way many talks and papers about vocal learning begin is quite like the way linguists like to talk about Merge. Let me spell this out. It's often pointed out that vocal learning  (the ability to control one's vocal apparatus to reproduce sounds one can hear, typically from con-specifics) is a fairly sparsely distributed trait in the animal kingdom. It may not be as unique as Merge ("Only us"), but it's close: it's "only" for a selected few. (I stress that I am talking about the classic presentation of this trait; ideas of a vocal learning continuum, which I like, would only make the point I am about to make stronger. See work by Petkov and Jarvis on this.) Like Merge, Vocal learning is an all or nothing affair. You have it, or you don't. It looks like an all or nothing thing. But unlike Merge, people have been able to gain insight into its neural structure, and break it down to component pieces. Among these, there is a critical cortico-laryngeal connection that appears to qualify for the "new circuit" that underlies vocal learning (see Fitch's book on evolution of language for references). And people have been able to get down to the molecular details for birds (Erich Jarvis, Constance Scharff, Stephanie White, and many others), bats (Sonja Vernes), and link it to language/speech (Simon Fisher and lots of people working on FOXP2). Erich Jarvis in particular has been able to show that most likely this new circuit has a motor origin, and "proto" aspects of it may be found in non-vocal learning birds (suboscines). All of this is quite rich in terms of insight. And this richness (testability, use of comparative method, etc.) makes the Merge solution to Darwin's problem pale in comparison. It's true, as Hornstein points out,  linguists know a lot about Merge, but they only know it from one perspective (the "Cartesian" perspective, the one that leads to "Why Only Us"), and this may not be the most useful perspective from a Darwinian point of view. The main message of my review  of Why Only Us was that.

Final point, on timing, and Hornstein's appeal to Tattersal's review of the fossil evidence for the emergence of symbolic behavior. No one can know everything (where would one put it?, as they say), but in my experience it's always good to rely on more than one expert (I cite some in the review). My main point about this in the review was not so much to question the dating of said emergence, but rather to ask for an account of how symbolic behavior is linked to linguistic behavior. I can see why it's plausible to think these are linked. But if the argument concerning the timing of the emergence of the language faculty rests on very few things, and it's one of them, we want more than a plausibility argument. (Norbert's blog loves to say "show me the money" when non-generativists make claims about language acquisition based on what strikes them as plausible. I guess, it's only fair to say "show me the money", or else I'll start selling Hornstein bridges.) It's plausible to think "how could they have done it without language". So, symbol, ergo language. But then again, I can't remember how I lived without my iphone. Poverty of Imagination arguments can be very weak. I know of very few attempts to mechanistically link symbolic and linguistic behavior. One attempt, by Juan Uriagereka, was about "knots" and the Chomsky hierarchy. David Lobina showed how this failed in a paper entitled "much ado about knotting". Victor Longa tried to link blombos style marks to crossing dependencies in language, but it's fair to say the argument for crossing dependencies there is nowhere near as neat as what Chomsky did in Syntactic Structures. Apart from that, I am not aware of any explanatory attempt. I once asked Tattersal after a talk he gave, and he told me something that amounted to "ask Chomsky". When I ask linguists, they tell me ask the experts like Tattersall. And so I begin to be suspicious...

But there is something more I could say about the timing issue that came to my mind when reading Hornstein's comments: if Merge is such an all-or-nothing thing, not subject to the logic of descent, then why should we care if it's recent or not? It could have emerged, in one fell swoop, millions of years ago, and remain "unattached" to "speech devices" until recently. And so why do we want to insist about a very recent origin? The timing issue is only very important if issues about gradual evolution matters. But if we stress that gradual evolution is out of the question, then, the timing issue is a red herring. So, why does Hornstein insist on it?

Let me close by thanking Norbert again for his comments. They led to this long post. But they often made me feel like Alice when she tells the Red Queen that one can't believe impossible things. Hornstein, like the Red Queen, disagrees. But it's not Wonderland, it's Darwinland.