On communicating with others about the SMT post (here) I
have come to believe that it can be used to illustrate what I find unfortunate
about a Platonist conception of linguistics. So with the sincere desire of
afflicting the platonistically comfortable, I would like to outline how the
version of the SMT I discussed earlier makes relatively little sense from a
Platonist perspective. Moreover, given the demonstrated empirical fecundity of
this kind of SMT research, so much the worse for a Platonist conception. In
other words, any conception of linguistics that insulates itself from these
kinds of considerations is one to be shunned, dumped, dispensed with, thrown
onto the garbage heap of very bad ideas. Strong words, eh? Good, that was my
intent. Let me elaborate.
The previous post suggested that an excellent way of
understanding the SMT is in terms of the degree of transparency holding between
linguistic representations and those exploited by the interfaces to do whatever
they do. Pietroski, Lidz, Halberda and Hunter
(PLHH) argue that the right linguistic representation for the meaning of most concerns quite a bit more than
getting the truth conditions right. It
also includes getting a decent account of how these representations are
deployed to “count.” The argument proceeds as follows: They observe that there
are many distinct ways of presenting the truth conditions and that some are
more congenial to the ANS+visual system than others in in being favored by ANS+visual
interface when it evaluates sentences like Most
of the dots are blue when presented with various dot arrays. Specifically,
they demonstrate that subjects evaluate the truth of such sentences in such
scenes by applying the operations and predicates explicitly represented in (1c),
not those in the truth functionally equivalent (1a,b). Indeed, they show that
representations like (1a,b) are shunned even when they could have been
effectively used.[1]
(1) a. OneToOnePlus*: [{x: D
(x)}, [x: Y
(x)}] iff some some set s, s Ì {X: D
(x)} and OneToOne [s, {x: Y
(x)}]
b.
|{x: D
(x) & Y
(x)}| > {x: D
(x) & - Y
(x)}|
c.
|{x: D
(x) & Y
(x)}| > |{ x: D
(x)}| - |{x: D(x)
& Y
(x)}|
What’s this mean? Well, given that these three
representations are truth functionally identical they must support all the same
inferences. So looking at standard
linguistic data (e.g. what inferences each supports) fails to choose between
them. However as they get to these same truth conditions in different ways
(i.e. using different predicates and operations) then if you assume that the
interfaces use the representations provided by L to do what they do (i.e. the
SMT), then not all truth functionally equivalent representations of most need be empirically equal. Why not?
Because some (e.g. (1c)) might explain how humans judge visual displays while
the others (e.g. (1a,b)) do not. In other words, as the ANS+visual system
evaluates sentences like most of the dots
are blue by comparing the size of the set of blue dots and the size of the
set of all the dots minus the blue dots (i.e. by using the information as
depicted in (1c)) this argues for (1c) being the correct representation of the meaning of most. More interesting
still, PLHH show that if we assume that it is a design feature of linguistic
representations that they perfectly cater to the needs of the interfaces (viz.
the SMT understood in terms of transparency) we can explain why (1c) has some of the properties it
does (hint: because the interfaces are capable of doing some things well and
not others).[2]
Now, I really like this argument form. It provides a way
of unpacking the SMT in terms of the Transparency Thesis. It is able to
generate rich non-trivial hypotheses about linguistic representations that are
susceptible to empirical testing (as PLHH demonstrate). However, and here is the punchline, none of
this makes much sense from a Platonist perspective. Why? Because it presupposes
that linguistic representations can be investigated by considering how they fit
with other features of human cognition. More specifically, it assumes that we
can learn something about linguistic
structures by investigating how they are used by other human mental organs (here,
the ANS+visual system). Or to put this
another way, entailment relations and judgments of truth conditions do not
exhaust the evidence relevant to discovering the properties of linguistic representations. As
PLHH demonstrate, how humans verify these truth conditions (i.e. how the
products of FL interact with performance-interface systems) is relevant as
well. But this only makes sense if these representations are psychologically
active, i.e. they don’t live in some disembodied platonic heaven. Put crudely,
though competence is not the same as performance, on my view of linguistics
(and PLHH’s and Berwick and Weinberg’s and Colin Phillips’ and Poeppel’s and (I
believe) Chomsky’s, in fact in all those with a reasonable view of scientific
practice) it is possible to learn about the structure of competence grammars
(i.e. about how sentences are represented mentally) by looking at how they are
put to use. Some (e.g. the later Katz[3])
seem to have concluded from the fact that this is hard to do and that many
peaks at the interface fail to reveal anything interesting that this is in principle impossible. This is a very counter-productive view to
take. And, talking methodology, this is the strongest kind of criticism one can
level against a proposed conception. Bluntly, Platonism is a bad position to adopt for it blinkers your
investigative options by precluding certain questions from consideration.
I mentioned a while ago (here) that one thing that I don’t
like about the Platonic Attitude is that it serves to confine linguistic
investigation to its own little empirical ghetto. Roughly “grammaticality”
judgments count, entailments ok, ditto, synonymy and paraphrase. However, no
psycho evidence please: what kids do in acquiring their grammar, or how people
parse sentences or how dot displays are evaluated are not relevant to
linguistics proper. This latter kind of data is in principle incapable of probing linguistic representations. Sure,
once linguists have done their work, we can ask how their constructs might be
used. But, only linguistic evidence
is relevant in evaluating linguistic
structure, psycho, bio and neuro evidence is in principle besides the point.
What the work on most (and the other
stuff discussed in the previous post) shows is that this attitude cuts research
off from a bevy of interesting questions and investigations. Of course, one can take a cramped view of linguistic
research, but, really, why do it? Why
cleave to a view that imposes blinders on research? Why draw metaphysical lines
in the sand that hinder investigation?
My conclusion: not only are there no good arguments against the mentalist conception of grammar and the cog-bio
conception of linguistics but there are good methodological reasons to reject Platonism in this domain. One
cannot stop people from choosing a cramped scientific aesthetic if this is
where they are determined to go, but there are good reasons of scientific
hygiene to shun this step. Consider yourself duly warned!
[1]
Recall, here could have been means
that the interface has the power to apply the relevant information in (1a,b)
(i.e. they present evidence that in other contexts it does so) and it would be
a very good (viz. optimal) strategy to
do so in some of the arrays presented.
So, logically speaking, all three of the alternatives could have been on an equal footing, circumstances choosing between them
This, however, turned out to be false, and that is very very interesting.
[2]
I confess that I am not sure that I believe that this is a reasonable metaphysical assumption, though it is an
excellent methodological principle. Thus, it works well as a directive for
exploring the properties of linguistic representations. However, I find it
harder to see how the interfaces could cause
FL to have the properties it has. Darwin and his buddies could in principle be
useful here, were it not for the fact that the time apparently available seems
pretty short, hence not leaving much room for natural selection to work its
magic. For now, I am putting these sophistications aside. Maybe I’ll post more
on this later. Be warned!
[3]
In fact, the early Katz (he of Katz and Fodor 1963 (“The structure of semantic
theory” in Language)) had the more
expansive conception outlined here. Someone who might know (p.c.) speculates
that the “failure” to empirically ground the derivational theory of complexity
is what led Katz to throw in the towel and retreat to Platonism. Too bad. But
unlike some later epigones, at least Katz had it right the first time.
