RE: SUO: Re: Ballot Comment - 3D versus 4D.
Pat,
. Thanks for this, with which I agree,
. What I am wondering are the particular implications you wish
me to draw from the 1st of the messages below. Could you please elaborate a
bit?
. Also, I'm afraid the Prolix reference went straight over my
head. I didn't find your message to Adam.
Cheers Graham Horn
National Data Standards Unit
Australian Institute of Health and Welfare
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Phone: 02.6244.1094
Fax: 02.6244.1199
Email: Graham.Horn@aihw.gov.au <mailto:graham.horn@aihw.gov.au>
-----Original Message-----
From: pat hayes [mailto:phayes@ai.uwf.edu]
Sent: Saturday, 1 September 2001 8:23
To: Horn, Graham; Matthew.R.West@IS.shell.com
Cc: standard-upper-ontology@ieee.org
Subject: RE: SUO: Re: Ballot Comment - 3D versus 4D.
>Dear Matthew,
> . Perhaps you're right.
>
> . Does this mean one can treat something as though it were 3-D
>for some purposes, especially short term ones, when it is really 4-D, the
>way we often do for convenience?
Let me break in here. This discussion illustrates the reason why using the
terms 3-d and 4-d is problematic. That isn't the issue. Of course there are
3-d things, and of course some things last through, or are extended in,
time, so are in a sense 4-d. Everyone agrees about that. The
incompatibilities arise from how to properly describe *changes* of
properties; notice I said DESCRIBE. Again, the facts are not in dispute: eg
Joes arm is longer in 2000 than it was in 1990.
The issue is, how is this to be DESCRIBED? Do we say that the thing Joes-arm
is extended in time, or do we say that it is 3-d and lasts through time?
Both would produce a 4-d geometry, viewed abstractly, but they would
DESCRIBE it differently; and the differences in what might be called
descriptive style are what produce the problems. The actual geometry of the
world is not in dispute; if that were all it were about, we could settle it
in a few minutes.
Pat Hayes
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-----Original Message-----
From: pat hayes [mailto:phayes@ai.uwf.edu]
Sent: Saturday, 1 September 2001 8:26
To: West, Matthew R SITI-GREA-UK
Cc: standard-upper-ontology@ieee.org
Subject: RE: SUO: Re: Ballot Comment - 3D versus 4D.
>Dear Graham,
>
>No you do not sometimes need to say things 3D and sometimes 4D.
>Even when you do not specfiy when the start of an extent is for
>a 4D object, it still has one (and has to have one) - it just
>isn't known.
>
>4D actually allows you to say more and less than 3D, as you
>require. It might help to think of it as a RISC rather than
>CISC instruction set. In 4D you tend to get more, simpler
>statements.
I think that is slightly overstated. It depends on the details. One does
often need to be more prolix in a 4-d account, and this has been used as a
criticism (eg see my message to Adam making the contrast with his example.)
Pat Hayes
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(650)494 3973 h (until September)
phayes@ai.uwf.edu
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