On 2/10/07, Charles D Turnitsa <CTurnits@xxxxxxx> wrote:
> Continuing our earlier discussion on the dimensions of ontology, do you
> think there is a value in measuring "closed world" vs. "open world"
> ontologies? (01)
I think there is Chuck
Thanks for picking up on that idea, it may be an important one. (02)
Closed ontology support a closed system - they have a value and a
purpose but we should be aware of their limitations (as said below) (03)
open ontology is better suited to open, evolutionary systems (like the
world wide web)
I leave you to extend the definition there (04)
>
> If so, do you see commonality, in this dimension, between what Adrian is
> trying to express, and the idea of having an intensional vs. an extensional
> definition of the domain?
>
well, I suspect that 'open' may also be intensional?
so that would need further thinking perhaps (05)
Paola Di Maio
>
> > > Actually, if there is to be a new Wikipedia or other encyclopedia entry
> on
> > > logic for ontologies, it should summarize the ongoing debate between
> the
> > > "closed" and "open" world negationist camps.
> >
> > I would welcome that, but I wonder how many rounds it will take to get a
> > version that is acceptable to most of the parties involved.
> >
> > It is my impression that there are at least 3 importantly different
> models of
> > the "closed world", and they probably relate to what kind of inferences
> the
> > "camp" wants to make. Further, there are several problems that
> > arise when the
> > closed worlders need to mix "closed" concepts and "open" concepts.
> >
> > One can, for certain "instantaneous" inferences, assume that the universe
> is
> > finite and consists only of things recorded in the current information
> base.
> > But to account for the evolution of that information base over time, one
> > obviously cannot make that assumption. And one has to step very
> carefully
> > through the swamp that is created when these notions get mixed. That is
> why,
> > Michael Kifer, for example, says that all rules languages are programming
>
> > languages. They model a carefully chosen inferential procedure.
> >
> > As to Adrian's examples:
> >
> > > Almost all uses of databases
> > > in our everyday life rely on things like "if it's not in the catalog we
> > > don't stock it",
> >
> > This is probably a business rule. It is true because, like Jean-Luc
> Picard,
> > we "make it so".
> >
> > > "if no flight number to Podunk is in the database, then
> > > there is no flight to Podunk"
> >
> > that we can do anything about.
> >
> > The speaker doesn't actually care whether there is a flight to Podunk; he
> is
> > focussing only on knowledge that affects HIS behavior. But knowledge
> that
> > does not affect his behavior might very well affect the behavior of
> > some other
> > person who has access to the same information.
> >
> > > so we should not ignore closed world
> > > usage of
> > > databases just because the clasical logicians never wrote about it.
> >
> > I'm not a crazy evangelist for monotonicity, either. I only point out
> that
> > closed world systems are designed for a particular purpose, and in
> general,
> > you cannot use them safely for inferencing for any other purpose.
> >
> > -Ed (06)
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