theory and formalism in LFG: too much inertia? (long msg)

[Yehuda N. Falk]

A somewhat belated response to Joan's post.

Joan, in responding to my plea for some discussion on what is ostensibly a
discussion list, asked whether extension and enrichment of the LFG
formalism ought to be a top priority. First a caveat.

>I hesitate to start another discussion of the philosophy of science,
>which linguists, in their naive scientism, are generally so boring
>about.

I have never imagined myself to be particularly skilled in discussing
philosophy of anything, so I may turn out to be boring. But I'll give it a
whirl.

>LFG has separated its very powerful formalism (which lets us describe
>many phenomena, natural and unnatural) from the various substantive
>theories of argument realization, phrase structure typology, etc.,
>which attempt to explain the limited typological ranges found in
>natural languages.  The latter have generally been treated as
>metatheories, and have seldom been incorporated into the formal
>architecture.  This means that formalization has lagged behind the
>development of substantive theories.  From the engineering standpoint,
>the inertia of the formalism has been valued.  But from the standpoint of
>cognitive theory, I wonder, Is this a good thing?
>
>[snip]
>But we are living in dynamic times,
>cognitively speaking: the old MIT-style generative epistemology which
>held sway when LFG was invented is being overtaken by alien concepts
>such as optimization, probability, comparative grammaticality,
>markedness, and the like.  These are turning out to have interesting
>consequences for explaining typologies.  This suggests that we
>need to put more effort into enriching and expanding our formal
>architectures as a top priority, no?

I think Joan is essentially correct. We need to be careful to distinguish
"enriching and expanding" the formalism from completely changing it, as
some other linguistic theories do from time to time. The LFG formalism was
designed to capture the idea that certain concepts, such as correspondence
between elements at different levels of representation, are crucial
elements of linguistic description, while others, like movement, are not.
The formalism was also designed with computational simplicity in mind. To a
large extent, I think the LFG formalism has vindicated itself. Any
revamping of the formal system must keep these basic ideas in place. The
change should be evolutionary, not revolutionary.

On the other hand, as Joan points out, our understanding of the nature of
language and grammar are undergoing massive change as generative grammar
matures and allows itself to consider "alien concepts such as optimization,
probability, comparative grammaticality, markedness, and the like [which]
are turning out to have interesting consequences for explaining
typologies." As Joan points out,

>There is of course a relation between formal architecture and
>substantive explanation: for example, some architectures may be
>incapable of allowing you to express important empirically motivated
>generalizations.

The fact is that the current LFG formalism does not always allow the
expression of markedness- (or whatever-) based generalizations. This is an
indication that the formalism does need to be enriched. But there is also a
side to this that Joan didn't mention: a formalism can also allow us to put
constraints on what is a possible substantive linguistic constraint.
[WARNING: The following was written by someone who is skeptical about OT]
For example, it seems to me that there are no restrictions on what can be a
possible OT-LFG constraint. Somehow, the architecture of a linguistic
theory needs to put constraints on what is a possible constraint.

It is also true that the place of OT, probability, etc. in LFG (or any
formal linguistic theory) is still up for grabs. We do not know the full
extent of these elements or how they interact with the rule and
representational systems that we all know and love. But starting to toy
around with formalisms that will allow us to model some of these
interactions may provide us with some answers.



                             Yehuda N. Falk
                        (until 4 February 2000:)
             Department of Linguistics, Stanford University
                        Stanford, California, USA
                             (permanent:)
        Department of English, The Hebrew University of Jerusalem
                      Mt. Scopus, Jerusalem, Israel

                         msyfalk at mscc.huji.ac.il
            until 4 February also: yfalk at leland.stanford.edu
       Personal Web Site    http://pluto.mscc.huji.ac.il/~msyfalk/
      Departmental Web Site    http://atar.mscc.huji.ac.il/~english/

"And because,  in all the galaxy, they had found  nothing more precious than
Mind,  they  encouraged  its dawning everywhere.  They became farmers in the
fields of stars; they sowed, and sometimes they reaped." --Arthur C. Clarke,
2001: A Space Odyssey