Re: Ontology for EDI (was Frames...) (Pat Hayes)
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Date: Fri, 23 Sep 1994 15:54:47 +0000
To: "Peter Clark" <>,
From: (Pat Hayes)
Subject: Re: Ontology for EDI (was Frames...)
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At  2:04 PM 9/22/94 -0500, Peter Clark wrote:
>Pat Hayes writes...
>> Is a fitted carpet IN a room or PART OF the room? How about the paint 
>> on the wall? How can I write axioms (or something) which say, "I don't car
>> about this issue", without either saying nothing, or using impossibly
>> large disjunctions?
>Well, are the disjunctions so large? It seems that you are wanting to 
>work at a more abstract level, using (and axiomitizing) more abstract
>relations eg. InOrPartOf ("FixtureOf" say) to describe the
>relation between a room and a carpet. The large disjunctions only
>come in when you try to push the level of detail, and expand
>the abstract description into a more detailed version (which
>specifies whether the carpet is IN or PART-OF the room). But if you 
>don't really care whether the carpet's IN or PART-OF, then there's no 
>reason to push down to this level and those "impossibly large disjunctions"
>could be avoided.
> I don't see why you feel "forced" to work
>at the IN and PART-OF level if you don't care about it. 

Well,maybe. But I find again and again that I get caught between two hard
places. In order to get some conclusions I want - for example, the
transitivity of IN, or that going IN involves somehow passing through the
boundary - I need to write enough about the concept that I am then forced
to take a stance on issues like whether the carpet is IN or not. If this
were just an occassional difficulty, then thats life; but it seems to be
pervasive, and its this fact - that this seems to happen again and again -
that makes me think it maybe has something to do with an inadequacy in the
tools I am using.

Of course it is possible to make vaguer concepts, but the tension then lies
in not making them so vague that its hard to say anything useful with them.

Look, I agree with you: we have to choose levels of precision and the
choice is sensitive, and so forth. But its damned hard to get it right. I
only meant to suggest that this snag seemed to happen again and again, and
to wonder if it might not be a symptom of a deeper problem. Perhaps we need
to cut up the conceptual space in ways that our logics can't cut.

Best wishes


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