On Jul 12, 2012, at 4:04 PM, Chris Menzel wrote: (01)
> Right, on reflection I think the only issue here is that there are two very
>different notions of "model" in the general KR community (in which I include
>the ontology community), one coming out of mathematic logic and the other
>coming out of engineering. (02)
And the latter sense is much more widely understood than the former, by about
three or four orders of magnitude. Which is why I avoided using the word
entirely when writing the RDF semantics specs, and used the circumlocution
"satisfying interpretation" for the logical sense of "model". (03)
> I think Ed was talking about the latter and I responded by talking about the
>former — rather hastily, as I've in fact commented on this distinction before.
>(Indeed, sets of axioms are sometimes called models as well, so there are
>perhaps two distinct notions coming out of logic.) We can't (an arguably
>shouldn't try) to prevent people in different communities from using the word
>"model", but it would probably help to reduce confusion if those of us who are
>in, or who talk to, people in both worlds should made a habit of qualifying
>the word with, e.g., "engineering" (e.g., architectural designs), "logical"
>(sets of axioms), and "semantic" (mathematical structures that interpret
>formal languages). Or something. (04)
See above. We don't have to use the term at all. (05)
Pat (06)
>
> -chris
>
> On Thu, Jul 12, 2012 at 3:54 PM, Obrst, Leo J. <lobrst@xxxxxxxxx> wrote:
> I think what Ed is getting at is something that was shown to be very
>important during Ontology Summit 2012, which is the distinction between
>specification/design/model and eventual artifact. In systems engineering (and
>of course many other domains), one encounters these notions all the time. I
>think a general theory of artifact (perhaps under a general theory of
>description and realization) in an extensional ontology will typically be
>sufficient (though hard). However, that general theory of description and
>realization may veer into or at least have to consider intensional aspects.
>Matthew West and Henson Graves, among others, had an extensive discussion
>about these notions for systems engineering in the Ontology Summit.
>
>
> Thanks,
>
> Leo
>
>
> From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
>[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Chris Menzel
> Sent: Thursday, July 12, 2012 3:35 PM
> To: [ontolog-forum]
> Subject: Re: [ontolog-forum] The class of the planet Venus
>
>
> On Thu, Jul 12, 2012 at 11:03 AM, Ed Barkmeyer <edbark@xxxxxxxx> wrote:
>
> John F Sowa wrote:
> > 4. The distinction between intensions and extensions can be used
> > for individuals as well as for sets, relations, functions, and
> > classes. The basic point is that the extension is something
> > in the world (or a model of the world), and the intension is
> > a definition that is used to characterize and identify the
> > thing or things in the world (or some model of the world).
>
> ...
> I do wish John had avoided the insertion of the parenthetical
> expressions in the above, because they weaken, perhaps to the point of
> confusing, his thesis.
>
> The reason I object to John's parenthetical references to "models of the
> world" is that most "models" in this sense are intrinsically
> intensional. The artefacts in models are /constructed from/ the
> intensions, and two such artefacts may indeed be different even when the
> thing they are models of is the same. A model of a building is not a
> building. Two different models of the same building are different
> things, each conforming to a particular characterization of the
> building, whether the building itself exists or not, and in fact,
> whether or not the building in being actually possesses those
> characteristics. (This is a critical idea in Herbert Simon's famous
> work "The Sciences of the Artificial", and in some of Ted Goranson's
> work.) So it is in fact very difficult to argue that two
> conceptualizations of model elements are 'coextensive'. The model
> element is a manifestation of the conceptualization, not the extension
> of it. I would go so far as to say that a model element is a Frege
> Zeichen -- a sign/symbol for the intension (Sinn).
>
>
> I'm afraid that, for the first time I can recall, I have to disagree with Ed
>here. For there is absolutely no reason why the elements of a semantical model
>of a logical language (including most any KR language) cannot be exactly the
>entities we "intend". Indeed, such "intended" models are typically exactly
>what we wish to be talking about when we use the language in question: The
>natural, intended model of the language of arithmetic contains the natural
>numbers; the natural model of an ontology for a manufacturing system might
>well contain exactly the actual machines on the assembly line. Furthermore, I
>must say that I am not sure what Ed means when he says that models are
>"intrinsically intensional" or that they are "constructed from intensions". In
>the theory of models for logical languages, this is just not the case; the
>notion of an intrinsically intensional entity is simply not a part of the
>theory. Moreover, I am not sure we've got enough of a grip on the notion of an
>intensional entity beyond the idea that that distinct intensions can have the
>same extensions. This is represented in possible world semantics by defining
>extensions as functions from worlds to extensional entities of one sort or
>another. It is represented in the semantics of Common Logic simply by
>distinguishing between semantic objects and their extensions, but there is not
>much more to be said about the nature of intensions than that — formally, at
>any rate.
>
>
> So, while I think the distinction between intension and extension is
>certainly legitimate, I am skeptical of their introduction into the modeling
>domain in any sense beyond the well-understood (and ultimately extensional,
>from a purely formal perspective) representations found in possible world
>semantics or Common Logic.
>
>
> -chris
>
>
>
>
> _________________________________________________________________
> Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
> Config Subscr: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/
> Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
> Shared Files: http://ontolog.cim3.net/file/
> Community Wiki: http://ontolog.cim3.net/wiki/
> To join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J
>
>
>
> _________________________________________________________________
> Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
> Config Subscr: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/
> Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
> Shared Files: http://ontolog.cim3.net/file/
> Community Wiki: http://ontolog.cim3.net/wiki/
> To join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J (07)
------------------------------------------------------------
IHMC (850)434 8903 or (650)494 3973
40 South Alcaniz St. (850)202 4416 office
Pensacola (850)202 4440 fax
FL 32502 (850)291 0667 mobile
phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes (08)
_________________________________________________________________
Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
Config Subscr: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/
Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
Shared Files: http://ontolog.cim3.net/file/
Community Wiki: http://ontolog.cim3.net/wiki/
To join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J (09)
|