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Re: context (comments on http://www.w3.org/TR/2002/WD-rdf-schema-20021112/)

From: Richard H. McCullough <rhm@cdepot.net>
Date: Tue, 3 Dec 2002 13:03:15 -0800
Message-ID: <002001c29b0f$6664ec20$bd7ba8c0@rhm8200>
To: "pat hayes" <phayes@ai.uwf.edu>
Cc: "Brian McBride" <bwm@hplb.hpl.hp.com>, <www-rdf-comments@w3.org>
Re: context (comments on http://www.w3.org/TR/2002/I have consistently used the same definition of context (http://rhm.cdepot.net/doc/KEtutorial.txt)
    space = where action occurs
+  time = when action occurs
+  view = proposition list which captures prior knowledge

Depending of the context of the discussion, I sometimes emphasized one of space/time/view, 
but my definition has not changed.

I am fully aware that others do not agree on a definition of context.  You and I attended the same 
Context Symposium at MIT in 1997.
Dick McCullough 
knowledge := man do identify od existent done
knowledge haspart proposition list

  ----- Original Message ----- 
  From: pat hayes 
  To: Richard H. McCullough 
  Cc: Brian McBride ; www-rdf-comments@w3.org 
  Sent: Tuesday, December 03, 2002 12:39 PM
  Subject: Re: context (comments on http://www.w3.org/TR/2002/WD-rdf-schema-20021112/)

    Just two quick comments on context -- stimulated by your previous comments on context.

    1. Context is always important. 

  I might take that comment seriously if I knew what it meant.

    Here's a trivial example.
            Dick McCullough is married.
    In the context of December 2002, this statement is false. 
    In the context of any time between June 1960 and September 1996, it's true.

  No. It was true AT one time but not AT another; or, it was true OF one time but not OF another; or, it is incompletely specified as stated and hence neither true not false, but rather something like a predicate which applies to temporally located entities.

    Here's another example.
            Names denote things in the universe, and sets of triples denote truth-values.
    which is true in the context of your document http://www.w3.org/TR/2002/WD-rdf-mt-20021112/
    but is false in the context of my document http://rhm.cdepot.net/doc/KEtutorial.txt.

  Documents are not contexts in your first sense, and truth is not defined with respect to documents in any case.

    2. Knowledge is advanced by integrating facts into a wider context. 
    For example, in physics,
            force = mass x acceleration
    is a principle which integrates observed facts from many different contexts into a single context. 

  Nonsense. Cite me any physics textbook which refers to such a notion of 'context'.

    By expanding that context to include variable mass and acceleration, we get a broader principle
            force = rate of change of momentum

  Your message illustrates the central problem with the word 'context': it means everything, and so it means nothing. You use it above in three distinct senses which have got nothing whatever to do with one another, and it has been used to mean anything from a single token of a phrase in a particular utterance to an entire culture or human epoch. I have been to maybe six or seven workshops, colloquia, etc., on the topic of 'context' and I don't think I have yet heard two people agree on a definition of the word. On one memorable occasion I listened to talks every hour for 3 working days, and kept careful records, and NONE of them agreed with ANY of the others.  My own considered opinion is that 'context' is a kind of dustbin category, used by people to refer to that part of the problem of specifying meaning they don't yet understand properly.

  If you can come up with something like a definition of what you mean, I would be interested in discussing how to formalize it. Your first sense, which has to do with temporal distinctions, has already been thoroughly analyzed and formally specified.


    Dick McCullough
    knowledge := man do identify od existent done
    knowledge haspart proposition list

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Received on Tuesday, 3 December 2002 16:03:19 UTC

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