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.

How to make an EVOLANG argument

Bob Berwick recently sent me something that aims to survey, albeit sketchily, the state of play in the evolution of language (evolang) and a nice little paper surveying the current state of Gould and Lewontin’s spandrels paper (here) (hint: their warning is still relevant). There have also been more than a few comments in FOL threads remarking on the important progress that has been made on evolang. I believe that I have invited at least one evolang enthusiast to blog about this (I offered as much space as desired, in fact) so as to enlighten the rest of us about the progress that has been made. I admit that I did this in part because I thought that the offer would not be taken up (a put up or shut-up gambit) and also (should the challenge be accepted) because I would really be interested in knowing what has been found given my profound skepticism that at this moment in time there is anything much to find.  In other words, for better or for worse, right now I doubt that there is much substantive detail to be had about how language actually evolved in the species.[1] In this regard, we are not unlike the Paris Academy over a century ago when it called for a moratorium on such speculation.

That said, who can resist speculating? I can’t. And therefore, this post was intended to be an attempt to examine the logic of an evolution of language account that would satisfy someone like me. I wanted to do this, because, though close to vacuous most of the discussion I’ve seen is (like the fancy inversion here?), I think that Minimalism has moved the discussion one small conceptual step forward. So my intention had been to outline what I think this small step is as well as point to the considerable distance left to travel.  

As you can tell from the modal tenses above, I was going to do this, but am not going to do it. Why not? Because someone has done this for me and instead of my laying out the argument I will simply review what I have received. The text for the following sermon is here, a recent paper by Chomsky on these matters.[2] It is short, readable and (surprise, surprise) lays out the relevant logic very well. Let’s go through the main bits.

Any discussion of evolang should start with a characterization of what features of language are being discussed. We all know that “language” is a very complex “thing.” Any linguist can tell you that there are many different kinds of language properties. Syntax is not phonology is not semantics. Thus in providing an evolutionary account of language it behooves a proposal to identify the properties under consideration.

Note that this is not an idiosyncratic request. Evolution is the study of how biological entities and capacities change over time. Thus, to study this logically requires a specification of the entity/capacity of interest. This is no less true for the faculty of language (FL) than it is for hearts, kidneys or dead reckoning. So, to even rationally begin a discussion in evolang requires specifying the properties of the linguistic capacity of interest.

So, how do we specify this in the domain of language? Well, here we are in luck. We actually have been studying these linguistic capacities for quite a while and we have a rich, developed, and articulate body of doctrine (BOD) that we can pull from in identifying a target of evolutionary interest. Chomsky identifies one feature that he is interested in. He terms this the “Basic Property” (BP) and describes it as follows:

[E]ach language yields a digitally infinite array of hierarchically structured expressions with systematic interpretations at interfaces with two other internal systems, the sensorymotor system for externalization and the conceptual system, for interpretation, planning, organization of action, and other elements of what are informally called “thought.” (1)

So one evolang project is to ask how the capacity that delivers languages with these properties (viz. I-languages) arose in the species. We call the theory of I-languages “Universal Grammar” or UG as it “determines the class of generative procedures that satisfy the Basic Property” (1). We can take UG as “the theory of the genetic component of the faculty of language.” If we do, there is a corresponding evolang question: how did UG arise in the species?[3]

Note, that the above distinguishes FL and UG. FL is the mental system/”organ” that undergirds the human linguistic competence (ie. The capacity to develop (viz. “grow”) and deploy (viz. “use”) I-languages). UG is the linguistically specific component of FL. FL is likely complex, incorporating many capacities only some of which are linguistically proprietary. Thus, UG is a subpart of FL. One critical evolang question then is how much of FL is UG. How much of FL consists of linguistically proprietary properties, capacities/primitives that are exclusively linguistic?

Why is the distinction important? Well, because it sure looks like humans are the only animals with BP (i.e. nothing does language like humans do language!) and it sure looks like this capacity is relatively independent of (viz. dissociates with) other cognitive capacities we have (see here). Thus, it sure looks like the capacity to generate BP-I-languages (BPIs) is a property of humans exclusively. And now we come to the interesting evolang problem: as a point of evolutionary logic (we might dub this the Logical Problem of Language Evolution (LPLE)) the bigger the UG part of FL, the more demanding the problem of explaining the emergence of FL in the species. Or as Chomsky puts it (3): “UG must meet the condition of evolvability, and the more complex its assumed character, the greater the burden on some future account of how it might have evolved.”

We can further sharpen the evolvability problem by noting one more set of boundary conditions on any acceptable account. There are two relevant facts of interest, the first “quite firm” and the second “plausible” and that we refer to with “less confidence.”  These are:

1.     There has been no evolution of FL in the species in the last 50k years or more.

2.     FL emerged in the way it exists today about 75k years ago.

As Chomsky puts it (3): “It is, for now, a reasonable surmise that language –more accurately UG- emerged at some point in the very narrow window of evolutionary time, perhaps in the general neighborhood of 75 thousand years ago, and has not evolved since.”[4]

Why is (1) firm? Because there are no known group differences in the capacity humans have in acquiring and using a natural language. As the common wisdom is that our ancestors left Africa and their paths diverged about 50kya then this would be unexpected were there evolution of FL or UG after this point.

Why is (2) less firm? Because we infer it to be true based on material cultural artifacts that are only indirect indicators of linguistic capacity. This evidence has been reviewed by Ian Tattersal (here) and it looks like the conclusion he draws on these issues is a plausible one. Chomsky is here relying on this archeological “consensus” view for his “plausible” second assumption.

If these assumptions are correct then, as Chomsky notes (3)  “UG must be quite simple at its core” and it must have emerged more or less at once. These are really flip sides of the same claim. The evolutionary window is very narrow and so whatever happened must have happened quickly in evo-time and for something to happen quickly it is very likely that what happened was a small simple change. Complexity takes a long time. Simplicity not so much.[5] So, what we are looking for in an evolang account of our kinds of natural langauges is some small change that has BPI-effects. Enter Minimalism.

Chomsky has a useful discussion of the role of evolvability in early Generative Grammar (GG). He notes that the evolvability of FL/UG was always recognized to be an important question and that people repeatedly speculated about it. He mentions Lenneberg and Luria in this regard, and I think I recall that there was also some scattered discussion of this in the Royaumont conference. I also know that Chomsky discussed these issues with Francois Jacob as well. However, despite the interest of the problem and the fact that it was on everyone’s radar the speculation never got very far. Why not? Because of the state of the theory of UG.  Until recently, there was little reason for thinking that UG was anything but a very complicated object with complex internal structure, many different kinds of primitives, processes and conditions (e.g. just take a look at GB theory). Given the LPLE, this made any fruitful speculation idle, or, in Dwight Whitney’s words quoted by Chomsky: “The greater part of what is said and written about it is mere windy talk” (4) (I love this Ecclesiastical description: Wind, wind, all is wind!).

As Chomsky notes, minimalism changed this. How? By suggesting that the apparent complexity of UG as seen from the GB angle (and all of GB’s close relatives) is eliminable. How so? By showing that the core features of BPIs as described by GB can be derived from very a simple rules (Merge) applied in very simple ways (computationally “efficient”). Let me say this more circumspectly: if to the degree that MP succeeds to that degree the apparent complexity of FL/UG can be reduced. In the best case, the apparent complexity of BPIs reduces to one novel language specific addition to the human genome and out falls our FL.  This one UG addition together with our earlier cognitive apparatus and whatever non-cognitive laws of nature are relevant suffice to allow the mergence of the FL we all know and love. If MP can cash this promissory note, then we have taken a significant step towards solving the evolang problem.

Chomsky, of course, rehearses his favorite MP account (7-9): the simplest Merge operation yielding unordered merges, the simplest application of the rule to two inputs yielding PS rules and Movement, natural computational principles (not specific to language but natural for computation as such) resulting in conditions like Inclusiveness and Extension and something like phases, the simple merge rule yielding a version of the copy theory of movement with obvious interpretive virtues etc.  This story is well known, and Chomsky rightly sees that if something like this is empirically tenable then it can shed light on how language might have evolved, or, at the very least, might move us from windy discussions to substantive ones.

Let me say this one more way: what minimalism brings to the table is a vision of how a simple addition might suffice to precipitate an FL like the one we think we have empirical evidence for. And, if correct, this is, IMO, a pretty big deal. If correct, it moves evolang discussion of these linguistic properties from BS to (almost) science, albeit, still of a speculative variety.

Chomsky notes that this does not exhaust the kinds of evolang questions of interest. It only addresses the questions about generative procedure. There are others. One important one regards the emergence of our basic lexical atoms (“words”). These have no real counterpart in other animal communication systems and their properties are still very hard to describe.[6] A second might address how the generative procedure hooked up to the articulatory system. It is not unreasonable to suppose that fitting FL snugly to this interface took some evolutionary tinkering. But though questions of great interest remain, Chomsky argues, very convincingly in my view, that with the rise of MP linguistics has something non-trivial to contribute to the discussion: a specification of an evolvable FL.

There is a lot more in this little paper. For example, Chomsky suggests that much of the windiness of much evolang speculation relates to the misconceived notion that the natural language serves largely communicative ends (rather than being an expression of thought). This places natural languages on a continuum with (other) animal communication systems, despite the well-known huge apparent differences. 

In addition, Chomsky suggests what he intends with the locution ‘optimal design’ and ‘computationally efficient.’ Let me quote (13):

Of course, the term “designed” is a metaphor. What it means is that the simplest evolutionary process consistent with the Basic Property yields a system of thought and understanding [that is sic (NH)] computationally efficient since there is no external pressure preventing this optimal outcome.

“Optimal design” and “computational efficiency” are here used to mean more or less the same thing. FL is optimal because there is no required tinkering (natural selection?) to get it into place.  FL/UG is thus evolutionarily optimal. Whether this makes it computationally optimal in any other sense is left open.[7]

Let me end with one more observation. The project outlined above rests on an important premise: that simple phenotypic descriptions will correspond to simple genotypic ones. Here’s what I mean. Good MP stories provide descriptions of mental mechanisms, not  neural or genetic mechanisms. Evolution, however, selects traits by reconfiguring genes or other biological hardware. And, presumably, genes grow brains, which in turn secrete minds. It is an open question whether a simple mental description (what MP aims to provide) corresponds to a simple brain description, which, in turn, corresponds to a simple “genetic” description. Jerry Fodor describes this train of assumptions well here.[8]

…what matters with regard to the question whether the mind is an adaptation is not how complex our behaviour is, but how much change you would have to make in an ape’s brain to produce the cognitive structure of a human mind. And about this, exactly nothing is known. That’s because nothing is known about how the structure of our minds depends on the structure of our brains. Nobody even knows which brain structures it is that our cognitive capacities depend on.

Unlike our minds, our brains are, by any gross measure, very like those of apes. So it looks as though relatively small alterations of brain structure must have produced very large behavioural discontinuities in the transition from the ancestral apes to us…

…In fact, we don’t know what the scientifically reasonable view of the phylogeny of behaviour is; nor will we until we begin to understand how behaviour is subserved by the brain. And never mind tough-mindedness; what matters is what’s true.

In other words, the whole evolang discussion rests on a rather tendentious assumption, one for which we have virtually no evidence; namely that a “small” phenotypic change (e.g. reduction of all basic grammatical operations to Merge) corresponds to a small brain change (e.g. some brain fold heretofore absent all of a sudden makes an appearance), which in turn corresponds to a small genetic change (e.g. some gene gets turned on during development for a little longer than previously).  Whether any of this is correct is anyone’s guess. After all there is nothing incoherent in thinking that a simple genetic change can have a big effect on brain organization, which in turn corresponds to a very complex phenotypic difference. The argument above assumes that this is not so, but the operative word is “assume.” We really don’t know.

There is another good discussion of these complex issues in Lenneberg’s chapter 6, which is worth looking at and keeping in mind. This is not unusual in the evolution literature, which typically assumes that traits (not genes) are the targets of selection. But the fact that this is commonly the way that the issues are addressed does not mean that the connections assumed from phenotypic mental accounts to brains to genes are straightforward. As Fodor notes, correctly I believe, they are not.

Ok, that’s it. There is a lot more in the paper that I leave for your discovery. Read it. It’s terrific and provides a good model for evolang discussions. And please remember the most important lesson: you cannot describe the evolution of something until you specify that thing (and even then the argument is very abstract). So far as I know, only linguists have anything approaching decent specifications of what our linguistic capacities consists in. So any story in evolang not starting from these kinds of specifications of FL (sadly, the standard case from what I can tell) are very likely the windy products of waving hands. 

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[1] Happily, I have put myself in the good position of finding out that I am wrong about this. Marc Hauser is coming to UMD soon to give a lecture on the topic that I am really looking forward to. If there are any interesting results, Marc will know what they are. Cannot wait.

[2] I’d like to thank Noam for allowing me to put this paper up for public consumption.

[3] Please observe that this does not imply that BP is the only property we might wish to investigate, though I agree with Chomsky that this is a pretty salient one. But say one were interested in how the phonological system arose, or the semantic system. The first step has to be to characterize the properties of the system one is interested. Only once this is done can evolutionary speculation fruitfully proceed. See here for further discussion, with an emphasis on phonology.

[4] It is worth noting that this is very fast in evolutionary terms and that if the time scale is roughly right then this seems to preclude a gradualist evolutionary story in terms of the slow accretion of selected features. Some seem to identify evolution with natural selection. As Chomsky notes (p. 11), Darwin himself did not assume this.

[5] Furthermore, we want whatever was added to be simple because it has not changed for the last 50k years. Let me say this another way: if what emerged 100kya was the product of slow moving evolutionary change with the system accreting complexity over time then why did this slow change stop so completely 50kya? Why didn’t change continue after the trek out of Africa? Why tones of change before hand and nothing since? If the change is simple, with not moving parts, as it were, then there is nothing in the core system to further evolve.

[6] I’ll write another post on these soon. I hope.

[7] If this reading of Chomsky’s intention here is correct, then I have interpreted him incorrectly in the past. Oh well, won’t be the last time. In fact, under this view, the linguistic system once evolved need not be particularly efficient computationally or otherwise.  On this view, computationally efficient seems to me “arose as a matter of natural law without the required intervention of natural selection.”

[8] The relevant passage is