The wildly successful minimalist program II

In an earlier post (here) I mentioned that I was asked to write about the Minimalist Program (MP) for a volume aimed at comparing various linguistic  “frameworks.” I am personally skeptical about “framework differences.” I personally find them to be more notational variants of common themes (indeed, when pressed, I have been known to complain that H/GPSG, LFG, RG, are all “dialects” of GB) than actual conceptually divergent perspectives. The main reason is that most linguistic theory lacks any real depth and most of the frameworks have the wherewithal to mimic one another’s (ahem) deep insights. So, where others see ideological divergence, I tend to see slight differences in accent.

That said, I have a further gripe about this kind of volume. Even were I to recognize that these different frameworks empirically competed (or should compete) I do not think that MP should be included in the race. MP is not an alternative to GB (or its various dialects) but presupposes that the results of GB are (largely) empirically correct. MP builds on GB results (and its dialects) and aims to conserve these results. Thus, it is not intended (or should not be intended) as a wholesale replacement. For an MPer, GB is wrong the way that Newtonian Gravitation is wrong when compared to General Relativity: the latter theory derives the former as a limiting case. It does not reject the former as misguided, rather it treats it as descriptive rather than fundamental. Indeed, an important part of the argument in favor of General Relativity is that it can derive Newton as a special case. If it could not, that would be an excellent argument that it was fundamentally flawed.

And the MP point? From the MP perspective, as M Antony might have put matters: MPers come to (largely) praise (and incorporate) GB not to bury it. The whole point of MP is to show that the “laws” that GB discovered can be understood in more fundamental MP terms. IMO, it has been less appreciated than it should be how much MP has succeeded in making good on this ambition. So, in this post (and another I will put up later on) I will try to show how far MP has come in making good on its ambitions.

A caveat: if you find GB (and its cousins) to be hopelessly wrongheaded, then you will find a theory that derives its results also hopelessly wrongheaded. If you are one of these, then MP will have, at most, aesthetic interest. If you, like me, take GB to be more or less correct, then MP’s aesthetic virtues will combine with GB’s empirical panache to create a very powerful intellectual rush. It will even create the impression that MP is very much on the right track.

The Merge Hypothesis: Explaining some core features of FL/UG

Here is a list of some characteristic features of FL/UG and its G_Ls:

(1)  a.   Hierarchical recursion

b.   Displacement (aka, movement)

c.     Gs generate natural formats for semantic interpretation

d.     Reconstruction effects

e.     Movement targets c-commanding positions

f.      No lowering rules

g.     Strict cyclicity

h.     G rules are structure dependent

i.      Antecedents c-command their anaphors

j.      Anaphors never c-command their antecedents (i.e. Principle C effects and Strong Cross Over Effects)

k.     XPs move, X’s don’t, X⁰s might

l.      Control targets subjects of “defective” (i.e. tns or agreement deficiency) clauses

m.   Control respects the Principle of Minimal Distance

n.     Case and agreement are X⁰-YP dependencies

o.     Reflexivization and Pronominalization are in complementary distribution

p.    Selection/subcategorization are very local head-head relations

q.     Gs treat arguments and adjuncts differently, with the former less “constrained” than the latter

Note, I am not saying that this exhausts the properties of FL/UG, nor am I saying that all LINGers agree with all of these accurately describe FL/UG.[1] What I am saying is that (1a-q) identify empirically robust(ish) properties of FL/UG and the generative procedures its G_Ls allow. Put another way, I am claiming (i) that certain facts about human G_Ls (e.g. that they have hierarchical recursion and movement and binding under c-command and display principle C effects and obligatory control effects, etc.) are empirically well-grounded and (ii) that it is appropriate to ask why FL/UG allows for G_Ls with these properties and not others. If you buy this, then welcome to the Minimalist Program (MP).

I would go further; not only are the assumptions in (i) reasonable and the question in (ii) appropriate, MP has provided some answers to the question in (ii). One well-known approach to (1a-h), the Merge Hypothesis (MH), unifies all these properties, deriving them from the core generative mechanism Merge. Or more particularly, MH postulates that FL/UG contains a very simple operation (aka, Merge) that suffices to generate unbounded hierarchical structures (1a) and that these Merge generated hierarchical structures will also have the seven additional properties (1b-h). Let’s examine the features of this simple operation and see how it manages to derive these eight properties?

Unbounded hierarchy implies a recursive procedure.[2] MH explains this by postulating a simple operation (“Merge”) that generates the requisite unbounded hierarchical structures. Merge consists of a very simple recursive specification of Syntactic Objects (SO) coupled with the assumption that complex SOs are sets.

(2)  a. If a is a lexical item then a is a SO[3]

b. If a is an SO and b is an SO the Merge(a,b) is an SO

(3)  For a, b, SOs, Merge(a,b)à {a,b}

The inductive step (2b) allows Merge to apply to its own outputs and thus licenses unboundedly “deep” SOs with sets contained within sets contained within sets… The Merge Hypothesis is that the “simplest” conception of this combinatoric operation (the minimum required to generate unbounded hierarchically organized objects) suffices to explain why FL/UG has many of the other properties listed in (1).

In what way is Merge the “simplest” specification of unbounded hierarchy? The operation has three key features: (i) it directly and uniquely targets hierarchy (i.e. the basic complex objects are sets (which are unordered), not strings), (ii) it in no way changes the atomic objects combined in combining them (Inclusiveness), and (iii) it in no way changes the complex objects combined in combining them (Extension). Inclusiveness and Extension together constitute the “No Tampering Condition” (NTC). Thus, Merge recursively builds hierarchy (and only hierarchy) without “tampering” with the inputs in any way save combining them in a very simple way (i.e. just hierarchy no linear information).[4] The key theoretical observation is that if FL/UG has Merge as its primary generative mechanism,[5] then it delivers G_Ls with properties (1a-h). And if this is right, it provides a proof of concept that it is not premature to ask why FL/UG is structured as it is. In other words, this would be a very nice result given the stated aims of MP. Let’s see how Merge so conceived derives (1a-h).

It should be clear that Gs with Merge can generate unbounded hierarchical dependencies. Given a lexicon containing a finite list of atoms a,b,g,d,… we can, using the definitions in (2) and (3) form structures like (4) (try it!).

            (4)       a. {a, {b, {g, d}}}

                        b.  {{a, b}, {g, d}}

                        c.  {{{a, b}, g}, d}

And given the recursive nature of the operation, we can keep on going ad libitum. So Merge suffices to generate an unbounded number of hierarchically organized syntactic objects.

Merge can also generate structures that model displacement (i.e. movement dependencies). Movement rules code the fact that a single expression can enjoy multiple relations within a structure (e.g. it can be both a complement of a predicate and the subject of a sentence).[6] Merge allows for the derivation of structures that have this property. And this is a very good thing given that we know (due to over 60 years of work in Generative Grammar) that displacement is a key feature of human G_Ls.

Here’s how Merge does this. Given a structure like (5a) consider how (2) and (3) yield the movement structure (5b). Observe that in (5b), b occurs twice. This can be understood as coding a movement dependency, b being both sister of the SO a and sister of the derived SO {g, {l, {a, b}}}. The derivation is in (6).

(5)       a. {g, {l, {a, b}}}

      b. {b, {g, {l, {a, b}}}}

(6) The SO {g, {l, {a, b}}} and the SO b (within {g, {l, {a, b}}}) merge to      from {b, {g, {l, {a, b}}}}

Note that this derivation assumes that once an SO always an SO. Thus, Merging an SO a to form part of a complex SO b that contains a does not change (tamper with) a’s status as an SO. Because complex SOs are composed of SOs Merge can target a subpart of an SO for further Merging. Thus, NTC allows Merge to generate structures with the properties of movement; structures where a SO is a member of two different “sets.”

Let me emphasize an important point: the key feature that allows Merge to generate movement dependencies (viz. the “once an SO always an SO” assumption) follows from the assumption that Merge does nothing more than take SOs and form them into a unit. It otherwise leaves the combined objects alone. Thus, if some expression is an SO before being merged with another SO then it will retain this property after being Merged given that Merge in no way changes the expressions but for combining them. NTC (specifically the Inclusiveness and Extension Conditions) leaves all properties of the combining expressions intact. So, if a has some property before being combined with b (e.g. being an SO), it will have this property after it is combined with b. As being an SO is a property of an expression, Merging it will not change this and so Merge thus legitimately combine a subpart of an SO to its container.

Before pressing on, a comment: unifying movement and phrase building is an MP innovation. Earlier theories of grammar (and early minimalist theories) treated phrasal dependencies and movement dependencies as the products of entirely different kinds of rules (e.g. phrase structure rules vs transformations/Merge vs Copy+Merge). Merge unifies these two kinds of dependencies and treats them as different outputs of a single operation. As such, the fact that FL yields Gs that contain both unbounded hierarchy and displacement operations is unsurprising. Hierarchy and displacement are flips sides of the same combinatoric coin. Thus, if Merge is the core combinatoric operation FL makes available, then MH explains why FL/UG constructs G_Ls that have both (1a) and (1b) as characteristic features.

Let’s continue. As should be clear, Merge generated structures like those in (5) and (6) also provides all we need to code the two basic types of semantic dependencies: predicate-argument structures (i.e. thematic dependency) and scope structure. Let me be a bit clearer. The two basic applications of move are those that take two separate SOs and combine them and those that take two SOs with one contained in the other and combines them. The former, E-Merge, is fit for the representation of predicate-argument (aka, thematic structure). The latter, I-Merge, provides an adequate grammatical format for representing operator/variable (i.e. scope) dependencies. There is ample evidence that Gs code for these two kinds of semantic information in simple constructions like Wh-questions. Thus, it is an argument in its favor that Merge as defined in (2) and (3) provides a syntactic format for both. An argument saturates the predicate it E-merges with and scopes over the SO it I-merges with. If this is correct, then Merge provides structure appropriate to explain (1c).

And also (1d). A standard account of Reconstruction Effects (RE) involves allowing a moved expression to function as if it still occupied the position from which it moved. This as-if is redeemed theoretically if the movement site contains a copy of the moved expression. Why does a displaced expression semantically comport itself as if it is in its base position? Because a copy of the moved expression is in the base position. Or, to put this another way, a copy theory of movement would go a long way towards providing the technical wherewithal to account for the possibility of REs. But Merge based accounts of movement like the one above embody a copy theory of movement. Look at (5b): b is in two positions in virtue of being I-merged with its container. Thus, b is a member of the lowest set and the highest. Reconstruction amounts to choosing which “copy” to interpret semantically and phonetically.[7] Reducing movement to I-merge explains why movement should allow REs.[8]

Furthermore, having this option follows from a key assumption concerning Merge. Recall that it eschews tampering. In other words, if movement is a species of Merge then no-tampering requires coding movement with “copies.” To see this contrast how movement is treated in GB.

Within GB, if a moves from its base position to some higher position a trace is left in the launch site. Thus, a GB version of (5b) would look something like (7):

            (7) {b₁, {g, {l, {a, t₁}}}}

Two features are noteworthy; (i) in place of a copy in the launch site we find a trace and (ii) that trace is co-indexed with the moved expression b.[9] These features are built into the GB understanding of a movement rule. Understood from a Merge perspective, this GB conception is doubly suspect for it violates the Inclusiveness Condition clause of the NTC twice over. It replaces a copy with a trace and it adds indices to the derived structure. Empirically, it also mystifies REs. Traces have no contents. That’s what makes them traces (see note 13). Why are they then able to act as if they did have them? To accommodate such effects GB adds a layer of theory specific to REs (e.g. it invokes reconstruction rules to undo the effects of movement understood in trace theoretic terms). Having copies in place of traces simplifies matters and explains how REs are possible. Furthermore, if movement is a species of Merge (i.e. I-merge) then SOs like (7) are not generable at all as they violate NTC. More specifically, the only kosher way to code movement and obey the NTC is via copies. So, the only way to code movement given a simple conception of syntactic combination like Merge (i.e. one that embodies no tampering) results in a copy theory of movement that serves to rationalize REs without a theoretically bespoke theory of reconstruction. Not bad![10]

So Merge delivers properties (1a-d), and the gifts just keep on coming. It also serves up (6e,f,g) as consequences. This time let’s look at the Extension Condition (EC) codicil to the NTC. EC requires that that inputs to Merge be preserved in the outputs to Merge (any other result would “change” one of the inputs). Thus, if an SO is input to the operation it will be a unit/set in the output as well because Merge does no more than create linguistic units from the inputs. Thus, whatever is a constituent in the input appears as a constituent with the same properties in the output.  This implies (i) that all I-merge is to a c-commanding position, (ii) that lowering rules cannot exist, and (iii) that derivations are strictly cyclic.[11] The conditions that movements be always upwards to c-commanding positions and strictly cyclic thus follows trivially from this simple specification of Merge (i.e. Merge with NTC understood as embodying EC).

An illustration will help clarify this. NTC prohibits deriving structure (8b) from (8a). Here we Merge g with a. The output of this instance of Merge obliterates the fact that {a,b} had been a unit/constituent in (8a), the input to Merge. EC prohibits this. It effectively restricts I-Merge to the root. So restricted, (8b) is not a licit instance of I-Merge (note that {a,b} is not a unit in the output. Nor is (8c) (note that {{a,b},{g,d}} is not a unit in the output). Nor is a derivation that violates the strict cycle (as in (8d)). Only (8e) is a grammatically licit Merge derivation for here all the inputs to the derivation (i.e. g and {{a,b},{g,d}}) are also units in the output of the derivation (i.e. thus the inputs have been preserved (remain unchanged) in the output). Yes a new relation has been added, but no previous ones have been destroyed (i.e. the derivation is info-preserving (viz. monotonic). Repeat the slogan: once an SO always an SO). In deriving (8b-c) one of the inputs (viz. {{a,b},{g,d}}) is no longer a unit in the output and so NTC/EC has been violated.

(8)       a. {{a,b},{g,d}}

b. {{{g,a},b}, {g,d}}

                        c. {{g,{a,b}},{g,d}}

                        d.  {{a, b}, {d, {g,d}}

                        d. {g,{{a,b},{g,d}}}

 In sum, if movement is I-merge subject to NTC then all movement will necessarily be to c-commanding positions, upwards, and strictly cyclic.

It is worth noting that these three features are not particularly recondite properties of FL/UG and find a place in most GG accounts of movement. This makes their seamless derivation within a Merge based account particularly interesting.

Last, we can derive the fact that the rules of grammar are structure dependent ((1h) above), an oft-noted feature of syntactic operations.[12] Why should this be so? Well, if Merge is the sole syntactic operation and then non-structure dependent operations are very hard (impossible?) to state. Why? Because the products of Merge are sets and sets impose no linear requirements on their elements. If we understand a derivation to be a mapping of phrase markers into phrase markers and we understand phrase markers to effectively be sets (i.e. to only specify hierarchical relations) then it is no surprise that rules that leverage linear left-right properties of a string cannot be exploited. They don’t exist for phrase markers eschew this sort of information and thus operations that exploit left/right (i.e. string based) information cannot be defined.  So, why are rules of G structure dependent? Because this is the only structural information that Merge based Gs represent. So, if the basic combinatoric operation that FL/UG allows is Merge, then FL/UGs restriction to structure dependent operations is unsurprising.

This is a good place to pause for a temporary summary: Research in GG over the last 60 years has uncovered several plausible design features of FL/UG. (1a-h) summarizes some uncontroversial examples. All of these properties of FL/UG can be unified if we assume that Merge as outlined in (2) and (3) is the basic combination operation that FL/UG affords. Put simply, the Merge Hypothesis has (1a-h) as consequences.

Let me say the same thing more tendentiously. All agree that a basic feature of FL/UG is that allows for Gs with unbounded hierarchy. A very simple inductive procedure sufficient for specifying this property (1a), also entails many other features of FL/UG (1b-h). What makes this specification simple is that it directly targets hierarchy and requires that the computation be strongly monotonic (embody the NTC). Thus we can explain the fact that FL/UG has these properties by assuming that it embodies a very simple (arguably, the simplest) version of a procedure that any empirically adequate theory of FL/UG would have to embody. Or, given that FL/UG allows for unbounded hierarchical recursion (a non-controversial fact given the fact of Linguistic Productivity), the simplest (or at least, very simple) version of the requisite procedure brings in its train displacement, an adequate format for semantic interpretation, Reconstruction Effects, movement rules that target c-commanding positions, eschew lowering and are strictly cyclic, and G operations that are structure dependent. Thus, if the Merge Hypothesis is true (i.e. if FL/UG has Merge as the basic syntactic operation), it explains why FL/UG has this bushel of properties. In other words, the Merge Hypothesis, provides a plausible first step in answering the basic MP question: why does FL/UG have the properties it has?

Moreover, it is morally certain that something like Merge will be part of any theory of FL/UG precisely because it is so very simple. It is always possible to add bells and whistles to the G rules FL/UG makes available. But any theory hoping to be empirically adequate will contain at least this much structure. After all, what do (2) and (3) specify? They specify a recursive procedure for building hierarchical structures that does nothing but build such structures. Given the fact of Linguistic Productivity and Linguistic Promiscuity any theory of FL/UG will contain at least this much. If it does not contain much more than this much, then (1a-h) results. Not bad.

---

[1] For example, fans of Dependent Case Theory will reject (1n).

[2] Recall, that LP implies recursion and linguistics has discovered ample evidence that G_Ls can generate structures of arbitrary depth.

[3] The term lexical item denotes the atoms that are not themselves products of Merge. These roughly correspond to the notion morpheme or word, though these notions are themselves terms of art and it is possible that the naïve notions only roughly corresponds to the technical ones. Every theory of syntax postulates the existence of such atoms. Thus, what is debatable is not their existence but their features.

[4] In my opinion, this line of argument does not require that Merge be the “simplest” possible operation. It suffices that it be natural and simple. The conception of Merge in (2) and (3) meets this threshold.

[5] In the best of all worlds, the sole generative procedure.

[6] A phrase marker is just a list of relations that the combined atoms enjoy. Derivations that map phrase markers into phrase markers allow an expression to enjoy different relations coded in the various relations it enjoys in the varying phrase markers.

[7] Copy is simply a descriptive term here. A more technically accurate variant is “occurrence.” b occurs twice in (5b). The logic, however, does not change.

[8] A full theory of REs would articulate the principles behind choosing which copies to interpret. See Sportiche (forthcoming) for an interesting substantive proposal.

[9] Traces within GB are indexed contentless categories: [₁ ec]. 

[10] We could go further: Merge based theory cannot have objects like traces. Traces live on the distinction between Phrase Structure Rules and lexical insertion operations. They are effectively the phrase structure scaffolding without the lexical insertion. But, Merge makes no distinction between structure building and lexical insertion (i.e. between slots and contents). As such, if traces exist, they must be lexical primitives rather than syntactically derived formatives. This would be a very weird conception of traces, inconsistent with the GB rendering in note 12. The same, incidentally, goes for PRO, which we will talk about later on. The upshot: not only would traces violate No tampering, they are indefinable given the “bare phrase structure” nature of movement understood as I-merge.

[11] The first conjunct only holds if there is no inter-arboreal/sidewards movement. For now, let’s assume this to be correct.

[12] For a recent review and defense of the claim see Berwick et. al.

Naturalized philosophy

I went to graduate school in philosophy a long time ago. At that time, there was a premium put on “naturalized” research, the idea being that good philosophy needed grounding in a “real” (non-philosophical) discipline. It was a time when Newton and Einstein and Boyle and Godel and Poincare joined the usual dead white European males that we all know and love in the pantheon of philosophical greats. In this setting, it is no surprise that Chomsky and his work made frequent appearances in the pages of the most prestigious philo journals and was a must read for a philosopher of language. It actually took some effort for the discipline to relegate Chomsky to the domain of “philosophical naïf” (I think this was Putnam’s phrase) and it coincided with endless debates about the implications of the referentialist worldview for narrow content and semantic meaning. IMO, this work did not deliver much in the way of insight, though it did manage to make quite a few careers. At any rate, Chomsky’s exit from the main stage coincided with a waning of the naturalizing project and a return to the metaphysical (and metalinguistic) abstruseness that philosophy is, it appears, endemically attracted to. If nothing else, de-naturalizing philosophy establishes academic protective boundaries providing philosophy with a proprietary subject matter that can protect deep thinkers from the naturalizers and their empirical pretentions.[1] Why do I mention this? Because I am a big fan of the kind of naturalized philosophy that the above mentioned luminaries practiced and so I am usually on the lookout for great examples thereof.

What are the distinctive marks of this kind of work? It generally rests on a few pretty “obvious” empirical premises and demonstrates their fertile implications. Chomsky’s work offers an excellent illustration.

What is Chomsky’s most significant contribution to philosophy (and indeed linguistics)? He identified three problems in need of solution: what does a native speaker know when s/he knows her/his native language? What meta-capacity underlies a native speaker’s capacity to acquire her/his native language? And how did this meta-capacity arise in the species?  These are the big three questions he put on the table. And the subsequent questions they naturally lead to: How do native speakers use their knowledge to produce and understand language, how do LADs use their meta-capacity to acquire their native capacity? How are one’s knowledge of language embodied in wetware?  The last three rely on glimmers of answers to the first three. Chomsky has taught us how to understand the first three. 

Here’s the argument. It is based on few really really really obvious facts. First, that nothing does language like humans do. Birds fly, fish swim, humans do language. It is a species specific capacity unlike anything we find anywhere else. Second, a native speaker displays linguistic creativity. This means that a native speaker can use and understand an unbounded number of linguistic objects never before encountered and does this relatively effortlessly. Third, any kid can reflexively acquire any language when placed in the right linguistic environment (linguistic promiscuity), an environment which, when one looks even moderately closely, vastly underdetermines the knowledge attained (poverty of the linguistic stimulus). These three facts make it morally certain that part of linguistic competence implies internalization of a G, that the human meta-capacity of interest involves a higher order capacity to acquire certain kinds of Gs and not others and that this meta-capacity rests on some distinctive species specific capacities of humans. These three conclusions rest solidly on these obvious facts and together they bring forth a research program: what properties to human Gs have and what is the fine structure of the meta-capacity. That Gs exist and that FL/UG exists is trivially true. What their properties are is anything but.[2]

As FoLers know, Chomsky has recently added a third question to the agenda: how FL/UG could possibly have arisen. He argues that the relative rapidity of the emergence of FL and its subsequent stability argues for an intriguing conclusion: that the change that took place was necessarily pretty small and that whatever is proprietary to language must be quite minor. I tend to think that Chomsky is right about this, and that it motivates a research program that (i) aims to limit what is linguistically special while (ii) demonstrating how this special secret sauce allows for an FL like ours in the context of other more cognitively and computationally general mental capacities it is reasonable to believe that our pre-linguistic ancestors enjoyed. Imo, this line of thinking is less solidly based on “obvious” facts, but the line of inquiry is sufficiently provocative to be very inviting. Again, the details are up for grabs, as they should be.

So what are the marks of naturalized philosophy? Identifying questions motivated by (relatively) straightforward facts that support a framework for asking more detailed questions using conventional modes of empirical inquiry. Chomsky is a master of this kind of thinking. But he is not alone. All of the above is actually in service of advertising another such effort by Randy Gallistel. The paper of interest, which is a marvelous piece of naturalized philosophy appeared here in TiCS. I want to say a word or two about it.

Gallistel’s paper is on the coding question. The claim is that this question has been effectively ignored in the cog-neuro world with baleful effects. The aim is to put it front and center on the research agenda and figure out what kind of neural system is compatible with a reasonable answer to that question. The argument in the paper is roughly as follows.

First, there is overwhelming behavioral evidence that animals (including humans) keeps track of numerical quantities (see box 1, (3)). Hence the brain must have a way to code for number. It must be able to store these numbers in some way and must be able to transmit this stored information in signals in some way. So it must be able to write this information to memory and read this information from memory.

Second, if the brain does code for number it must do so in some code. There are various kinds, but the two the paper discusses are hash/rate/tally codes vs combinatorial codes (4-5). The former are “unary” codes. What this means is that “to convey a particular number one must use as many code elements are the numerosity to which the number refers.” Thus, if the number is 20 then there are 20 hash marks/strokes/dotes whatever representing the number.

The paper distinguishes such codes from “combinatorial” codes. These are the ones we are familiar with. So for example, ‘20’ conveys the number 20 and does so by using 10 digits in order sensitive configurations (i.e. 21 differs from 12). Note, combinatorial code patterns are not isomorphic to the things they represent.[3] 

The paper explores the virtues of combinatorial codes as against hash/rate/tally codes. The latter are “vastly more efficient” by orders of magnitude. Rate codes “convey 1 bit per spike” (5) while it is known that spike trains convey between 3-7 bits per spike. Rate codes are very energy expensive, combinatorial codes can be “exponentially smaller” (6). Last of all, there is evidence that spike trains use combinatorial codes because “reordering the intervals changes the message” (recall ‘21’ vs ‘12’), as expected if they spike trains are expressing a combinatorial code. 

The conclusion: the brain uses a combinatorial code, and this is interesting because this seems to require that the code be “symbolic” in the sense that its abstract (syntactic) structure matters for the information being conveyed.  And this strongly suggests that this info is not stored in synapses as supposed in a neural net system.

This last conclusion should not be controversial. When first put on the market of ideas, neural nets were confidently sold as being non-representational. Rumelhart and McClelland focused on this as one of their more salient properties and Fodor and Pylyshyn criticized such models for precisely this reason. The Gallistel paper is making the additional point that being asymbolic is, in addition to being cognitively problematic, is also neurophysiologically a problem as the kind of codes we are pretty sure we need are the kinds that neural nets are designed not to support. And this means that these are the wrong neuro models for the brain: “In neural net models, plastic synapses are molded by experience” and were intended to model “associative bonds” which “were never conceived of as symbols, and neither are their neurobiological proxies” (8).

Note, we can conclude that neural nets are the wrong model even if we have no idea what the correct model is. We can know what kind of code it is and what this means for the right neurophysiology without knowing what the right neurophysiology is. And if the codes are combinatorial/symbolic then there is no way that the right physiology for memory can be neural nets. This takes the Fodor-Pylyshyn critique on major step further.

So, if not in nets, what kind of architecture. Well, you all know by now. The paper notes that we can get everything we want from a chemical computer. We can physically model classical von Neuman/Turing machines in chemistry, with addresses, reading from, writing to, etc. Moreover, chemical computation has some nice biological features. Complex chemicals can be very stable for long periods of time (what we want from a long term memory store), and writing to such molecules is very energy efficient (8). In addition, chemical computing can be fast (some “can be altered on a nanosecond time scale”) and we know of instances of this kind of chemical computing that are behaviorally relevant. Last chemical computations are very energy efficient. Both storing and computing can be done cheaply if done chemically.

All of this leads to the conclusion that the locus of neurobiological computing is chemical and where are the relevant chemicals? Inside the cell. So, in place of neural nets we have the “cell intrinsic memory hypothesis” (1). Happily, there is now evidence that some computing gets done intra-celluarly (1-2). But if some gets done there…

This paper is great naturalized philosophy: we argue from pretty simple behavioral evidence that a certain kind of coding format is required and then that these kinds of formats prefer certain kinds of physical systems to support such codes and end with conclusions about the locus of the relevant computations. Thus we move from numbers are required, to combinatorial codes are the right kind, to neural nets won’t cut it to chemical computing within the cell. The big open meaty empirical question is what particular combinatorial code is exploited. It’s the cog-neuro analogue of how DNA stores genetic information and uses it. Right now, we do not know. At all.

This last analogy to DNA is important, and, IMO, is the strongest reason for thinking that this line of thinking is correct. Conventional computers provide an excellent model of how computation can be physically implemented. We know how to chemically “build” a conventional computer. We know that biology already uses chemistry to store and use information in hereditary and development. Is it really plausible that this in place machinery is not used for cognitive computation? Or as the paper puts it in the last sentence: “Why should the conveyance of acquired information proceed by principles fundamentally different from those that govern the conveyance of heritable information?” Why indeed! Isn’t the contrary assumption (the machinery is there for the using but it is never used) biologically scandalous? Wouldn’t Darwin be turning in his grave if he considered this? Isn’t assuming it to be false a kind of cognitive creationism? Yup, connetionists and neural net types are the Jerry Falwells of biology! Who would have thunk it: the road from Associationsim to Creationism is paved with Empiricist intentions. Only Rationalism and Naturalized Philosophy can save you.

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[1] Let me quickly add that I consider philosophy training a very useful aid to right thinking. Nothing allows you to acquire the feel for good argumentation than a stressful philosophical workout. And by “good” I mean understanding how premises related to conclusions, how challenging premises can allow one to understand how to evaluate conclusions, understanding that it is always reasonable to ask what would happen to a conclusion should such and such a premise be removed etc.  In other words, philosophy prizes deductive structure and this is a useful talent to nurture regardless of what conclusions you are interested in netting and premises you are interested in frying.

[2] Chomsky, as you all know, not only posed the questions but showed how to go about empirically investigating them. This is what puts him in with the Gods: he discovered interesting questions and figured out technology relevant to answering them.

[3] Thus, the numeral’s patterning represents the number in the former but not the latter. The difference between the two kinds of codes is similar to the one made (here) between patterns that track the patterning and those that do not.

The wildly successful minimalist program

It’s that time of year: spring has sprung, classes are almost over, and all of those commitments you made to write papers three years ago and forgot about are coming due. I am in the midst of one such effort right now (due the end of May). It’s one of those “compare different theories/frameworks” volumes and I have been asked to write on the Minimalist Program (MP). After ignoring the project for a good long time, I initially bridled against the fact that I had accepted to write anything. In order to extricate myself from the promise, I tried to convince the editor that the premise of the volume (that MP was a theory like the others) was false and so a paper on MP would not really be apposite. This tantrum was rejected. I then sulked. Finally, I decided that I would take the bull by the horns and argue that MP, contrary to what I perceive to be the conventional view, has been wildly successful in its own terms and that the reason for its widespread perceived failure is that most critics have refused to accept the premises of MP investigation. Why would they do so? There are several reasons, but the best one (and one that might even be correct) is that the premises for MP investigation (viz. that we know something about the structure of FL/UG and that something resembles GB) are shaky and so the project is premature. On this view the program is fine, it’s just that we’ve gotten a little ahead of ourselves.

This objection should sound familiar. It is what people who study specific languages and their Gs say about claims about FL and UG. We don’t know enough yet about particular Gs to address questions about FL/UG. Things are more complicated and we need time to sort these out.

I reject this. Things are always more complicated. Time is never right. IMO, GB is a pretty good theory and it is worth trying to see if we can derive some of its features in a more principled way. We will learn something even if we are not completely right about this (which is surely the case). In other words, GB is right enough (or, many of its properties will be part of whatever description turns out to be more accurate) and so trying to see how to derive its properties is a worthwhile project that could tech us something about FL/UG.

This, I should add, is the best reason to demur about MP (and as you can see, I am not sympathetic). Two others spring to mind: (i) MP sharpens the linguistics/languistics kulturkampf and (ii) MP privileges a kind of research that is qualitatively different from what most professionals commonly produce and so is suspect. 

I have beaten both these drums in the past, and I do so again here. I have convinced myself that the biggest practical problem for MP work is that it sharpens the contrast between the bio/cog and the philological perspectives on language. More specifically, MP only makes sense from the bio/cog perspective as it takes FL/UG as the object of inquiry. FL/UG is the explanandum. If you don’t think FL/UG exists (or you are not really interested in whether it exists) then MP will seem, at best, pointless and, at worst, mystical omphaloskepsis. It is an odd fact of life that many find their own interests threatened by those that do not share them. I suspect that MP’s greatest sin in the eyes of many is that it appears to devalue their own interest in language by promoting the study of the underlying faculty. This, of course, does not follow. Tastes differ, interests range. But there can be little doubt that one of Chomsky’s many vices is that by convincing so many to be fascinated by the problems he has identified that he has robbed so many of confidence in their own. MP simply sharpens: doing it at all means buying into the bio-cog program. Abandon hope all languists who enter here.

Second, furthering the MP project will privilege a kind of work distinct in style from that normally practiced. If the aim is unification then MP work will necessarily be quite theoretical and the relevance of this kind of work for the kinds of language facts that linguists prize somewhat remote, at least initially. Why? Because if a primary aim of MP is to deduce the basic features of GB from more fundamental principles then a good chunk of the hard work will be to propose such principles and see how to deduce the particular properties of GB from them. The work, in other words, will be analytic and deductive rather than descriptive and inductive. Need I mention again how little our community of scholars esteems such work?

I we put these two features of MP inquiry together, we end up with work that is hard core bio-mentalist and heavily deductive and theoretical in nature. Each feature suffices to generate skepticism (if not contempt) among many working linguists. This, at any rate, is what I argue in the paper that I avoided trying to write.

I cannot post the whole thing (or at least won’t do so today). But I am going to given you the intro stage setting (i.e. polemical) bits for your amusement.  Here goes, and may you have a happy time with your own thoughtless commitments.

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What is linguistics about? What is its subject matter? Here are two views.

One standard answer is “language.” Call this the “languistic (LANG) perspective.” Languists understand the aim of a theory of grammar to describe the properties of different languages and identify the common properties they share. Languists frequently observe that there are very few properties that all languages have in common. Indeed, in my experience, the LANG view is that there are almost no language universals that hold without exception and that languages can and do vary arbitrarily and limitlessly. LANGers assume that if there are universals, then they are of the Greenbergian variety, more often statistical tendencies than categorical absolutes.  

There is a second answer to the question, one associated with Chomsky and the tradition in Generative Grammar (GG) his work initiated. Call this the linguistic (LING) perspective.” Until very recently, linguists have understood grammatical theory to have a pair of related objectives: (i) to describe the mental capacities of a native speaker of a particular language L (e.g. English) and (ii) to describe the meta-capacity that allows any human to acquire the mental capacities underlying a native speaker facility in a particular L (i.e. the meta-capacity required to acquire a particular G). LINGers, in other words, take the object of study to be two kinds of mental states, one that grammars of particular languages (i.e. G_L) describe and one that “Universal Grammar” (UG) describes. UG, then, names not Greenbergian generalizations about languages but features of human mental capacity that enable them to acquire G_Ls. For linguists, the study of languages and their intricate properties is useful exactly to the degree that it sheds light on both of these mental capacities. As luck would have it, studying the products of these mental capacities (both at the G and UG level) provides a good window on these capacities.

The LANG vs LING perspectives lead to different research programs based on different ontological assumptions. LANGers take language to be primary and grammar secondary. G_Ls are (at best) generalizations over regularities found in a language (often a more or less extensive corpus or lists of “grammaticality” judgments serving as proxy).[1] For LINGers, G_Ls are more real than the linguistic objects they generate, the latter being an accidental sampling from an effectively infinite set of possible legitimate objects.[2] On this view, the aim of a theory of a G_L is, in the first instance, to describe the actual mental state of a native speaker of L and thereby to indirectly circumscribe the possible legit objects of L. So for LINGers, the mental state comes first (it is more ontologically basic), the linguistic objects are its products and the etiology of those that publically arise (are elicited in some way) only partially reflect the more stable, real, underlying mental capacity. Put another way, the products are interaction effects of various capacities and the visible products of these capacities are the combination of their adventitious complex interaction. So the products are “accidental” in a way that the underlying capacities are not.

LANGers disagree. For them the linguistic objects (be they judgments, corpora, reaction times) come first, G_Ls being inductions or “smoothed” summaries of these more basic data. For LINGers the relation of a G_L to its products is like the relation between a function and its values. For a LANGer it is more like the relation between a scatter plot and the smoothed distributions that approximate it (e.g. a normal distribution).

LINGers go further: even G_Ls are not that real. They are less real than UG, the meta-capacity that allows humans to acquire G_Ls. Why is UG more “real” than G_Ls? Because in a sense that we all understand, native speakers only accidentally speak the language they are native in. Basically, it is a truism universally acknowledged that any kid could have been native in any language. If this is true (and it is, really), then the fact that a particular person is natively proficient in a particular language is a historical accident. Indeed, just like the visible products of a G_L result from a complex interaction of many more basic sub-capacities, a particular individual’s G_L is also the product of many interacting mental modules (memory size, attention, the particular data mix a child is exposed to and “ingests,” socio-economic status, the number of hugs and more). In this sense, every G_L is the product of a combination of accidental factors and adventitious associated capacities and the meta-capacity for building G_Ls that humans as a species come equipped with.

If this is right, then there is no principled explanation for why it is that Norbert Hornstein (NH) is a linguistically competent speaker of Montreal English. He just happened to grow up on the West Island of that great metropolis. Had NH grown up in the East End of London he would have been natively proficient in another “dialect” of English and had NH been raised in Beijing then he would have been natively proficient in Mandarin. In this very clear sense, then, NH is only accidentally a native speaker of the language he actually speaks (i.e. has acquired the particular grammatical sense (i.e. G_L) he actually has) though it is no accident that he speaks some native language. At least not a biological accident for NH is the type of animal that would acquire some G_L as a normal matter of course (e.g. absent pathological conditions) if not raised in feral isolation. Thus, NH is a native speaker of some language as a matter of biological necessity. NH comes equipped with a meta-capacity to acquire G_Ls in virtue of the fact that he is human and it is biologically endemic to humans to have this meta-capacity. If we call this meta-capacity the Faculty of Language (FL), then humans necessarily have an FL and necessarily have UG, as the latter is just a description of FL’s properties. Thus, what is most real about language is that any human can acquire the G_L of any L as easily as it can acquire any other. A fundamental aim of linguistic theory is to explain how this is possible by describing the fine structure of the meta-capacity (i.e. by outlining a detailed description of FL’s UG properties).

Before moving on, it is worth observing that despite their different interests LINGers and LANGers can co-exist (and have co-existed) quite happily and they can fruitfully interact on many different projects. The default assumption among LINGers is that currently the best way to study G_Ls is to study its products as they are used/queried. Thus, a very useful way of limning the fine structure of a particular G_L is to study the expressions of these G_Ls. In fact, currently, some of the best evidence concerning G_Ls comes from how native speakers use G_Ls to produce, parse and judge linguistic artifacts (e.g. sentences). Thus, LINGers, like LANGers, will be interested in what native speakers say and what they say about what they say. This will be a common focus of interest and cross talk can be productive.

Similarly, seeing how G_Ls vary can also inform one’s views about the fine structure of FL/UG. Thus both LINGers and LANGers will be interested in comparing G_Ls to see what, if any, commonalities they enjoy. There may be important differences in how LINGers and LANGers approach the study of these commonalities, but at least in principle, the subject matter can be shard to the benefit of each. And, as a matter of fact, until the Minimalist Program (MP) arose, carefully distinguishing LINGer interests from LANGer interests was not particularly pressing. The psychologically and philologically inclined could happily live side by side pursuing different but (often enough) closely related projects. What LANGers understood to be facts about language(s), LINGers interpreted as facts about G_Ls and/or FL/UG.

MP adversely affects this pleasant commensalism. The strains that MP exerts on this happy LING/LANG co-existence is one reason, I believe, why so many GGers have taken a dislike to MP.  Let me explain what I mean by discussing what the MP research question is. For that I will need a little bit of a running start.

Prior to MP, LING addressed two questions based on two evident rationally uncontestable facts (and, from what I can tell, these facts have not been contested). The first fact is that a native speaker’s capacities cover an unbounded domain of linguistic objects (phrases, sentences etc.). Following Chomsky (1964) we can dub this fact “Linguistic Creativity” (LC).[3]  dI’ve already adverted to the second fact: any child can acquire any G_L as easily as any other. Let’s dub this fact “Linguistic Promiscuity” (LP). Part of a LINGers account for LC postulates that native speakers have internalized a G_L. G_Ls consist of generative procedures (recursive rules) that allow for the creation of unboundedly complex linguistic expressions (which partly explains how a native speaker effortlessly deals with the novel linguistic objects s/he regularly produces and encounters).

LINGers account for the second fact, LP, in terms of the UG features of FL.  This too is a partial account. UG delineates the limits of a possible G_L. Among the possible G_Ls, the child builds an actual one in response to the linguistic data it encounters and that it takes in (i.e the Primary Linguistic Data (PLD)).

So two facts, defining two questions and two kinds of theories, one delimiting the range of possible linguistic expressions for a given language (viz. G_Ls) and the other delimiting the range of possible G_Ls (viz. FL/UG). As should be evident, as a practical matter, in addressing LP it is useful to have to hand candidate generative procedures of specific G_Ls. Let me emphasize this: though it is morally certain that humans come equipped with a FL and build G_Ls it is an empirical question what properties these G_Ls have and what the fine structure of FL/UG is. In other words, that there is an FL/UG and that it yields G_Ls is not really open for rational debate. What is open for a lot of discussion and is a very hard question is exactly what features these mental objects have. Over the last 60 years GG has made considerable progress in discovering the properties of particular G_Ls and has reasonable outlines of the overall architecture of FL/UG. At least this is what LINGers believe, I among them. And just as the success in outlining (some) of the core features of particular Gs laid the ground for discovering non-trivial features of FL/UG, so the success in liming (some of) the basic characteristics of FL/UG has prepared the ground for yet one more question: why do we have the FL/UG that we have and not some other? This is the MP question. It is a question about possible FL/UGs.

There are several things worth noting about this question. First, the target of explanation is FL/UG and the principles that describe it. Thus, MP only makes sense qua program of inquiry if we assume that we know some things about FL/UG. If nothing is known, then the question is premature. In fact, even if something is known, it might be premature. I return to this anon. 

Second, the MP question is specifically about the structure of FL/UG. Thus, unlike earlier work where discussions of languistic interest can be used to obliquely address LC and LP, the MP question only makes sense from a LING perspective. It is asking about possible FL/UGs and this requires taking a mentalistic stance. Discussing languages and their various properties had better bottom out in some claim about FL/UG’s limits if it is to be of MP relevance.  This means that the kind of research MP fosters will often have a different focus from that which has come before. This will lead LANGers and LINGers to a more obvious parting of the investigative ways. In fact, given that MP takes as more or less given what linguists and languists have heretofore investigated as basic, MP is not really an alternative to earlier theory. More specifically, MP can’t be an alternative to GB because, at least initially, MP is a consumer of GB results.[4] What does this mean?

An analogy might help. Think of the relationship between thermodynamics and statistical mechanics. The laws of thermodynamics are grist for the stats mechanics mill, the aim being to derive the thermodynamic generalizations in a more principled atomic theory of mechanics. The right way to think of MP and early theory is in the same way. Take (e.g.) GB principles and see if they can be derived in a more principled way. That’s one way of understanding the MP program, and I will elaborate this perspective in what follows. Note, if this is right, then just as many thermodynamical accounts of, say, gas behavior will be preserved in a reasonable statistical mechanics, so too many GB accounts will be preserved in a decent MP theory of FL. The relation between GB and MP is not that between a true theory and a false one, but a descriptive theory (what physicists call an “effective” theory) and a more fundamental one.

If this is right, then GB (or whatever FL/UG is presupposed) accounts will mostly be preserved in MP reconstructions. And this is a very good thing! Indeed, this is precisely what we expect in science; results of past investigations are preserved in later ones with earlier work preparing the ground for deeper questions. Why are they preserved? Because they are roughly correct and thus not mimicking these results (at least approximately) is excellent indication that the subsuming proposal is off on the wrong track. Thus, a sign that the more fundamental proposal is worth taking seriously is that it recapitulates earlier results and thus a reasonable initial goal of inquiry is to explicitly aim to redo what has been done before (hopefully, in a more principled fashion).

If this is correct, it should be evident why many might dismiss MP inquiry. First, it takes as true what many will think contentious and tries to derive it. Second, it doesn’t aim to do much more than derive “what we already know” and so does not appear to add much to our basic knowledge, except, perhaps, a long labored (formally involved) deduction of a long recognized fact.

Speaking personally, my own work takes GB as a roughly correct description of FL/UG. Many who work on refining UGish generalizations will consider this tendentious. So be it. Let it be stipulated that at any time in any inquiry things are more complicated than they are taken to be. It is also always possible that we (viz. GB) got things entirely wrong. The question is not whether this is an option. Of course it is. The question is how seriously we should take this truism.

So, MP starts from the assumption that we have a fairly accurate picture of some of the central features of FL and considers it fruitful to inquire as to why we have found these features. In other words, MP assumes that time is ripe to ask more fundamental questions because we have reasonable answers to less fundamental questions. If you don’t believe this then MP inquiry is not wrong but footling.

Many who are disappointed in MP don’t actually ask if MP has failed on its own terms, given its own assumptions. Rather it challenges the assumptions. It takes MP to be not so much false as premature. It takes issue with the idea that we know enough about FL/UG to even ask the MP question. I believe that these objections are misplaced. In other words, I will assume that GBish descriptions of FL/UG are adequate enough (i.e. are right enough) to start asking the MP question. If you don’t buy this, MP will not be to your taste and you might be tempted to judge its success in terms of your interests rather than its own questions.

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[1] There are few more misleading terms in the field than “grammaticality judgment.” The “raw” data are better termed “acceptability” judgments. Native speakers can reliably rank linguistic objects with regard to relative acceptability (sometimes under an interpretation). These acceptability judgments are, in turn, partial reflections of grammatical competence. This is the official LING view. LANGers need not be as fussy, though they too must distinguish data reflecting judgments in reflective equilibrium from more haphazard reactions. The reason that LANGers differ from LINGers in this regard reflects their different views on what they are studying. I leave it to the reader to run the logic for him/herself.

[2] The term set should not be taken too seriously. There is little reason to think that languages are sets with clear in/out conditions or that objects that G_Ls generate are usefully thought of as demarcating the boundaries of a language. In fact, LINGers don’t assume that the notion of a language is clear or well conceived. What LINGers do assume is that native speakers have a sense of what kinds of objects their native capacities extend to and that this is an open ended (effectively infinite) capacity and that is (indirectly) manifest in their linguistic behavior (production and understanding) of linguistic objects.

[3] Here’s Chomsky’s description of this fact in his (1964:7):

…a mature native speaker can produce a new sentence of his language on the appropriate occasion, and other speakers can understand it immediately, though it is equally new to them. Most of our linguistic experience, both as speakers and hearers, is with new sentences; once we have mastered a language, the class of sentences with which we can operate fluently is so vast that for all practical purposes (and, obviously, for all theoretical purposes), we may regard it as infinite.

 [4] Personally, I am a big fan of GB and what it has wrought. But MP style investigations need not take GB as the starting point for minimalist investigations. Any conception of FL/UG will do (e.g. HPSG, RG, LFG etc.). In my opinion, the purported differences among these “frameworks” (something that this edited collection highlights) have been overhyped. To my eye, they say more or less the same things, identify more or less the same limiting conditions and do so in more or less the same ways. In other words, these differing frameworks are largely notational variants of one another, a point that Stabler 2010) makes as well.