RE: SUO: RE: RE: A proposed SUO content outline
>Dear Pat,
>
><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.
>
>MW: I'm not sure I followed that. Do I understand that a continuant would be
>the slice of the 4D object at the time of interest?
Not exactly. It would be a *set* of slices, or if you prefer, a
property of such slices (ie the property of being in that particular
set). The point being that from the endurantist perspective, each
slice IS the thing in question (the continuant) *at a time*, since
continuants may endure through time - retaining their identity as
they go, as it were - and also they may have different properties at
the different times. So these various slices - which are distinct
things in a 4-d view - are one and the same 'thing' from the other
viewpoint. But that continuant-thing is *not* the 4-d 'worm' (I hate
that terminology, and will use my old terminology of 'history' from
now on), since unlike a history, a continuant is thought to be wholly
present at each moment during its lifetime. This actually does not
make sense in the 4-d ontology, strictly speaking; but one can come
very close to it by the trick I outlined above, in which the set
corresponding to the continuant is something like all the ways that
the continuant has been, as it has changed during its history. In 4-d
these are many things, but to an endurantist they are more like a
biography of a single thing. To endurantists, the notion of a 4-d
history of a continuant is meaningless (it would have to be an
occurrent; they would call it the continuant's lifetime); but the set
of slices is meaningful; it is the set of all the states the
continuant has been in. Endurantists can believe in abstract
flicker-books, even for things that have no temporal parts.
>So effectively the
result of a function on a 4D object?
Yes, but not the function you had in mind, I suspect. If slice(h,t)
is the t-slice of the history h, it would be the set {slice(h,t) : t
in when(h)}
> >
> > 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.
>
>MW: Well I think there is a point worth discussing here. In principle,
>anything that I can map to from a 4D ontology, I can incorporate into a 4D
>ontology, and you have just described how that might be done. My question is
>whether this the best way to structure things. You rapidly end up with
>something that is monolithic and confusing (at least).
I would claim that this flicker-book set is not unintuitive. By being
a set it is removed to an abstract realm, lifting it above the fray
between enduring and perduring; the things in the set are meaningful
to both endurantists and 4-d perdurantists, and both can agree that
they are totally ordered by time. The only thing they will disagree
about is how to individuate the things you get by squashing this set
back into one thing in space and time: endurantists will insist on
there being a continuant moving through time, while perdurantists
will insist on seeing a history extended in time. The former will
make distinctions which are rendered invisible by the latter's 4-d
extensionality principle. But they can agree to disagee about that,
without coming to blows over the set itself.
>MW: In practice I suspect that most people will want to work with one world
>view at a time (we all change world view as needs require). I therefore
>think that from a structuring point of view is is better to keep the world
>views as separate ontologies, at least along major fault lines like 4D/3D.
>The kind of relationship you describe above is precisely the mapping that
>would then be needed between them. However, let me be clear, this is a
>practical and not a theoretical point. Theoretically there is no difference.
No, I think there are genuine differences. I'm on your side, but one
has to admit that the 4-d ontology is not the most general possible:
it does insist on identifying things that other people want to keep
separate.
Pat Hayes
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