RE: SUO: RE: RE: Basics of Process and Event, 3D and 4D
Dear Pierre,
I agree that other identity criteria could be taken, and
that the one we have taken is strong. I can only say that
I have had no cause to regret this. If you take something
weaker, you need some other explanation of when a spatio-
temporal extent is two objects.
This is a problem for 3D ontologies anyway, and one of the
things I like about this form of 4 dimensionalism is that
it gives an absolute and consistent answer, which also gives
a good explanation of many of the issues you find with
coincidence with 3D ontologies.
Matthew West
Principal Consultant
Shell Information Technology International Limited
Shell Centre, London SE1 7NA, United Kingdom
Tel: +44 20 7934 4490 Other Tel: +44 7796 336538
Email: matthew.west@shell.com
Internet: http://www.shell.com
> -----Original Message-----
> From: Pierre Grenon [mailto:pierre.grenon@ifomis.uni-leipzig.de]
> Sent: 20 June 2003 14:22
> To: West, Matthew R SITI-ITPSIE
> Cc: Standard-Upper-Ontology (E-mail); Fowler, Julian
> Subject: Re: SUO: RE: RE: Basics of Process and Event, 3D and 4D
>
>
> Dear Matthew,
>
> I had to abstain from wandering on SUO lately (but for Jon's
> tutorials which I
> always make a point to followreligiously), I'm pleased to see
> that there's good
> stuff going on now.
>
> Comments on your (3) below.
>
> Best
> Pierre
>
> > > >
> > > 4 dimensionalism as I learnt if from Chris Partridge, as I
> > > had confirmed by Pat Hayes and as stated in Ted Sider is
> > > founded on the following propositions.
> > >
> > > 1. Existence is a manifold of 4 dimensions, 3 space and time.
> > > I.e. when I refer to things in the past they exist, and
> > > when talking about the world I stand outside time.
> > >
> > > 2. Individuals extend in time as well as space and have
> > > temporal parts as well as spatial parts.
> > >
> > > 3. When 2 individuals have the same spatio-temporal extent
> > > they are the same thing.
>
> There is a difference between having the same spatiotemporal
> extent and having
> the same (spatio)temporal parts. The former is about location
> in spacetime, the
> latter about mereology. (Unless I missed a terminological
> consensus about
> extent in your discussion.) In a substantivalist treatment of
> spacetime, having
> the same spatiotemporal extent is called colocation or
> coincidence. If you
> treat extents as parts of some kind of the entities existing
> in spacetime, then
> having the same spatiotemporal extent means overlap. (Even in
> this latter case,
> it is not obvious that the entities only have parts which are
> extents of this
> sort, so even here colocation doesn't collapse trivially to equality.)
>
> It seems odd to me to require (3) as a principle for 4-D . I
> see that this
> could be endorsed by some 4d theories and rejected by others.
> Inter alia, it
> depends on how you regard spacetime itself.
>
> > > JPF> I know what the intent here, but it doesn't come across
> > > in this wording. How about "when individuals are identified
> > > or described as being distinct but have the same
> > > spatio-temporal extent, they are the same individual".
>
> IMHU, this means the same thing as the previous statement or there is
> somethimng fishy about 'identification' and 'description'.
>
> > > Otherwise there is a mapping problem for individual <-> thing.
> >
> > MW: I think the "formal" definition goes something like:
> >
> > For some x and some y, for all z iff z is a part of x and z is
> > a part of y then x=y.
> >
> > i.e. they are the same if they share all their parts.
>
> There is an axiom of mereology which claims that (it's
> usually laid down with
> prper part). So you seem to take spatiotemporal extents as
> parts of entities?
> Again, see above, even if this is the case, why sharing
> extents means sharing
> all parts?
>
> The principle 3 is:
>
> For all x for all y (if x and y are spatiotemporally
> colocated then x = y)
>
> (Again I think this is rather strong for a general version of
> 4D. The converse
> is trivial however.)
>
> > > It is still possible to go in different directions from there,
> > > but that foundation of what individuals are is shared.
>
> Don't think so. 3 is optional.
>
> [...]
> > > thing. Item 3 is the one most at risk.
>
> Indeed.
> --
> Pierre Grenon
> IFOMIS Uni Leipzig
> Haertelstr. 16-18
> 04107 Leipzig
> http://people.ifomis.uni-leipzig.de/pierre.grenon/
> pgrenon@ifomis.uni-leipzig.de
> phone: 49(0)351971672
> fax: 49(0)3519716179
>