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

From: pat hayes <phayes@ai.uwf.edu>
Date: Tue, 3 Dec 2002 16:22:47 -0600
Message-Id: <p05111b22ba12dcc00dfe@[10.0.100.247]>
To: "Richard H. McCullough" <rhm@cdepot.net>
Cc: "Brian McBride" <bwm@hplb.hpl.hp.com>, <www-rdf-comments@w3.org>
>I have consistently used the same definition of context 
>(<http://rhm.cdepot.net/doc/KEtutorial.txt>http://rhm.cdepot.net/doc/KEtutorial.txt)
>     space = where action occurs
>+  time = when action occurs
>+  view = proposition list which captures prior knowledge

Well, OK, but that is a very odd collection of disparate kinds of 
thing,  seems to me, which have very little in common (and very 
little in common with the other uses of that word in other, er, 
contexts). What is the connection between actions and propositions, 
for example? And in the first two cases, where are the spatiotemporal 
boundaries drawn? Take this email conversation that we are having and 
other people are maybe reading: what is the space where that action 
is occurring?

>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.

I recall. Things havn't gotten any better, you know.

But more seriously, we can't be expected to use *your* definition of 
context in a language intended for general Web use all over the 
planet. If we try to use a 'general' notion of context we will 
dissolve into smoke. And in any case, the purely functional 
requirements of distributed knowledge-processing architecture require 
that we reduce such contextuality as much as possible. Take your 
second example, where a sentence's truth depends on the 'context' of 
the document in which it occurs, and ask yourself what happens when 
parts of such documents are being distributed across optical fiber, 
processed, inferences drawn from them, conclusions archived and then 
re-transmitted arbitrarily long times later, and used in other 
contexts far from their original source. If meaning depends on 
contexts which can vanish in microseconds, as they will in the SW, 
then meaning becomes meaningless.

Pat

>============
>Dick McCullough
><http://rhm.cdepot.net/>knowledge := man do identify od existent done
>knowledge haspart proposition list
>
>----- Original Message -----
>From: <mailto:phayes@ai.uwf.edu>pat hayes
>To: <mailto:rhm@cdepot.net>Richard H. McCullough
>Cc: <mailto:bwm@hplb.hpl.hp.com>Brian McBride ; 
><mailto:www-rdf-comments@w3.org>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/>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/>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>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.
>
>Pat
>
>>============
>>Dick McCullough
>><http://rhm.cdepot.net/>knowledge := man do identify od existent done
>>knowledge haspart proposition list
>>
>
>
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Received on Tuesday, 3 December 2002 17:22:36 GMT

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