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Re: [ontolog-forum] Time representation

To: <ontolog-forum@xxxxxxxxxxxxxxxx>
From: <matthew.west@xxxxxxxxx>
Date: Fri, 25 Jan 2008 11:43:20 -0000
Message-id: <808637A57BC3454FA660801A3995FA8F0645536D@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Dear Pat,
At 8:33 PM +0000 1/24/08, Chris Partridge wrote:
I have cut out some irrelevant stuff.

>>I think this is where ontology (as a picture of reality comes
>I don't follow. Why would it come in here more than in designing
>software? Surely you aren't thinking of ontologies as new scientific
>theories (are you??)

There is a long tradition of regarding computer systems as theories.

As *scientific* theories? 
MW: No. It was you that introduced the word "scientific". 
I will
give you the quotes if you wish.

Jonathon Lowe (a philosopher I recall you meeting) has a technical
definition of ontology as "the set of things whose existence is acknowledged
by a particular theory or system of thought." (E. J. Lowe, The Oxford
Companion to Philosophy)

He is clearly using the word in its philosophical sense, not its IT sense. Nobody in this forum is doing philosophical ontology. 
MW: How would you distiguish his use of the word "theory" from the meaning that you would ascribe to it in a computing sense? 
Taking these two points together, one can regards a computer system's
ontology as (roughly) "the set of things whose existence is acknowledged by
a particular computer system"

Im not sure what that means, but its certainly not ontology as in 'ontology engineering'. 
MW: In what way is it different? In what sense is the set of things that a system will let you hold information about not its ontology? If it is not its ontology, what is it?
>>When we reflected upon this, what we realised is that we had tried (and
>>succeeded to an extent) in capturing the main features of corporate
>>- and that the new (unrecognised) situations were just (very) unfamiliar
>>combinations of familiar features.
>You were lucky!

The issue for us was that this became a regular feature, so it seemed to be
more than luck.

I meant, you were lucky that you only had to go around the knowledge extraction loop once. 
MW: Perhaps, but it might also be skill in the knowledge extraction process that enables the "fruitfulness" that Chris refers to.
>That seems on the face of it to be self-contradictory. Isnt it pretty
>much the definition of 'unforseen' that one cannot plan for it ahead
>of time, since it is invisible?

I think there is a difference between saying that we can foresee that we are
going to do USD/GBP currency exchanges - and how we plan for that in a
And saying that the financial markets are volatile, and new instruments are
going to arise (whose details we do not know) - and how we plan for that. At
some level, we are saying that we cannot foresee what is going to happen.

Right. So how is it possible to plan for something that you cannot forsee, other than in a general sense trying to stay alert? 
 MW: After your response to Pat C advising him to favour an ontology of time that did not make a commitment to a continuous or granular view of time, exactly the kind of fruitfuness in design Chris and I are advocating, I am surprised that you would say that. Fruitfulness in design, for me, has a lot to do with not closing off possibilities unnecessarily. This is not so much a matter of forseeing future requirements, as designing, in a way that allows what is possible.
>>One way of doing this is to try and make
>>the design reflect what is actually happening reasonably accurately
>?? Surely that is exactly what one should not do, in order to be able
>to handle unforseen situations. That strategy will lock in the way
>things are at the time the system is designed, not the way that
>things might become later.
>>  - one
>>way of testing this is to see how fruitful the design is.
>How does one set out to do that? This sounds about as clear as
>testing a design for 'elegance' or some other unmeasurable subjective

I do not understand. The test is reasonably simple and has clear results. If
you want details you can read the book. What is immeasurable or subjective
about it?

I need to read the book, obviously, but I suspect we are at cross purposes. I cannot even imagine what would be a simple test of success at solving an unforseen problem. Unforseen by who, when? Suppose it turns out to be able to do something unforseen, but the designer then tells you they had in fact forseen that and planned for it. Who is to contradict them? 
MW: Yes, I think you  are at cross purposes. I suspect that one of the problems here is that you would take what I would call fruitful design as obvious, but it is not so frequently practised. A good test of fruitful design is that it does not make any statements that are not true under all circumstances (in any context to bring together two threads). It is precisly this that makes a piece of ontology portable, reusable, and hence fruitful.
But in any case, why has this got anything much to do with ontology design? Do you feel that ontologies should be designed for unforseen things more than other artifacts? 
MW: I think you are getting too hung up on this unforseen thing. It is not the main point, reusability, flexibility, and extensibility are the results of fruitfulness, whether or not you can forsee all the consequences that this might bring. The kind of behaviours that lead to this are not placing constraints at a higher level in the ontology than they truly reside, just because other parts of a larger ontology are not part of the requirements this time - one of John Sowa's hobby horses, and another way of saying what I said above, about making statements that are true in all circumstances.


Matthew West
Reference Data Architecture and Standards Manager
Shell International Petroleum Company Limited
Registered in England and Wales
Registered number: 621148
Registered office: Shell Centre, London SE1 7NA, United Kingdom

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Email: matthew.west@xxxxxxxxx

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