Hi Azamat and Chris,
Shame on those who claim that Thing can be
a Class and an Instance at the same time! Only multiple inheritance
modelers would even face that issue in the first place. I am not a C++
The Delphi VCL classes descend from TClass
and TObject separately. TObject is not an instance of TClass, so that
every instance of TClass is an actual TClass, and every instance of a TObject is
a TObject, and ne’er the twain shall hook up.
Only refinement processes tease out the
actual classes and instances. A program comprises a graph of refined
classes and each class has a suite of instances, varying in time of creation
and destruction as to definition of each instance at time t.
But its messy to use iterations of any
kind of instances if you cant discern the difference between a class and an
instance. Those infinities can be pesky, but they sure show up in the
Restrict your database to entities
(dynamic) and properties (static) and you can organize it better. Expand
into philosophically interesting directions and get problems. The choice
is clear to me.
Rich AT EnglishLogicKernel DOT com
9 4 9 \ 5 2 5 - 5 7 1 2
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Christopher Menzel
Sent: Monday, January 17, 2011
Subject: Re: [ontolog-forum]
Ontology of Rough Sets
On Jan 17, 2011, at 5:00 PM, Rich Cooper wrote:
Only the individuals and instances are
You appear simply to be asserting
your own personal views as if they were self-evident, eternal truths. The whole
issue of what is or isn't "real" is a tremendously vexed issue and
it's far from clear that any deep metaphysical commitment to this or that
fundamental philosophical ontology has any useful role to play in ontological
engineering at all — on which point see the recent, very interesting
debate between Gary Merrill and Barry Smith/Werner Ceusters. But regardless of
where you come down in that debate, nearly every useful ontology in
existence takes things other than individuals as "real" —
notably, the classes that populate any OWL ontology.
Perhaps you prefer that I use the term
“classes” instead of the term “sets” in that no class
can contain itself as an element.
The class THING (or whatever you call
the most general class) contains itself as an element in many ontologies.
And I thought you just said that only individuals and
"instances" (whatever those are supposed to be) are real. What are
you doing talking about classes?
constraint leaves us free to use the individuals, instances of data types, as
the model of ground truth. In that representation, classes are groups of
individuals, instances, et cetera. Using that representation, the
equivalence function could be composed on any or all of the four class types
– rough, fuzzy, probabilistic and crisp.
This is much too vague for anyone
(well, me) to know what you are claiming. (This is not a request for more
opinion, it is a mistake to construe sets as containing themselves,
This is like saying it is a mistake
to construe numbers as "negative". It is obviously not a "mistake" to allow
non-well-founded sets; simply broaden the universe of sets beyond the
well-founded sets of ZF set theory and they are (provably) just as respectable,
theoretically. There are, moreover, many useful applications of
non-well-founded sets. Perhaps you prefer not
to avail yourself of non-well-founded sets; knock yourself out. Others find
mathematicians have invested heavily into that interpretation.
There are a relative few
mathematicians who study them and others who have found useful applications of
them. I know of no reasonable sense in which "mathematicians have invested
heavily" in them.
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