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Re: [ontolog-forum] Truth

To: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>, John Bottoms <john@xxxxxxxxxxxxxxxxxxxx>
From: "Obrst, Leo J." <lobrst@xxxxxxxxx>
Date: Mon, 6 Aug 2012 20:29:13 +0000
Message-id: <FDFBC56B2482EE48850DB651ADF7FEB01E772355@xxxxxxxxxxxxxxxxxx>
I largely agree with Pat, that many unanalyzed problems are swept under the 
"context" rug. But I think we can talk more specifically about "context" 
occasionally, perhaps along the way to analyzing some aspects of "context" so 
that some dirt remains exposed on the floor.    (01)

E.g., I am initially thinking about indexicals and demonstratives, which 
typically figure in some notions of "context". I don't know the full literature 
on these, but I do know some, like Kaplan (1989, "Demonstratives"), Lewis 
(various). [I know a lot of people have problems with Lewis's modal realism ... 
] Admittedly, these are "simple" compared to other notions of context, i.e., 
they index time, location, speaker, etc.    (02)

Also, concerning a more general notion of "context",  I recall some papers of 
Chris Menzel (1999) and others, who (perhaps) considered "contexts" in terms of 
the correspondence relation between a proposition and the world (or possible 
worlds or situations), and so as a kind of refinement of the accessibility 
relation between possible worlds, at a deeper level of granularity, say, as in 
Situation Semantics or Discourse Representation Theory. Semantic 
underspecification in computational semantics, e.g., does really focus on a 
specific kind of conversational/discourse context, a kind of conversational 
game, where the disambiguation occurs eventually but can be upturned at nearly 
every point.    (03)

So, in natural language semantics, context has meant more, e.g., Barwise and 
Perry's Situations and Attitudes (1983), Discourse Representation Theory (Kamp 
& Reyle, 1993), Kratzer's situation semantics article: 
http://plato.stanford.edu/entries/situations-semantics/.     (04)

Is context a thing apart from logic? No (at least, I don't think so), but David 
Lewis and others (John McCarthy, Robert Stalnaker, etc.) tried to tease out 
notions of context, so that they could be formalized. E.g., epistemic 
contextualism: http://plato.stanford.edu/entries/contextualism-epistemology/, 
which has close correlations to propositional attitudes (and their 
presuppositions) in natural language semantics. I also see this in so-called 
hybrid logics, in which propositions are true with respect to a state.     (05)

So maybe we shouldn't throw the baby out with the bathwater (or push it under 
the rug)?    (06)

Thanks,
Leo    (07)

-----Original Message-----
From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx 
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Pat Hayes
Sent: Wednesday, July 25, 2012 12:45 PM
To: [ontolog-forum] ; John Bottoms
Subject: Re: [ontolog-forum] Truth    (08)


On Jul 25, 2012, at 6:44 AM, John Bottoms wrote:    (09)

> On 7/25/2012 7:25 AM, John F Sowa wrote:
>> On 7/25/2012 12:45 AM, Pat Hayes wrote:
>> 
>>> JMcC's point was that there was no single "theory" of contexts; that
>>> contexts are not a natural kind, and a "context" is just anything
>>> that anyone cares to use in a context kind of a way, ie as something
>>> that influences truth values and denotations.
>>> 
> It almost sounds like there are two definitions of "context".     (010)

Two? TWO??? I attended several workshops and meetings on the theme of contexts 
and context reasoning. At one of them I took careful notes. Over three days of 
talks, no two speakers used the same sense of "context". They were all talking 
about different things, ranging in scope from a psychological state lasting a 
few miiliseconds to an entire human culture lasting millennia. When people say 
"context" they simply mean "all the stuff that I havn't got an explicit theory 
of".  I have in fact offered this as a definition of "context" at the 
Heidelberg ontology meeting (which John Sowa was also present at):     (011)

Context
The meaning of language is influenced by a very large number of factors. No 
theory of meaning is comprehensive enough to account for all of these; 
particular theories of meaning focus on some and analyze them in detail, and 
ignore others completely. For each such theory of meaning, the combined effect 
of the factors which the theory does not explicitly address is often called a 
"context".     (012)

> One is the perceived setting which may evoke observations based on the level 
>and type of perception. While the other is the brute-force real world set of 
>facts? Is this correct?  And if so, should we have different terms by the type 
>of context we refer to?    (013)

The brute force real world (or part of it) is the context, not facts about that 
real world. Contexts are objects.  For more on this, see my paper on 'contexts 
in context' at the AAAI context symposium, visible at   http://bit.ly/N2yGYa .  
But they key point is that there are not two or even twenty-two 'kinds' of 
context, but that being a context is more like a status or role than an 
ontological type. ANYTHING can be a 'context' in the right, um, context.     (014)

> JB: My fear is that by not defining a context type we will disparage its use. 
>That would be awkward.    (015)

What do you see the "use" of contexts as being? Personally, I think we would 
make great progress (indeed, we ARE making great progress) by eliminating all 
talk of "contexts" entirely, and doing our utmost best to forget about the term 
as being pre-scientific and confusing. If you want to think about how time 
influences meaning, think about temporal logics. If you want to think about how 
beliefs influence meaing, think about epistemic logics. If you want to think 
about fiction, study literary theory. But don't think that by calling all these 
(and so many other things) all "contexts" that you have thereby achieved any 
kind of insight or clarity. All you have done is get time and belief and 
fiction muddled, ie created confusion.    (016)

Pat    (017)


>> I agree with that idea.
>> 
>> 
>>> my (often repeated) objection that time, for example, and belief,
>>> for example, were very different kinds of thing and influenced
>>> truth in very different kinds of ways...
>>> 
>> I also agree with that.
>> 
>> 
>>> his response was always that the point of a context logic was not
>>> to capture the essence or nature of contexts, but rather to be simply
>>> a general framework for stating inferences which might be influenced
>>> by *any* kind of context.
>>> 
>> And I have no objection to that idea.
>> 
>> JFS
>> 
>>>> "(that p)" is a kind of quasi-quotation that allows
>>>> variables in p to be bound to quantifiers outside of p.
>>>> 
>> PH
>> 
>>> Hmm, I don't think it is correct to think of it as quasi-quotation.
>>> Rather than quoting the sentence, it treats it as defining a
>>> zero-ary predicate, and creates a term denoting that entity.
>>> 
>> The backquote in LISP can be applied to any expression.  The IKL
>> 'that' operator can be implemented in LISP by applying backquote
>> to sentences in some version of logic.
>> 
>> That is an explanation that is meaningless to anybody who does
>> not know LISP.  But LISP aficionados like that way of talking.
>> 
>> In any case, I agree that your definition is the proper way
>> to define 'that' in purely CL or IKL terms.
>> 
>> John
>>  
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