On Aug 7, 2009, at 12:31 PM, Mike Bennett wrote: (01)
> John and Chris,
>
>> God rarely testifies on the witness stand.
>
>
> I think the insurance companies are still looking for him.
>
> Seriously though, I've been trying to get to the bottom of this
> business
> about 3D/4D incompatibility assertions, and the apparently related
> issue
> of extensional versus intensional definitions and why they go
> together,
> and I'm picking up clues in this exchange but would like to know if
> I've
> understood it right. Is it about the ability to define a state of
> being
> intensionally, versus having to go back in time to an event in order
> to
> define that state of being extensionally?
>
> I've always assumed that a definition is (by definition!) intensional,
> whether that definition is a written one or a set of logical
> statements
> about what it is to be a member of that class. If an extensional
> definition is of the form "all the States in the USA", then surely you
> are describing an extent, not defining a thing (the definition would
> be
> framed in terms of what it /means/ to be a State). In any case I
> wonder
> if that sort of extensional description can be framed for every kind
> of
> Thing? Similarly if a role type has an extensional definition like
> "all
> the people who are customers of X", then the state of "being a
> customer" would require an intensional definition - does that put the
> concept of "being a customer" outside the scope of what can be defined
> in an extensional ontology? Unless, perhaps, you go back in time and
> observe them /becoming/ customers? Is that the issue here?
>
> I'm trying to work out if this is where the perceived need for a 4D
> ontology comes in. I've yet to see a 3D ontology. (02)
In the sense we are (I hope) using it here, OBO and DOLCE are both
examples of 3D ontologies. In fact, if anything, this style is more
common than (what we are calling) 4D. Both of them treat time, of
course, and things being extended in time: but the 3D style insists
that some physical things, called 'continuants' - roughly, objects as
opposed to events - are inherently 3D in their nature, have no
temporal extent or temporal parts, but rather retain their identity
*through* time. These ontologies also typically admit 'occurrents'
which are more like 4D things, in that they have a real temporal
extent and can have temporal parts; but such ontologies insist upon a
sharp, exclusive top-level distinction between these two categories,
which are thought of as 'embedded' in time in different ways. In
particular, an occurrent is inherently a 3-D entity which 'continues'
to exist as time passes, and is *not* a 4D entity. In Simon's phrase,
it is wholly present whenever it is present. This means that one is
obliged to distinguish for example Pat Hayes the continuant, who is
typing this message *now* and is the same Pat Hayes who will exist
when you are reading it in the future (the present when you actually
read it, of course), from a very similar entity which might be called
Pat Hayes' life-history, which is genuinely extended in time and has
parts called Pat's childhood, Pat on his sixteenth birthday, etc..;
this latter being an occurrent rather than a continuant. At any moment
in my life, there is a rather intimate connection between me-the-
continuant and what might be called the time-slice of my history at
that moment; but, importantly, this relationship cannot be identity,
since two of these history-slices at different times are necessarily
distinct things, whereas I am the very same - identically the same -
person-continuant throughout my life (even though, of course, my
properties may change: which is why, in a conventional formal
ontology, they must be treated as what McCarthy called *fluents*, ie
as having an extra temporal parameter.) (03)
A lot more has been written on this idea, but I hope this is enough to
persuade you that the notion is not entirely incoherent, though IMO it
is severely flawed and the 4D framework is superior. My point in
reply to Chris was only that strict extensionalist identity criteria
can be used in either this or a 4D ontological framework, and indeed
can be translated between them: essentially the same criteria can be
stated using either ontological framework. (04)
> The world as we know
> it has things which have an extent in space and time, and have mass,
> charge, temperature and so on - the basic dimensions of the "good
> enough" Newtonian physics we all learnt at school. So that's what I'd
> expect to model in an ontology. (05)
But not all ontologies need be about the physical world; and even
those that are, need not conceptualize it the way that physical
sciences do. As many folk in this forum will attest, our own human
language carves the world up in ways that do not make scientific sense. (06)
> If a given application is only
> interested in things at the current point in time, then the implied
> ontology of that individual application will clearly be a 3
> dimensional
> (or less) ontology. But as soon as we start to define an ontology that
> can work across a whole business unit or supply chain, one would
> want to
> start asserting facts in different dimensions, especially time, in
> order
> to disambiguate terms. (07)
Of course; but (3D plus time) need not mean 4D. One could characterize
the 'continuant' framework in fact by saying that it effectively
refuses to allow continuants to be embedded in time *considered as a
dimension*. In this, I would add by way of keeping an open mind on the
subject, it is in common cause with some current theoretical
physicists, who have been casting doubt on the very notion of time
being a dimension like space: see for example Lee Smolin's
entertaining book "The Trouble with Physics". (08)
> For example, a bond has an interest rate, and as
> far as one application is concerned, that interest rate is "obviously"
> (i.e. contextually) the interest rate right now, while to another
> application it's just as "obviously" the interest rate defined when
> the
> bond was issued. For a bond with a variable interest rate, one of
> those
> is a number and the other is a formula for determining that number.
> Creating an ontology that goes beyond one part of the business
> workflow
> obliges us to take account of the time dimension in order to
> disambiguate terms that were meaningful only in the implied 3D
> ontologies of individual systems.
>
> If you set out to define a comprehensive model of "how things are"
> then
> I would argue that you need some kind of lattice of basic types of
> thing
> that partition the model - continuant v occurrent, independent v
> relative and so on - and I accept that these need not be the same
> partitions or that any one partitioning is "right", though the above
> two
> are pretty fundamental even if they are not explicitly stated in a
> particular ontology.
>
> There is a question of terminology as to whether these top level
> distinction are framed as "things" (Continuant Thing and so on) or
> "partititions" in the UML sense (Continuant v Occurrent maps neatly to
> the UML Structural versus Behavioural partitions), or as something
> else,
> representing a kind of ontological commitment or a theory, and I think
> people sometimes talk at cross purposes about what sits at this top
> level of most ontologies. In defining an ontology with a Continuant
> partition, one is making an ontological commitment to the existence of
> classes of "Thing" which exist at some period in time and therefore
> necessarily have a beginning and an end (09)
No. A continuant can be eternal. (010)
> - and therefore of course a
> commitment to the 4th dimension. (011)
No again. Time need not be a *dimension*. In the case of a continuant,
it is logically required to NOT be a dimension: continuants *do not
have* a temporal extent, by definition. (012)
> Like people, roles, states (in the
> USA), states (in state diagrams) etc. There are things outside that
> partition, that do not continue to be, but simply happen - events,
> state
> transitions and so on. Then you have one, mutually exclusive and
> completely exhaustive pair of partitions. Continuant things continue
> to
> be, even if they change over time, as surely they must. (013)
Careful. Their *properties* change, but they do not change, in a
sense. They retain their identity: they are the **same** thing at
**different** times. This is not 4D: it does not even make sense in a
4D framework. (The same thing exists at various times but does not
have a temporal extent? If that seems incoherent to you, then you
probably think in 4D; but then you really should not be using the
continuant/occurrent terminology.) (014)
>
> All of which is both 4 dimensional and intensional. By using a lattice
> of theories, one can define the partitions of a model in terms of the
> ontological commitments made towards the "God's eye view" as novelists
> call it, of what are the intensional definitions we are going to
> give to
> things. This would cover as many things as are of interest to the
> application or business, in as many dimensions are are relevant. I
> don't
> see any reason to deny that to the ontology modeller.
>
> Then for example the concept of ownership is a concept which can exist
> within such an ontology, and can be given an intensional meaning -
> written and/or with properties, e.g. ownership must always have an
> autonomous, self-directing being that does the owning, and a thing
> which
> is owned. You might also model the temporal event of coming into
> possession of something, but the state can be defined intensionally
> without that, surely.
>
> In other words I don't see why there is any need, practically or
> conceptually, to go back in time to some event which brought about the
> state so described, in order to be able to define the state as a
> state. (015)
I wholly agree. Does anyone maintain the opposite view? (016)
Pat H. (017)
> Sometimes it is of practical use and relevance to the target
> application(s) that you connect events in the past with states in the
> present or at some other point in time, for example to model the
> relationship between a legal event or ceremony and a legal state.
> However, I don't see any reason why this should be a necessary
> pre-condition of being able to model the thing at all, if indeed
> that is
> what is being suggested. Just as an event has a cause whether we
> know it
> or not, so a continuant thing has a beginning whether we know it or
> not.
>
> Chris: Does the need for a (specifically extensional) 4D approach
> follow
> from the extensional approach, and if so how does it differ from the
> 4+D
> approach implicit in most intensional ontologies? For instance the
> Units
> of Measure work is proceeding just fine in creating intensional
> definitions in all the dimensions in which we can measure things.
>
> On a more practical note, is there some fundamental dichotomy of
> theories that would sit /above/ the lattice of theories of a
> multi-dimensional intensional ontology, to distinguish if from a
> BORO-style extensional ontology? Can this theoretical dichotomy be
> dissected in such a way that two ontologies, one in each of these
> styles, can be related to one another, or are terms in extensional
> ontologies not reusable? I'm thinking in terms of what sort of meta-
> data
> can be defined about an ontology or its terms or partitions, that can
> help people in different domains identify and reuse ontology material
> that has definitions for terms that are of interest to them. If we can
> formalise the relationship between these approaches, perhaps we can
> formalise the required meta-terms?
>
> Mike
>
> John F. Sowa wrote:
>> Chris,
>>
>> The term 'Cambridge property' was introduced by Peter Geach in the
>> derisive phrase "mere Cambridge property" without giving a
>> definition.
>> Barry Miller (in the Stanford page you cited) gave a definition:
>>
>> A Cambridge property is the referent either of a relational
>> predicate or of a purely formal predicate.
>>
>> That's fairly clear, but it's at the level of Quine's dictum:
>> "To be is to be the value of a quantified variable."
>>
>> I use the term 'role type' for a very widely used type of word
>> or concept that everybody uses daily:
>>
>> Author, Player, Spouse, Buyer, Seller, Pet, Employee, Manager,
>> Contractor, Pilot, Driver, Mathematician, Brother, Sister,
>> Student, Weed, Nuisance, Tool, Prize, Reward, Favor, Example...
>>
>> CP> However, I can easily give an extensional definition of them
>>> - if the role of the definition is to capture the extension...
>>
>> The primary role of a definition is to tell people how to use
>> the term in a way other people will understand. None of those
>> words can be defined by observable properties of the individual.
>> The same plant, for example, could be a weed or a delicacy,
>> depending on somebody's intention.
>>
>> Brother and Sister are two of the easiest to define, but note
>> that there may be only one person in the world who actually
>> observed the relevant conditions, and you have to take her word
>> for it. The 4-D proponents usually reply "Yes, but somewhere
>> in that vast infinity of space and time, the relevant events
>> really do exist."
>>
>> CP> "For example, if I buy a car, the car does not change in any
>>> observable way." One can, of course, observe the process of
>>> buying.
>>
>> How do you observe it? By watching someone go to a car dealer
>> and negotiate? By watching the buyer go to an auction and
>> raise a hand at the appropriate moment? By seeing somebody
>> typing away at a browser connected to the Internet? Even
>> if you saw those events, how would you know that the buyer
>> didn't sell the car or the repo man didn't tow it away?
>>
>> Since car ownership is registered by the government, there are
>> more reliable methods than observing the act of buying. But
>> very few things anybody owns are ever registered in that way.
>>
>> For things other than cars and houses, it would be far more honest
>> to use the traditional way of stating the criterion: "God knows."
>> Unfortunately, when you need proof of ownership, God rarely
>> testifies on the witness stand.
>>
>> John
>>
>>
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>>
>
>
> --
> Mike Bennett
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> (018)
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