Dear John, (01)
> Dear Matthew,
> JFS>> The airlines have been storing such information in their
> >> databases for over 40 years without having a detailed ontology
> >> about the nature of places, times, things, and events.
> MW> Oh, of course, they have been holding the data for decades,
> > and fixing up/misusing data structures to do what they need.
> > But that is not the same as saying they have been using a 4-D
> > data model to do it, or as you say something with any explicit
> > ontological foundation. And since the data is adequate it is
> > possible to map that to a 4-D model.
> I agree that they have not used any explicit ontology and that
> much of it is very ad hoc. Yet after sufficient debugging,
> they get the correct answers, and those answers are compatible
> with a knowledge base that uses either a 4D or a 3D ontology
> MW> But that is quite different from it *being* a 4D model just
> > because it holds the necessary data.
> I certainly agree. (02)
MW: We seem to have reached agreemenmt here, provided compatibility
is defined as a mapping being available.
> MW> The problem is knowing which data of this sort is actually
> > independent of the upper ontology (i.e. it morphs when moved
> > from one to the other).
> If you start with an upper ontology, it might not be clear
> what lower-level aspects are independent of the top. But
> any correct low-level description of any aspect of reality
> should be compatible with any correct upper-level ontology. (03)
MW: Again with compatible meaning that a mapping is available. (04)
> (But there may need to be some conventions for mapping one
> description to the other.) (05)
MW: Exactly. This can also be done, at least to some extent,
between upper ontologies too of course.
> MW> The problem here is the spaghetti problem of having to
> > deliver pairwise interfaces.
> That is indeed a problem. But it is not clear which problem
> is harder to solve: align the upper ontologies of all the
> systems involved, or check whether their local predictions are
> correct. (06)
MW: I'm not suggesting that one needs to align the ontologies
of all the systems, only of the interfaces. That is what
reduces the number of interfaces from up to n**2 to n. (07)
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