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Date:         Mon, 9 Nov 1992 16:31:23 PST
From:         Penni Sibun <sibun@PARC.XEROX.COM>
Subject:      Re: Marking and models
              9 Nov 1992 10:44:46 -0800 <92Nov9.130140pst.11863@alpha.xerox.com>

(penni sibun 921109.1700)

    [From Bill Powers (921109.1100)]

    Avery Andrews (921109) --

    Your comments on "marking" plus some by Hank Folson and Dag Forssell
    have brought my feeling of "something missing" into sharper focus.
    What's missing in linguistics is a model.

    When you talk about marking things in the knowledge base as said or
    not said, you're IMPLYING a model without saying what it is.

i think this discussion of marking is a serious sidetrack.  the
already-said? mechanism was basically a kludge to allow me to complete
my thesis in finite time.  i actually think redundacy is fascinating
(it happens all the time) but it wasn't my focus.  i have a friend in
computational linguistics who is doing a thesis on just a class of
redundancies (and i may be able to incorporate her work into salix).

in any event, here's all that already-said? ever claimed to do
(Locally Organized Text Generation. COINS Technical Report 91-73,
Department of Computer and Information Science, University of
Massachusetts, 1991.  Also Report SSL-91-21/P91-00159, Xerox Palo Alto
Research Center, 1991, p. 41) (``{\em'' indicates emphasized text):

  Each object [in the KB] has an {\em already-said?} field.  This field is
  initialized to {\em nil}; when an object has been explicitly mentioned
  in the text, this field is set to {\em t}.  The strategies which find
  something to say next will not be triggered by an object that is {\em
  already-said?}.  An object which is {\em already-said?} may be
  mentioned again, but only in relation to another object.  For example,
  in the following text:

  (1) there's Penni
  (2) and then there's Barbara
  (3) who is Penni's sister

  In (1), Penni is explicitly mentioned, and marked as {\em
  already-said?}; in (3) she is mentioned in passing, in relation to
  Barbara.


    The reason I asked about the nature of the knowledge base and how
    marking might be accomplished is that I was trying to get at your
    underlying model. What, literally, is the form of the knowledge base
    in a human being?

i'm not even sure that there's a kb-analog in the brain; i bet there
is no ``marking.''

    can see what its other implications are (other than serving the
    immediate purpose of explaining how we know something has been said).

``marking'' doesn't have explanatory power.  it's a mechanism (and a
kludgy one at that, as i said).  again, we seem to be getting a
conflation of programs and theories.

    But most phenomena seem at first to be outside the
    model only because we're already interpreting them in terms of a
    different model. "Marking" is an example. Behind that interpretation
    are images of the way we would use a pencil-and-paper checklist. But
    that image is inadequate, because it implies operations and
    perceptions that are not in the model -- and that are not plausible
    additions to the model.

sigh.  right.  that's why i'm sorry you got that extra-model
interpretation and hope everyone drops it!!  the ``checklist model''
is not my creation; it's not in *my* thesis!

cheers.

				--penni