From: Lillie Kittredge (kittredl_at_u.washington.edu)
Date: Wed Oct 22 2003 - 10:18:07 PDT
Lillie Kittredge
Review:
John Doyle, Ramesh Patil, "Two theses of knowledge representation"
This paper argued against a proposed restricted scheme of knowledge
representation, and made some motions towards outlining a nonrestrictive
scheme.
The main points of the paper were the argument against the restrictive
scheme:
1. Restricting languages by ommitting some constructs "destroys the
generality of the language". That is, there are definable concepts that
become inexpressible. Since some of these concepts, explained in great
length in section2 of the paper, are necessary to some applications,
this is unacceptable.
2. A fully expressive language, however, must include some of the
constructions that the creators of the restricted lanaguage were trying
to avoid, specifically the ones which require non-poynomial worst-case
response time. Though Doyle and Patil point out that worst-case time is
not always an appropriate metric, they acknowledge that there must be
a tradeoff between expressiveness and completity, and that because of
this tradeoff, there can be no general purpose langauge.
I felt that the largest flaw of this paper was that it really was not
clear about what an alternative, non-restrictive knowledge
representation would consist of. Given that almost all of the paper is
devoted to tearing down the restrictive scheme, I'd be a lot more
impressed if they presented a clearer view of an alternative. As it is,
they just say what principles should be important in designing one.
Also, it was _way_ too wordy.
Open questions: What would an unrestricted representation look like?
How would they actually implement all their ideas about what properties
it should have? One might also try to classify the systems in which the
restrticted version would work; ones which do not require the assortment
of defenitions outlined in the paper's section 2 which are inexpressible
in the restricted version-- what systems can make do without those, and
would they really benefit in performance from the restricted
representation?
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