Re: SUO: RE: RE: A proposed SUO content outline
"West, Matthew MR SSI-GREA-UK" <Matthew.R.West@is.shell.com>, to Ian Niles:
> > On the basis of Pat Hayes' and Chris Partridge's comments, the classes
> > 'Occurrent' and 'Continuant' were replaced with the classes
> > 'OccurrentType'
> > and 'ContinuantType', which are classes of classes of occurrents and
> > continuants, respectively. This change was motivated by the
> > fact that the
> > distinction between occurrent and continuant is more stable
> > with respect to
> > type descriptions than with respect to individual things
> > themselves. Note
> > that 'OccurrentType' and 'ContinuantType' are both immediate
> > subclasses of
> > 'Entity' in the merged ontology.
>
>MW: This does nothing to help. It only means that instances of those classes
>have no members in any part of the ontology I have presented an outline for,
>since the members of members of continuent type must be continuents.
I agree.
>MW: You may recall that I have said a couple of times that at least the 4D
>ontology I am working on should be mapped to and not combined with the
>workyou are doing. The reason is that in a 4D ontology there are no
>individuals that are continuents. That is because the basis for what an
>object is is different. On the other hand, from a 4D individual, you will
>always be able to infer an occurrent (it might even be the same object - I'm
>not sure)
I think it is more likely to be the lifetime of the object.
>and sometimes you will be able to infer a continuent, but this
>will definitely not be the same thing as the object from which the
>continuents existence is inferred.
<snip>
> >
> > (documentation Object "A Physical Continuant which retains
> > its identity over
>
>MW: Continuant does not compute in "my" ontology.
Matthew, I think you could get continuants into a 4-d ontology by
thinking of them as a certain class of temporal cross-sections of a
4-d history. Given a history, consider the set of all spacelike (ie
perpendicular to the time-axis) 'slices' of it: that set always
exists, and it is 1:1 with the history but not identical to it. For
histories of continuants, the things in this set will 'be' the
continuant at the various times in its lifetime (to speak for a
moment in continuant-talk) ; for other histories they won't, of
course, but they might still be worth allowing to exist. The
characteristically 'continuing' nature of continuants, to which those
wedded to that way of thinking attach so much importance, may be
phrased in terms of what Nicola calls identity criteria on the things
in these slice-sets. For example, from the history (lifetime) of a
person, this would construct the (single) person at each moment in
that person's life. Each of these would 'be' that (single) person at
a particular time, so if we were to (re)construct a temporal or modal
logic by thinking of times - temporally possible worlds - as slices
through the 4-d universe, then these things would be the (individual)
continuant in each temporally possible world.
This move would allow a 4-d ontology to accomodate
continuant/occurrent talk quite naturally, I believe, even though it
would not be a mapping that those who like that way of talking would
approve of.
> >
> > some interval of time. Although no physical entity is ever
> > permanent, an
> > object
> > can have stable properties over its lifespan. The type Object
> > corresponds
> > roughtly
> > to the class of ordinary physical objects.")
>
>MW: Anything that has anything to do with continuant might have a related
>object in a 4D ontology, but it would not be the same abject. Thus all the
>classes that you are talking about are different classes because they have
>continuants as members and not 4D object, so they have different
>memberships.
Indeed, these types would have to be taken apart more carefully in a
full 4-d ontology.
<snip>
>
> > > > >
> > > > > Temporal Boundary
> > > > >
> > > > > Contains axioms and relations that apply to all individuals
> > > > > that have a zero temporal extent.
> > > >
> > > > It sounds like "Temporal Boundary" corresponds to the class
> > > > of 'Abstract',
> > > > another direct subclass of 'Entity'. Some axioms regarding
> > > > 'Abstract' can
> > > > be found in the section "General Axioms" of the merged ontology.
> > >
> > > MW: No. These are things that exist in space time, so they cannot be
> > > classes. They just have a zero extent in the time dimension,
> > > they are at a
> > > point in time.
> >
> > OK, so the items in this category would be indivisible slices
> > of space-time
> > worms?
>
>MW: In the sense that anything that has zero thickness is indivisible.
Yes, but be careful: there might be indivisible things which do not
have zero thickness. For example there might be an nonzero atomic
time-duration ('planck time'?) . Many temporal databases use
date/time stamping which makes this assumption implicitly. I discuss
this issue in the 'time catalog'.
>On
>the other hand it is not indivisible spatially. Further the objects that
>they are slices of do not have to be contiguous either spatially or
>temporally.
Ah, then I withdraw my earlier suggestion that they be thought of as
spacelike boundaries: they must be collections of parts of spacelike
boundaries. Interestingly, I have found a need for a purely spatial
notion like this (a set of pieces of surface all in some relation to
one another): it is precisely the general notion of a shape; so one
could characterize your notion as the temporal equivalent of a 3-d
surface shape.
<snip>
> > > > Currently, we have 'Proposition' as a direct subclass of
> > > > 'Abstract' in the
> > > > merged ontology. However, as Pat Hayes has pointed out, it
> > > > is likely that
> > > > the composite notion of 'ContentBearingThing' will prove to
> > > > be more useful.
> > > > In any case, axioms about these notions have yet to be written.
> > >
> > > MW: I don't think proposition is the same as information
> > > pattern, unless you
> > > think your DNA is a proposition.
> >
> > I agree, and the interesting example of a DNA strand fits
> > into the current
> > structure of the merged ontology. 'ContentBearingThing' is a direct
> > subclass of 'Abstract' (not 'Proposition') and 'Object'. Hence, by
> > subclassing DNA somewhere under 'ContentBearingThing' we capture its
> > informational quality, without claiming that it states a proposition.
>
>MW: That's interesting. So a piece of paper with writing on it is abstract.
>Now I always thought you could pick a piece of paper up?
>
>MW: I think you have a problem. A piece of paper is either abstract or not.
Right. I hadnt noticed this before: but obviously one cannot simply
put ContentBearingThing both under Abstract *and* under Object, since
these categories are mutually exclusive.
Ian, I think you are wanting a semi-lattice, but you are trying to
make one out of a tree. That won't work. Let me repeat a query I made
a while ago: what are the basic inheritance rules of your overall
structure? It seemed to be a classification tree, but you are no
longer using it in a way consistent with its being a tree. So what is
it? If it is a semilattice then you need to say both what is under
what and *also* what is disjoint with what, and do so explicitly. But
I would urge that you consider the approach of formal concept
analysis http://php.indiana.edu/~upriss/fca/fca.html also well
described by John Sowa
http://www.bestweb.net/~sowa/misc/mathw.htm#Lattice which allows a
considerable degree of freedom to assign concepts, and will compute
the 'smallest' appropriate inheritance structure automatically.
Pat Hayes
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