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Re: [ontolog-forum] Ontology of Rough Sets

To: ontolog-forum@xxxxxxxxxxxxxxxx
From: "John F. Sowa" <sowa@xxxxxxxxxxx>
Date: Tue, 18 Jan 2011 21:09:37 -0500
Message-id: <4D3647E1.6020207@xxxxxxxxxxx>
Rich, Tara, and Chris,    (01)

I agree with Chris about the use of the term 'class' among logicians.
Although I like logic, I don't believe that logicians (or anybody else)
have the right to assign a technical meaning to a common word and expect
anybody else to use it (especially when it's used for a rather esoteric
distinction that most people are completely unaware of).    (02)

When I find words that are overloaded with too many common meanings,
I prefer to ignore them, and I would only use them in a technical
sense as part of a longer phrase.  That is one reason why I avoid
the word 'class'.  Unfortunately, there are too many popular computer
languages that adopted that term -- therefore, I have to use it when
talking about those languages.    (03)

RC:
> I prefer the type definition that is static, fixed in time.
> That applies if the class type is defined as a plurality of instances
> of the type definition, with optional class properties defined for
> association with the class definition as well.    (04)

Two problems with that definition:  (1) that's not how the word is
used in Java and OWL; (2) the number of instances may be large or
infinite, and there is no way to specify all of them except by
giving some rule or description for recognizing them.    (05)

That is why a type is usually specified by some rule or description
that can be used to recognize instances.  That is an intensional
definition that is independent of any change in the world, real
or possible.    (06)

John    (07)

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