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Re: Conceptual Graphs, N3, RDF, Semantic Web

From: Jon Awbrey <jawbrey@oakland.edu>
Date: Wed, 17 Jan 2001 23:23:05 -0500
Message-ID: <3A666FA9.99C3E92A@oakland.edu>
To: fmanola@mitre.org
CC: RDF Logic <www-rdf-logic@w3.org>
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Frank Manola wrote:
> 
> I believe the definition of "reification" intended in the
> context of RDF is along the lines of McCarthy's, found at
>
> http://www-formal.stanford.edu/jmc/generality/node6.html
>
> to wit:

Yes, that was one of the several different definitions, and other sorts
of glosses, to which many people took a shine in our discussions on the
SUO List.  As a pragmatist about language usage I cannot (consistently)
tell other people how they "ought" to use signs, since I may not know
much about their goals and intentions, but I can observe the results
of a variety of different kinds of conduct, customs, practices, and
standards that are taken up in the field, and I can point out the
most likely consequences, as I gather them to be, of this or that
particular "form of usage" (FOU) -- that is about all to which
this kind of a "pragmatic critique" (PC) can really amount.
And I could be wrong about what I see, or project from it.

> > REIFICATION
> >
> > Reasoning about knowledge, belief, or goals requires
> > extensions of the domain of objects reasoned about.

This is an extremely important observation, under any name!

Note:  I will insert single quotation marks in the text below
to mark the expressions that were italicized in the original:

> > For example, a program that does backward chaining on goals
> > used them directly as sentences, e.g. 'on(Block1,Block2)', i.e.
> > the symbol 'on' is used as a predicate constant of the language.
> > However, a program that wants to say directly that 'on(Block1,Block2)'
> > should be postponed until 'on(Block2,Block3)' has been achieved, needs
> > a sentence like 'precedes(on(Block2,Block3),on(Block1,Block2))', and
> > if this is to be a sentence of first-order logic, then the symbol 'on'
> > must be taken as a function symbol, and 'on(Block1,Block2)' regarded
> > as an object in the first order language.

Yes, we clearly do not want our ReDeFoBots going off 'half-cocked',
as they say, acting on every signal that has the form of a command,
even if it is expressed in a declarative fashion, or believing every
statement that has the form of a declaration, especially when all that
the communicator may expect of the communicatee is to 'take the advice'
to consider it, to speculate a little bit about it, or maybe even to
inquire intuit, that is, to interrogate or to question it.

> > This process of making objects out of sentences and other entities
> > is called reification.

And there we have a parting of the ways ...

If I follow this usage, it will cut me off from the -- up til now! --
historical continuity of the word "reification"'s venerable usage,
or at least confuse me and others about the heck I am talking about.
And why do that, when the term "quotation" already covers the act
that makes a sign (sentence, text, and so on) into an object, that
is to say, more carefully observed and duly noted, the reflective
act of re-considering an object that was formerly cast in the role
of a sign -- of an object, to an interpreter, or else to an end --
and re-collecting it now as the object that it always already was,
all along.  As for the residue about "other entities", well, that
"alternative plural essence" (APE) will have to be made a bit more
specific as to its genus, species, or type before I dare to name
the genus, species, or type of operation that would render them
all indiscriminately as objects unto our site.

> > It is necessary for expressive power but
> > again leads to complications in reasoning.

And that is certainly true of 'it', under any name!

> It is discussed in (McCarthy 1979).
> 
> Whether RDF's reification accurately captures
> this intent is, of course, another question.

And there I think that we agree about something more than mere words.
 
> --Frank

> Frank Manola                   The MITRE Corporation
> 202 Burlington Road, MS A345   Bedford, MA 01730-1420
> mailto:fmanola@mitre.org       voice: 781-271-8147      FAX: 781-271-8752

Many Regards,

Jon Awbrey

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Received on Wednesday, 17 January 2001 23:22:44 GMT

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