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Re: Thing and Class

From: Azamat <abdoul@cytanet.com.cy>
Date: Thu, 28 Aug 2008 10:58:51 +0300
Message-ID: <009301c908e3$e9018880$010aa8c0@homepc>
To: "'SW-forum'" <semantic-web@w3.org>, "[ontolog-forum] " <ontolog-forum@ontolog.cim3.net>
Cc: "James Leigh" <james-nospam@leighnet.ca>

As a devil's advocate, seemingly unsanctioned with the 3WC, Richard is doing 
a useful work raising sometimes justified objections for SW candidates 
looking for canonization (standardization).
As for James's reading of Thing and Class, it looks more as punning, 
possibly intentionally.

The interrelations of classes as well as classes and things are actually 
more subtle and deep, than generally presented in various specifications.
A member of a class may itself be a class. For example, the class of humans 
is a member of the class of species of animals. An individual human, even 
being a member of its class, is not a member of the latter one,  the class 
of species of animals. For a human is not a species of animal.
Whatever the number of human beings, it will not affect the number of 
species of animals. This goes as a kind of ontological rule of all 
taxonomies: whatever the number of instances, objects, particulars, it will 
not change the number of classes of things. Again, this means that 
relationships of class inclusion (subsumption) and class membership have 
some principal differences. Namely, the class inclusion is a transitive 
relation, while the CLASS MEMBERSHIP IS NOT TRANSITIVE. This fundamental 
fact is missing in some large scale, common sense ontologies, making the 
whole hierarchy just as invalid for computing applications.
Sum up: If Thing goes as the universal class, of which everything is a 
member, it will equivalent to Class, as the class of all classes. Other 
interpretations will be inconsistent, asking for many questions.

Hope this will be of use,
Azamat Abdoullaev

----- Original Message ----- 
From: "James Leigh" <james-nospam@leighnet.ca>
To: "Richard H. McCullough" <rhm@pioneerca.com>
Cc: "Semantic Web at W3C" <semantic-web@w3.org>
Sent: Thursday, August 28, 2008 4:30 AM
Subject: Re: Thing and Class

> Hi Richard et al.
> Here is an informal interpretation of some of the spec written in plain
> English.
> Class stands for classification.
> We use Class to classify things.
> Class is a set of Things.
> "I am a Human" - I just classified myself as Human (I hope I'm right).
> "I am a Thing" - that is true for everything.
> Human is a classification of all people.
> Thing is a classification of all things.
> Every Human is a Thing. Therefore Thing is a super set of Human.
> Is Human a Thing? No! its a Class!
> Everything Thing is an individual.
> Human is not an individual, it is a classification of individuals.
> Thing is not an individual, it is a classification of individuals.
> Can we classify Classes? Yes we can! Human is a classification - I just
> classified Human as a classification.
> Human is a Class.
> Thing is a Class.
> Are all Things Classes? No! I am a Thing, but I am not a classification.
> Is Thing the same as Class? No! Human is not a Thing, but Human is a
> Class.
> Hope this helps,
> James
Received on Thursday, 28 August 2008 07:59:37 UTC

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