RE: SUO: RE: A proposed SUO content outline
>Dear Pat and Ian,
>
>
> > > >
> > > > State
> > > >
> > > > Contains axioms and relations that apply to all individuals
> > > > that have a non-zero temporal extent.
> > >
> > >I don't see how "State" differs from "Individual". Since
> > all individuals
> > >exist in space/time, wouldn't they necessarily have a
> > non-zero temporal
> > >extent?
> >
> > No. Something can be temporally located but have a zero extent.
> > Timepoints are the obvious example, but more 'physical' examples
> > might be instantaneous events like lightning flashes, or beginning
> > and endings of longer events.
>
>MW: Actually lightning flashes would not count for us. The duration is
>certainly very short, but it is both finite and positive. Only the beginning
>and ending of states, and points in time qualify.
OK, you are being strict about dimensionality, which is good practice, I agree.
> >
> > The situation calculus is hopelessly limited for a general physical
> > ontology. A process ontology would be a more generally useful overall
> > framework.
>
>MW: This is what I think we call Activity.
>
> > There are a number of quite elaborate process ontologies
> > in the public domain, any of which would be better than the sitcalc.
> > At a minimum, we need notions of process and subprocesss;
<snip>, summed up as:
>MW: We can do all that.
Yes, I do not doubt it. Only a 4-d ontology would be sufficiently
expressive, I am sure.
> >
><snip>
> > >
> > > >
> > > > Status
> > > >
> > > > Contains axioms and relations that apply to all classes that
> > > > are characteristics or qualities that is described by discrete,
> > > > unordered values.
> > >
> > >I agree that this is an important category, and it is also a
> > gap in the
> > >current version of the merged ontology.
> >
> > I have no clear idea what you guys are agreeing on. Can anyone give a
> > couple of examples of what this means?
>
>MW: examples would be painted, open, approved.
Why would these not simply be properties?
> >
> > >
> > > >
> > > > Organisational Level
> > > >
> > > > Contains axioms and relations that apply to all classes that
> > > > define the level of structure, e.g. atom, molecule, cell,
> > > > organism.
> > >
> > >I'm not sure exactly what you mean here. Do you envision
> > having a predicate
> > >that would relate a class with a quantitative or qualitative
> > attribute
> > >specifying the level of granularity of the class? This
> > might be a good
> > >idea, and there is nothing like this in the current version
> > of the ontology.
> > >Note that the folks at the Ontology Group at ITBM-CNR have
> > developed an
> > >ontology called "Granularity" to cover just this sort of
> > representational
> > >need.
> >
> > Everyone agrees that there is a need for this, but not many people
> > know how to do it!
>
>MW: I think we have identified some general principles and some useful
>organisational levels(following some of Nicola's work) but I agree there is
>a lot of work to do here.
The key issue is that granularity and inference are fundamentally at
odds with each other, since if you allow sub-granularity differences
to be 'invisible', and you allow inferences to be stored and re-used
(which is valid in almost any semantics), then you can generate
'heap' paradoxes (take one grain of sand from a big heap leaves it
big; taking n away for some n>0 doesn't.) All the proposals I know of
run into this apparently trivial point somewhere or other.
> >
><snip>
> >
> > >
> > > >
> > > > Set
> > > >
> > > > Contains axioms and relations that apply to all mathematically
> > > > defined sets.
> >
> > The idea of a 'mathematically defined' set is a bad idea. There is no
> > clear category of a mathematical definition (as opposed to a
> > nonmathematical one), and in any case what is in a set isn't
> > determined by the form of the definition.
>
>MW: No but what things are sets is. I only mean here that to be a set you
>must be iteratively constructed,
Oh no no. Consider the set of all noncomputable numbers, for example.
>and you can't for example have yourself as
>a member. As far as I can make out this is common ground for what a set is
>consdered to be. But I'm prepared to hear that the contrary is true.
Actually, there are "non-well-founded" set theories where a set can
be a member of itself, but they are new and not considered infra-dig
in many mathematical circles.
Pat Hayes
---------------------------------------------------------------------
IHMC (850)434 8903 home
40 South Alcaniz St. (850)202 4416 office
Pensacola, FL 32501 (850)202 4440 fax
phayes@ai.uwf.edu
http://www.coginst.uwf.edu/~phayes