On Aug 8, 2009, at 8:02 AM, Chris Partridge wrote:
> ...
> The reason I asked is that I have worked with Matthew (and David
> Leal) on
> and off over the last decade on a general framework for UoMs -
> sometimes as
> part of Matthew's ISO 19526 exercise (Matthew and David have been
> working on
> the UoM issue far more consistently and for much longer). What we
> found is
> that the choice of 3D/4D and extensionalism had a big effect on how we
> crafted our ontology, including property instances. (01)
I find that interesting, and would like to have been a fly on the wall
during your discussions. Is there any written trace of them? (02)
> I think this is why
> Matthew made his comment. For a simple example, see my earlier
> response to
> Ingvar, who nicely provided us with an example. (03)
Can you repeat that example? I seem to have missed it. (04)
> I am not aware of any definitive proof that property instances, 3D/
> 4D and
> extensionalism are either independent or dependent. It does seem as
> though
> 4d + extensionalism (for which Matthew sometimes uses the shorthand
> '4d')
> does have implications for property instances. However, these things
> are so
> entangled that there is always wriggle room. I interpreted your and
> John's
> comment that you had some way of showing that they were independent
> simpliciter. So, to be clear I have no way of showing these are
> orthogonal
> or not and would be interested in any such proof as my experience is
> that
> these matters are entangled - so some such proof would be useful. (05)
I will try to sketch the argument, though I would hesitate to call it
a proof. It amounts to defining a syntactic transformation from one
ontological formalism style to another, and then observing that one of
these can reasonably be seen as a formalism of the 4D picture, and the
other of the 3D one. The basic point is that there are only two ways
to insert a time parameter into a 'static' description: it either gets
attached to a relation name as an argument, or to an individual name,
converting them to a term. One writes either (R a b t) or (R (a t)(b
t)). The first is naturally read as a continuant-style description,
using time-dependent fluents to talk of things whose identity is
considered to be timeless, the latter as a 4D one, in which assertions
are made timelessly about 'slices' of a 4D entity. (There are other
ways, but they all involve changing the logic in some way, eg by
adding temporal contexts or tenses.) Basically, and oversimplifying
things greatly, one can convert from 3D to 4D and back by 'moving' the
temporal parameter between these two positions. This is an observation
about the formal notation, of course, but the philosophy is basically
irrelevant until it gets cashed out in a formal expression of some
kind. Whatever your views are on property instances, in particular,
can (if they are relevant to the final ontology) be ultimately
expressed in one of these ways, and when it is so expressed, can be
almost mechanically transliterated into the other, and from there
'read back' as being about the other kind of temporal entities. I
realize that this hardly constitutes a philosophically valid form of
argumentation, but then of course we are not here doing philosophy,
but rather ontology engineering: right? (06)
>
> I am not sure how to interpret your comments - you say that "The
> differences
> between them, I have concluded, are really nothing more than a
> matter of
> notational choice." In these terms, the issue becomes whether the
> notation
> choice of 3d/4d, extensionalism/intensionalism and property
> instances are
> independent. I still see no answer.
>
>>> However, you have said that this is obvious, so I presume you have a
>>> way of
>>> showing it.
>>> If you (or John) can explain, I'd be interested.
>>>
>>>>
>>>>>
>>>>>>>
>>>>>>>> In other discussions, you have consistently argued for an
>>>>>>>> ontology
>>>>>>>> that is strictly extensional. That is also an assumption that
>> is
>>>>>>>> orthogonal to the 3-D vs. 4-D viewpoint.
>>>>>>>>
>>>>>>>
>>>>>>> Are you sure orthogonal is the right word here?
>>>>>>> As far as I can tell (and others say the same) the views are
>>>>>>> interestingly
>>>>>>> intertwined. So, for example, it is rather difficult to be an
>>>>>>> extensionalist
>>>>>>> and not be 4D. Orthogonal seems to imply that there is no kind
>>>>>>> of
>>>>>>> dependence
>>>>>>> between the two.
>>>>>>
>>>>>> Indeed; and there is not. Of course it is possible to be a 3-d
>>>>>> extensionalist. You believe in continuants, and you say that two
>>>>>> continuants which share the same 3-d extension at every point of
>>>>>> their
>>>>>> common life, are identical.
>>>>>
>>>>> Not quite the traditional definition of extensionalism. But
>>>>> illustrates my
>>>>> point that it is difficult - but not impossible.
>>>>
>>>> There is nothing difficult about this, surely. It is easy to be an
>>>> extensionalist and not be 4D, is the point. The relevant form of
>>>> extensionalism has to be stated in 3D terms, of course.
>>>
>>> The difficulty is that of sticking to the traditional way of framing
>>> extensional identity where a single extension is used.
>>
>> But that is applied in a strictly presentist framework, where the
>> universe is conceptualized in three dimensions at a moment in time.
>> Obviously this must be adapted when we consider temporally extended
>> universes.
>
> I do not understand your comment. As has been pointed out a number
> of times,
> 3d/4d is shorthand for positions on the reality of change. (07)
Um... that is not how I am understanding it. The *reality* of change
seems to me to be beyond rational dispute. I see the distinction as
being about how best to formally describe change. (08)
> I am not sure presentists see any problem in including change over
> time - in
> fact, I would think they would claim presentism is precisely the
> best way of
> dealing with it. I bet they would think it odd to temporally extent
> their
> strict framework.
>
>>
>>> You have proposed a
>>> non-standard framing where a number (a set?) of extensions are used
>>> - so
>>> this may be called set-extensionalism, where an object is identified
>>> with a
>>> set of extensions.
>>
>> I would prefer to say that it is applied at each moment of time, and
>> not speak of sets.
>
> But is applied a number of times, and to check identity you need the
> set of
> such applications. (09)
It is not necessary to introduce 'set talk' into the ontological
description, however. That raises a lot of red herrings. (010)
>>> If one wanted to be picky one could say you were using
>>> extensionalism but not providing an extensionalist criteria. In my
>>> view,
>>> this is a pseudo-extensional criteria.
>>
>> Not in mine. But in any case, regardless of its traditionalist merits
>> or demerits, it is not *difficult*.
>
> We are plainly not going to agree. (011)
Plainly :-) (012)
>>>>>
>>>>> To be a 4-d nonextensionalist is also
>>>>>> easy, I am one myself. I believe there is a clear distinction
>>>> between
>>>>>> a plastic molded object, such as the 5-cent buddha on my desk,
>>>>>> and
>>>>>> the
>>>>>> plastic from which it is composed, even though they share exactly
>>>> the
>>>>>> same 4-D extent (the plastic having itself formed by catalysis
>>>> during
>>>>>> the molding process).
>>>>>
>>>>> Ok, but do you have any criteria for identity or difference to
>>>>> back
>>>>> up your
>>>>> belief they are different.
>>>>
>>>> I do not need to provide any such criteria. All Im setting out to
>>>> do
>>>> here is to claim that the position is coherent, not wanting to
>>>> argue
>>>> for it or against it.
>>>
>>> I am in the same position - I would like to have a coherent view -
>>> then one
>>> can consider whether to argue for or against.
>>> However, I think your claim to being coherent (if you are using in
>> the
>>> Wordnet sense of 'marked by an orderly, logical, and aesthetically
>>> consistent relation of parts') is far too strong. The problem is
>>> that you
>>> give no basis for deciding how many things share the 4-D extent -
>>> and how to
>>> we decide this.
>>
>> Seems to me that this is a question that would only occupy the mind
>> of
>> an extensionalist. Why the obsession with 4-D extents? There may be
>> many criteria of identity, surely, not just the spatiotemporal extent
>> of something.
>
> The reality is the other way around. Intensionalists write volumes
> about
> their search for criteria of identity (see Eli Hirst or David Wiggins'
> books) and offer a variety and analyse how they are unsatisfactory. (013)
Quite. Is that not what I just said, above? (014)
> For an
> extensionalist the matter is solved. What is odd (for me) about your
> position is that you do not seem to see any need to a criteria of
> identity,
> while arbitrary applying your own intuitive judgements on this. (015)
I do not think it is useful to engage here in a philosophical debate
about the merits or otherwise of identity criteria. One thing is
clear, that different people and communities will use many different
such criteria for many different, but to them compelling, reasons. It
is therefore not appropriate or useful to set out to impose any one
such discipline on the entire world of ontology users, no matter how
convincing one may feel that one's philosophical credentials are. IMO,
the responsible ontology engineering position should be to make these
explicit and try to find accurate ways to map between them or make
them at least mutually comprehensible, but not to make judgements
about their correctness or otherwise, since those decisions are
determined by criteria which lie outside the purview of ontology
engineering, such as in the history of a science or the practice of a
community. Hence my deliberate avoidance of this topic in these email
threads. What I think we can usefully do, perhaps, is to help people
state their identity criteria more clearly and explicitly; but even
there, my experience has been that they often have quite a clear idea,
and the apparent confusion arises from it not fitting into some
philosophical category. (016)
> Hence my
> comments.
>
> My use of 4d examples here is because you provided them as examples
> of your
> 4d intensional position - so I tried to find in that context
> examples of the
> issue.
>
>>
>>> So, for example, if we assume this Buddha weighs 100g, is
>>> there also a 100g 4-d object as well, and a 100g weight of Buddha,
>>> and a
>>> 100g weight of plastic, and so on. Without that what one has is a
>>> bit of a
>>> mess.
>>
>> One has a more complex picture of the world, but I see no reason to
>> justify the term 'mess'.
>>
>>>
>>> This is a serious practical problem for semantic interoperability in
>>> systems. To continue with the same example, if one system thinks
>>> there are
>>> two of more 100g weights there (and possibly more) and another
>>> thinks there
>>> is only ever one - they need to know they hold different views to be
>>> able to
>>> inter-operate.
>>
>> Indeed. DIfferent conceptualizations need to be aligned carefully for
>> just this kind of reason.
>>
>> Look, for practical ontology engineering purposes, I agree that the
>> 4D
>> view is preferable to the continuant/occurrent picture used in DOLCE,
>> in part for these reasons. But this is not to say that the DOLCE view
>> is *incoherent*. It is not. For some purposes, it is more intuitive,
>> in fact.
>>
>>> Or things would be even worse, if each system can arbitrarily
>>> decide how many things of what type there are.
>>>
>>> My guess is that the UoM work will need to arrive at, at a minimum,
>>> some
>>> local framework for this - if it is to make sense.
>>
>> I disagree. I don't think that UoM needs to get into these issues at
>> all.
>
> Well, let us see. For me the issue is whether people working on the
> UoM
> recognise they are getting into these issues, when they do. (017)
Fair enough; and I cannot disagree with that :-) (018)
Pat (019)
>
>>
>> Pat
>>
>>
>>>
>>>>
>>>> But as this discussion is completely irrelevant to the purposes of
>>>> this thread, let us drop the matter.
>>>>
>>>> Pat
>>>
>>> Chris
>>>
>>>
>>>
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