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Re: [ontolog-forum] Truth

To: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "doug foxvog" <doug@xxxxxxxxxx>
Date: Mon, 23 Jul 2012 17:24:03 -0400
Message-id: <5e7eb29df1c65bd52e45a0dd16ea899b.squirrel@xxxxxxxxxxxxxxxxx>
On Sat, July 14, 2012 02:03, Pat Hayes wrote:
> (Sorry Ive been off-email for a while.)    (01)

So have i.    (02)

> On Jul 11, 2012, at 3:16 PM, John F Sowa wrote:
>> On 7/11/2012 3:13 PM, Pat Hayes wrote:
>>> They are not context *logics*. There is no provision in CL
>>> for the referent of any name to vary with contexts.    (03)

>> What?!?!?!?    (04)

>> Where did you get requirement?    (05)

> Not sure I understand your question here. What I said is simply true of CL
> and IKL, as is obvious from their semantic rules.    (06)

Are you merely claiming that there is no inter-context reasoning in CL and
IKL, since there is no standard method of defining contexts?    (07)

That would mean that if someone wished to incorporate information from
isolated knowledge bases, they would automatically be merged.  For
example, if Allstate merged a knowledge base of its customers in
Texas in 1997 with one of new customers in Maryland, in 2012, its algorithms
upon finding a statement from the 1997 kb that a driver was 18 years old,
would charge the customer returning to the company in 2012 the rate for
teenage drivers, since the context of the driver's age was lost.  And it
would generate an error on an assertion  that the driver had been accident-
free for 23 years.  I would hope not .    (08)

>> For example, many logicians recommend that proper names in
>> natural languages be mapped to monadic relations in logic
>> rather than individual constants.    (09)

>> The name Aristotle, for example, would be true of the ancient
>> philosopher, and it would also be true of the second husband
>> of Jackie Bouvier.    (010)

>> If you want a theory in which names can vary with contexts,
>> then you can map each name in any NL to a dyadic relation
>> instead of a monadic relation.  The relation Aristotle(X,c),
>> for example, would be true iff the individual X had the
>> word 'Aristotle' as name in context c.    (011)

> Not quite. You have to associate the name (not the individual) with the
> context.    (012)

I thought you didn't accept contexts.    (013)

> In IKL you can treat a character string as a function, which
> handles this very nicely. We did this for the IKRIS project mappings, you
> may recall. There is an extended example involving Lacrosse in
> http://www.slideshare.net/PatHayes/ikl-survey (slides 21- 23) showing how
> elegantly it works. [For readers who think that the axioms shown there
> seem complicated, I invite you to try to formalize this example using any
> other notation of your choice.]    (014)

> But notice, none of this changes what names themselves refer to.
> ('Aristotle' c) refers to whatever the strong "Aristotle" refers to in
> context c, but that does not change what the actual name Aristotle refers
> to. IKL is a referentially transparent language throughout.    (015)

Are you distinguishing "Aristotle" and "the actual name Aristotle"?    (016)

Is one refering to a string, and the other to a constant in the KB?    (017)

>>> One could of course do whatever one chooses, but if the context
>>> is supposed to modify or help determine what URIs refer to, then
>>> treating a graph as such a context is explicitly prohibited by
>>> the RDF specification documents. So this would not be legal,
>>> conformant, RDF.    (018)

>> The conventions of RDF, OWL, and URIs are totally independent
>> of this discussion.    (019)

> The comment you cited here was made in response to a claim by Doug
> Foxvog, that an RDF graph could be considered to be a context,
> which is why I referred to RDF.    (020)

The RDF comment meant that within the graph a substatement is true,
but it is not necessarily true without the surrounding statements.  For
example, it may be true that (IF A THEN B), but that does not mean
that A is necessarily true, even if it is stated as an RDF triple.    (021)

>>  Any theory of contexts proposed by any
>> philosopher or linguist could be mapped to IKL in one way or
>> another.    (022)

> Maybe. IKL seems to be one of the most expressive first-order languages I
> have ever seen, but I wouldn't make such a large claim about it without
> some evidence.    (023)

Consider Cyc's microtheories.  They are the sorts of contexts which i
was referring to.  The assertions inside can be mapped to B
    (AND B1 B2 B3 ...)
while the defining assertions of the context can be mapped to A:
    (AND A1 A2 A3 ...)
[Converting this to masses of triples is an exercise for the reader.] 8)#    (024)

>> But the notations of RDF and OWL are far less expressive.  I couldn't
>> imagine anyone using them to reason about context logic.    (025)

> I could :-) .    (026)

You've got a good imagination.  8)#    (027)

> In fact I have explicitly suggested modifying RDF as a
> context logic to the RDF WG, but I don't hold out a great deal of hope
> that they will be willing to go along with the idea.    (028)

Why not a unary Turing Machine?   8)#    (029)

-- doug    (030)

> Pat    (031)

>>  Perhaps
>> one might represent the final conclusion of some deduction in RDF,
>> but that doesn't impose any requirements on RDF.    (032)

>> John    (033)

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