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Re: [ontolog-forum] FW: Next steps in using ontologies as standards

To: "'[ontolog-forum] '" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "Patrick Cassidy" <pat@xxxxxxxxx>
Date: Mon, 12 Jan 2009 12:08:01 -0500
Message-id: <075e01c974d8$53328eb0$f997ac10$@com>


   Yes, F=ma is only a *theory* of motion, and as I have mentioned in this thread, incompatible theories would have to be maintained in some extension(s) to the basic FO.  Sets of concepts that are mutually dependent on each other for their description would have to be located together – whether in the base FO or in some extension to it.  I was pleased that Matthew brought up the case of mathematically described concepts, and this issue applies to many “derived” units of measure such as acceleration.  But in some cases that may appear to be co-dependent, one of the elements such a “force” may also correspond to a more basic concept, and be properly in the base FO as a true primitive.  Force can be directly perceived by the sense of touch, and things that make direct sensory impressions have, in my view, a privileged status as prime candidates for primitiveness.  The physical equations relating to force are not restricted to its effect on acceleration, but also include things like the compression of a spring, and the intensity of pressure due to force on a compressible fluid.  So I think that “Force” would be a true primitive, though “F=ma” would have to be in a ‘theories of motion’ extension, along with Einstein’s equations.  Although the unit of force is a “derived” unit in the SI system, the effect of force can be directly perceived, and this is a good reason (I think) to consider it a primitive. “force” is also one of the words in the Longman defining vocabulary.

   The exact inventory of physical units of measure that should be in the basic FO would have to be decided by the consortium constructing it.  I have not gone through the list to determine whether all of the current SI units (meter, kilogram, second, ampere, kelvin, mole, candela) are the only units that belong in the base FO.  The coulomb, for example, used to be considered as one of the base units (of electrical charge), but is now considered as a derived unit (one amp-second).  I would want the coulomb to be in the base FO, but there may be arguments against that. If they are considered non-controversial, I would hope that the consortium decides to include derived units as well, for convenience.  Perhaps if all the non-controversial derived units were maintained in one extension, it would be almost as convenient. 

    I think that a principle for construction of the FO should be to include everything that is desired by someone, as long as it is logically consistent with the rest.  If it is clearly a derived concept (not primitive as defined by the consortium), and is clearly relevant to some restricted domain, then the consortium *may or may not*  decide to move it to that domain extension, even over the objections of some contributors.  This reflects the practical need to resolve disputes quickly.  The issue of what is or is not a primitive may  have to be resolved by majority vote in some cases.




Patrick Cassidy



cell: 908-565-4053



From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Olken, Frank
Sent: Monday, January 12, 2009 11:08 AM
To: [ontolog-forum]
Subject: Re: [ontolog-forum] FW: Next steps in using ontologies as standards


Pat Hayes and Pat Cassidy,


These statements are only true for "Newtonian" conceptualizations of time.

Relativistic models of "space-time" require the specification of both spatial and

temporal locations.  Relativistic temporal models arise in astronomy, astrophysics,

high energy physics. 


In a purely computer science context see the classic paper by Leslie Lamport

on Time, Clocks, and the Ordering of Events in a Distributed System,

Communications of the ACM, vol. 21, no. 7, p. 558-565, July 1978



                    Frank Olken



From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Pat Hayes
Sent: Sunday, January 11, 2009 11:51 AM
To: [ontolog-forum]; Patrick Cassidy
Subject: Re: [ontolog-forum] FW: Next steps in using ontologies as standards


On Jan 11, 2009, at 10:18 AM, Pat Hayes wrote:

When you say “Those various temporal theories can all be expressed in terms of three concepts: time-point, time-interval and duration.” , what do you mean by that?  Is being “expressed in terms of” used only for necessary and sufficient definitions?


No, I mean only that each theory uses only those three terms, or can be reformulated using only those (or in some cases only two of them.) Of course, since the theories have different axioms, they assign somewhat different meanings to them. 



Thinking more, this isn't really accurate. They all use only these three classes, but they also use various different relations, such as the timepoint and subinterval orderings and the various relations between points and intervals. So perhaps the typical number of concepts is more like six or seven than two or three.



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