feature structures vs. feature structure descriptions

[Lutz Gunkel]

All,

I have some questions on the relation between feature structures and
feature structure descriptions in HPSG. As I see it, feature structures
belong to the object language, feature structure descriptions to the
metalanguage, the language the theory/grammar *uses*. As such, feature
structure desctiptions by definition are not entities the theory/grammar
talks about or refers to, it just uses them to talk about feature structures.

However, in some HPSG (related) work it appears that it is just feature
structure descriptions the theory/grammar talks about. For example, in the
new book by Sag and Wasow, the authors start out saying that

''It is just the goal of a grammar to enumerate all these linguistic
entities [...] and to correctly describe their grammatical properties." (p.
63)

(Note that ''linguistic entities'' refers to entities of the object
language.) In what follows we then find statements like:

"Second, we characterize how descriptions of smaller structures (words or
phrases) get amalgamated into descriptions of larger structures, including
sentences." (p.63)

In fact, what Sag and Wasow are doing here (and on the following page) is
defining a metalanguage. This, it is true, has to be done somewhere, at
least if the metalanguage is a formal one. But what is important is that
all important grammatical generalizations appear to be part of the
*definition* of the metalanguage (thus they appear to be part of a
meta-metalanguage). They are not about feature structures (and trees) but
rather about feature structure descriptions (or tree descriptions), compare:

"And finally the new tree description has to satisfy all the principles of
our theory [...]''. (p.64)

In contrast, I think it is reasonable and desirable that grammatical
generalizations belong the metalanguage, thus being theorems about the
object language.

I hope that somebody can help me sorting out these confusing issues. Thanks.

Lutz


@Unpublished{    Sag:Wasow:97,
  author = 	 {Ivan A. Sag and Thomas Wasow},
  title = 	 {Syntactic Theory. {A} Formal Introduction. {F}inal Draft of
September 1997},
  note =         {Unpublished Manuscript. Stanford University},
  year = 	 {1997}
}