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Re: [ontolog-forum] Current Semantic Web Layer Cake

To: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "Obrst, Leo J." <lobrst@xxxxxxxxx>
Date: Wed, 1 Aug 2007 18:42:48 -0400
Message-id: <9F771CF826DE9A42B548A08D90EDEA8002354C5D@xxxxxxxxxxxxxxxxx>
Aaargh. The real meaning of the symbolism is defined by its semantics.
The symbolism of a language, right? The symbols of a language. The
language has a syntax and a semantics. The syntax enumerates the
symbols and then gives the rules on how they can combine to form
expressions (sentences, groupings, etc.) The semantics is the
interpretation of those symbols and those syntactically legitimate
groupings of symbols (in a formal model).    (01)

This is formal semantics for formal languages.    (02)

Ontology is different. It is the content of a language (languages), or
equivalently is represented in the language(s). Most often this content
is called a collection of "non-logical constants", to set it apart from
the "logical constants" of the language (a logic is a language).     (03)

As such, the ontology content has formal models in that language
(languages), and those models are approximately constrained to be those
that the ontologist had in mind under his/her conceptualization of a
portion of the world. So, for example, an ontology that contains cars
and dogs will hopefully not license models which contain Fido and
JimBob's1957CandyAppleRedChevyTruck in the same set. The logical
ontologist is interested in formulating axioms (class/relation/property
and instance statements typically) about the content, e.g., Animal is a
Class, Person is a Class, the Person Class is a Subclass of the Class
Animal, etc. Subclass is a Transitive relation. Spouse_of is a
Symmetric relation. Part_of is more complex and is defined by a set of
(usually) mereotopological axioms that define Part_of by defining
Proper_Part_of, etc. These are "content" or "non-logical" axioms which
attempt to constrain the set of permitted models (allowed by the
semantics of the language) to a set of models that approximate the
conceptualization of the world that the ontologist had in mind.    (04)

This is formal ontology, or at least formal ontology refracted by
ontology engineering.     (05)

Is this clear as water or as mud?     (06)

This is why too often ontologists and logicians go at each others'
throats. (They both have large prehensile mouths that talk around each
other).     (07)

Formal ontologists have heartburn because they see "elephants" and not
sets. Their focus is on the things of the world, as opposed to the
things of language (logics, in particular).[1]    (08)

There are other definitions of "model". I am only talking about formal
models here. My guess is that those other definitions of "model"
largely lead back to this formal definition, whether those "modelers"
know this or not.    (09)

Thanks,
Leo    (010)

[1]  Languages (logics) have at least a bi-partite "model" (I hesitate
to say that): syntax and semantics. When you factor in stuff that we've
learned from the philosophy of language/linguistics, we think that
languages have a tri-partite "model": syntax, semantics, and
pragmatics. This stuff also suggests that for at least natural
languages (potentially formalizable as formal languages), there are two
notions (relations): 1) sense (a relation between the word and the
"semantic sense" or "word sense", e.g., "tank" as wordsense1, military
vehicle), and 2)denotation (what the word refers to once the sense is
chosen, in the real world). Pragmatics adds a third notion: what did
the user intend? I.e., semantics in context.
_____________________________________________ 
Dr. Leo Obrst       The MITRE Corporation, Information Semantics 
lobrst@xxxxxxxxx    Information Discovery & Understanding, Command and
Control Center
Voice: 703-983-6770 7515 Colshire Drive, M/S H305 
Fax: 703-983-1379   McLean, VA 22102-7508, USA     (011)


-----Original Message-----
From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
[mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Waclaw
Kusnierczyk
Sent: Wednesday, August 01, 2007 3:50 PM
To: [ontolog-forum]
Subject: Re: [ontolog-forum] Current Semantic Web Layer Cake    (012)

Christopher Menzel wrote:
>> The scopes and subject matters of Ontology and Logic shouldn't be  
>> mixed.
>> The real semantics or meanings of any symbolism or notation is  
>> defined by
>> ontology;
> 
> Silly me, I've been thinking that the real semantics of any symbolism    (013)

> is defined by, you know, its *semantics*.    (014)

silly you.  i have recently been introduced to a newly designed
language 
for summarizing the content of scientific publications;  when i asked 
about the semantics, the answer was 'the semantics are provided by the 
bioontologies'.    (015)

vQ    (016)

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