Dear Pat, (01)
> >>> That depends on how you define individual (of course).
> >>
> >> I had thought that there was a starting point here in which the
> force
> >> of being an individual was that one does not have instances or
> >> exemplars (or 'members'), so I have been using this idea for making
> >> intuitive judgements of plausibility, rather than any formal
> >> definition. This has nothing at all to do with being in space and
> time.
> >
> > MW: Someone (not me) proposed that, and I have been trying to say
> that
> > whilst what I mean by a individual does not have members, that does
> > not mean that everything that does not have members is an individual
> > (e.g. the null
> > set) and then you started shouting.
>
> :-) But Matthew, there is something peculiar going on here. There is a
> discussion going on using a word ("individual') which is really about
> an idea: a somewhat murky idea, with a long history, but still, an
> idea; the distinction between things that in some sense can have
> instances and those that are too 'particular' to have them, again in
> some murky sense. Then you arrive and tell us that you use this word in
> a wholly different way to refer to something completely different. (02)
MW: Well I was really trying to do something simpler than that, and explain
that something that is an individual (OWL sense) might also be a class, but
things got side tracked. (03)
> Well, OK, you can be Humpty if you like, but what relevance does this
> remark have to the discussion at hand? If someone were to tell us that
> what they mean by "individual" is an umbrella made in Poland, then all
> that follows is that they are not having the same discussion that the
> rest of us are having.
>
> But put that aside, and I'll respond to the rest of your message as it
> is written.
>
> > MW: But let's back up a bit, because Chris mentioned individual as a
> > foundational object, and for what I mean, what I mean by individual
> is
> > not really that either. So if I look at what I see (in my scheme of
> > things, your mileage may vary) as foundational objects, my list would
> be:
> > - set/class - things for which the membership/instance of
> relationship
> > is
> > valid)
> > - spatio-temporal extent - things for which mereotopological
> > relationships are valid.
>
> Are there things for which both membership and meretopology are valid? (04)
MW: Not as far as I know. If you have some examples you think might be both
we could consider them. (05)
> Do the set/classes and spatiotemporals overlap, or are they disjoint? (06)
MW: Well I don't know any spatio-temporal extents that have members. Again,
if you can provide examples that you think do, I would be interested. I know
some people think of classes as having the spatio-temporal extent of their
members. I think that confuses sets with mereological sums. One of the
things you need to get consistency in a community of ontologists is to do
things the same way when there are alternatives. It's not about right or
wrong, just about consistency, where there are choices you need to make one,
even if it does not particularly matter which way you go. (07)
> (Why?) (08)
MW: Why not?
>
> > A spatio-temporal extent is a spatio-temporal part of (classical
> > mereology) some possible world.
>
> Hmm. I would rather say that a possible world is a maximal extent (an
> upper limit of the partof relation) and have the Kripkean
> alternativeness apply to parts. You get a lot more expressivity that
> way. (09)
MW: That sounds good. What is Kripkean alternativeness?
>
> > - relationship - what one thing has to do with another (not to be
> > confused with relations that are mathematical structures often used
> to
> > represent relationships - or more properly classes of relationship).
>
> I dont follow the relationship/relation distinction here, but let it
> pass.
>
> > - number - things for which mathematical operators are valid.
>
> Again, must it be disjoint from the others? Why? (010)
MW: Did I say they were disjoint? They seem to be to me, but if they turn
out not to be, that's just how it is. Again examples that suggest they
overlap would be useful.
>
> >
> > You could make an abstract/concrete divide between spatio-temporal
> > extents and the rest (and I have in models) but I would agree that is
> > not foundational and can be abandoned without losing anything.
> >
> > For me an individual is a kind of spatio-temporal extent.
> Specifically
> > it is the whole of the life (not to be confused with lifecycle) of
> > some object of interest in some possible world, e.g. me, the computer
> > I am typing on, the singing of a song, Moby Dick.
>
> I have problems with Moby Dick; in what sense can you say that a
> literary work has a *spatial* extent? (011)
MW: Ah, I had Moby Dick as the Whale, not the book, though it makes little
difference. The way I see the book title Moby Dick is that there is a
possible world in which the story of Moby Dick is the case, and the author
writes this down in his manuscript (a spatio-temporal extent) and creates a
representation of that possible world. There are then lots of other copies
of the book, and the book title works for me as the set of those, with
subsets for the different editions with different front matter, page layout
etc. I won't say there aren't other choices you could make, but this is
simple and seems to capture the situation. After that it is a matter of
consistency again, you don't want more than one way of doing something.
>
> > This contrasts with a state of individual which is a temporal part
> > (the whole spatially, but a part temporally) of some individual
> (again
> > classical mereology, so an individual is a subtype of state of
> > individual). So me today, a singing of the first verse of a song, etc
> > are states of individual.
>
> Yes, I do understand the 4-d picture; I used it in the old 'ontology of
> liquids' paper. But there seem to be a host of entities that don't fit
> into this scheme. (012)
MW: I'm always interested in things that don't fit. Whatever can break your
scheme means you can improve it. (013)
> Literary works,
MW: See above.
> ideas,
MW: Could you give some example? Normally I would think of an idea as a way
things could be, so it is possible worlds approach, but there might be other
sorts of idea. (014)
> colors, (015)
MW: Colours are tricky, I agree. It seems to me there are two treatments
that are actually different things. Physical objects are coloured because of
the light they reflect/absorb, but light itself has a wavelength that gives
it its colour. I'm reasonably happy that you can have a set of colour
classes (think pantone colours) that objects (or their parts) can be
classified by, and on the other hand light waves can be classified by their
wavelength. But I would accept that the former is pragmatic. (016)
> measuring scales,
MW: I presume you mean things like the Celsius Scale here. I actually think
we did a pretty good job of this in ISO 15926. A scale is a mapping from a
physical quantity (e.g. a particular degree of hotness) and a real number
(within a range). (017)
> physical properties such as length or hardness,
MW: This sounds like you do not mean a particular length or a particular
harness, but the set of all lengths or all hardnesses. Well we treat a
particular hardness as a set (of spatiotemporal extents that exhibit that
hardness). Then hardness is the set of those, so a class of class of
individual. It seems to work. (018)
MW: There are some bigger problems we found, length is easy enough, but if
you have a ship you have a plethora of different lengths, Length overall,
Waterline Length, Beam, draft, air draft,... (019)
MW: As far as I can see, physical quantities are conventional, and you can
always peel away layers. Temperature is an interesting example. It
disappears as you reduce the size of the object you are looking at down to
single molecules, because it is really a measure of the way the molecules
are moving around. (020)
> shapes,
MW: Not sure if it is what you mean, but the SC4 community has done a pretty
good job on shape representation. (021)
> appearances (022)
MW: Not sure what you mean here. Could you give some examples. (023)
> (what do we see when we see a face?),
MW: Features? Not sure what you mean. (024)
> contracts,
MW: Chris P has done some useful stuff on this. Quite important for an
organization like Shell. (025)
> sounds, ...
MW: never had to look at that... (026)
> Even a body of water gives one trouble, as I discussed long ago (is it the
> same lake when the water changes? Yes and no.) (027)
MW: We have the same problem with a continuous processes in the oil
industry. Essentially it's the same problem as a person in a position, with
each being distinct spatio-temporal extents.
>
> > I'm not sure how one can define an individual in this sense at a
> > logical level, in particular, what makes something an individual
> > rather than just the background mish-mash. (If you have some
> > suggestions I would appreciate them). But these are undoubtedly
> > important things, and we seem to know them when we see them.
>
> Do we? I find it very hard to make reliable judgements about the
> difference between your individual (a 'complete' history) and your
> state (a temporal part). Seems to me that we are very flexible about
> this. When a dancer finishes the dance, something certainly seems to
> have ceased to exist. Am I the same person I was yesterday? And so on.
> But more to the point, why do you need to make this distinction in the
> 4D ontology? I didnt find any need for it in the (admittedly limited)
> uses I made of it. All that was necessary was the notion of a history:
> a continguous 4-d chunk of space/time which had some interesting
> properties, which covers your individuals and their states under one
> heading.
MW: Well that is the way we treated it in ISO 15926, except we called it
possible_individual. It seemed to me that people using ISO 15926 were
thinking in terms of whole life individuals, and forgetting the states. So
having state of individual and individual, is really just adding detail to
help people use the model correctly. I've done it that way in my book. The
disadvantage is that it is more verbose, but again, it is really about
getting a community to use the ontology consistently. (028)
>
> Which illustrates what I believe to be an important methodological
> point. Rather than debate such distinctions in the abstract, the way to
> make progress is to note them, then deliberately ignore them and see
> how far one can get without making them at all; thereby *discovering*
> what distinctions are needed in order to state the axioms one wishes to
> write. (029)
MW: Broadly I agree. My caveats are around the practicalities of getting a
team to do the same thing in the same way. In developing ISO 15926 we took
an experimental approach, so we would try a particular structure, and then
try to break it. If it stood the test of practicality it stayed, if not we
thought again. We threw a lot away, including 3D (though that was mainly
because it gave so many arbitrary ways of modelling various things, whereas
4D was more rigorous). (030)
> If you discover how to use your original distinctions, fine; but
> you may discover other distinctions which are more suited to what you
> wish to say, and that your original distinctions were based on flawed,
> or simplified, intuitions. What I discovered in the liquids work, for
> example, was that the shape of a history comprising liquid was a
> fundamental importance in writing axioms, and that the notion of a flow
> through a piece of surface was critical, so I needed a notion of
> direction. Both are kind of obvious once pointed out, but I did not
> notice them up front, and I doubt if one would find them in Aristotle. (031)
MW: yes, we found space-time diagrams, and starting analysis from
individuals (before classes) to be critical to reducing the time it took us
to get to a good outcome. (032)
> (On the other hand, distinctions between kinds of fluid, which I might
> well have gotten sidetracked into cataloguing, were of no importance at
> all.) (033)
Regards (034)
Matthew West
Information Junction
Tel: +44 1489 880185
Mobile: +44 750 3385279
Skype: dr.matthew.west
matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
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