[Top] [All Lists]

Re: [ontolog-forum] using SKOS for controlled values for controlled voca

To: ontolog-forum@xxxxxxxxxxxxxxxx
Cc: Graeme Hirst <gh@xxxxxxxxxxxxxx>
From: "John F. Sowa" <sowa@xxxxxxxxxxx>
Date: Tue, 12 Oct 2010 01:00:18 -0400
Message-id: <4CB3EB62.8000003@xxxxxxxxxxx>
Patrick, Graeme, Leo, Simon,    (01)

There are two totally different ways of using logic + ontology:    (02)

  1. Artificial mathematical systems:  Developing a system of formal
     logic and using it to define some kind of artificial system, over
     which we have total control.  An example would be some system of
     pure mathematics for which we have no applications in mind.
     Another example would be a some data structures inside a digital
     computer.    (03)

  2. NL semantics:  Describing some subject that people talk about
     in some natural language.  This includes every branch of science,
     engineering, medicine, business, politics, and the arts.    (04)

For anything in #2, the entities described by the ontology must
be related directly or indirectly to whatever people who use the
terminology refer to.  You can't claim that one notation (say SKOS)
deals with terminology and another one (say OWL) deals with ontology.
If they are using the same character strings for the same subject
matter, there is no difference.    (05)

> Graeme has another observation about language that may be of interest:    (06)

> This seems to arise from a combination of overenthusiasm for Western 
>scientific method
> and a misunderstanding of the nature of language that borders on fear. In 
>this view, language
> is a messy and highly imperfect medium that is not to be trusted, but rather 
>must either be
> sidestepped entirely or be beaten into submission by means of logic and 
>formalism.    (07)

> This seems like an anti-science and anti-logic quotation, I hope out of 
> It seems it is hard to be a computer scientist or engineer if you don't 
> in science and logic.    (08)

I think that Leo doesn't get the point that Graeme is trying to make.
My interpretation of Graeme's comment is that certain logicians, such
as Frege, Russell, Carnap, and Montague, were hopelessly misguided
about the nature of language and its relationship to logic.    (09)

I completely agree with that interpretation.  My three favorite
philosophers are Peirce, Whitehead, and Wittgenstein.  As logicians,
they were just as brilliant as the four above.  But they also had
a much deeper and more realistic understanding of the nature of
language and its relationship to the world and to the people who
use it to talk about the world.    (010)

In my paper "The Role of Logic and Ontology in Language and Reasoning",
I make the point that it is disastrously misleading to claim that the
semantics of NLs is *based on* logic.  Instead, it is more appropriate
to say that every version of logic and ontology that anybody has ever
proposed has been invented as an *abstraction from* NLs.    (011)

>  I don't think the answer is to throw our hands up and say
> "Oh, language is ineffable, inscrutable!"    (012)

I completely agree.  Peirce, Whitehead, and Wittgenstein would never
say that.  See my paper with quotations from them.    (013)

> Controlled Vocabularies are Controlled, in the same way that Controlled
> Natural Languages are Controlled...
> However, the constraints that are placed on the Terms permitted/the subset
> of syntax recognized require a certain degree of training before new terms
> can be added, or new sentences written.    (014)

I have been advocating CNLs for years. You can use CNL terms in
an abstract way when you're defining an artificial mathematical
system (point #1 above).  But when you're using logic plus ontology
for #2 (anything in the real world), the controlled vocabulary is
nothing more nor less than the labels for your ontology.  And it is
also a subset of the same terms that are commonly used in the field.
Some of the unused senses for each term might be disallowed in a CNL,
but people routinely do that with any NL.    (015)

> The important thing to remember is the KOS Concepts are essentially
> intentional-with-a-t.    (016)

You're making a distinction between prescriptive (intentional) vs.
descriptive (presumably more objective).  So what?  You can use NLs,
CNLs, or ontologies in either way.    (017)

> Controlled Vocabularies that allow Hierarchical relations must
> follow other constraints: the most important one is that the
> relationship must always be true. That means that if Term A has
> Broader Term B, everything that is about A must necessarily
> in some fashion also be about B. [Term == Concept in KOS speak].    (018)

That's fine.  But note the word 'about'.  That word is not
spelled the same as the logicians' word 'denote'.  That
indicates that they don't have the same meaning.    (019)

For example, the term 'paw' denotes a part of an animal,
not a type of animal.  But if you talk about a cat's paw,
you are talking *about* a cat.    (020)

The relation 'subtype', which is usually used in ontology,
is defined in terms of denotation.  The relation 'narrower',
which is commonly used in library science, is defined in
terms of aboutness.  Denotation and aboutness are not the
same.  Therefore, 'subtype of' and 'narrower than' are
not the same.    (021)

The fact that SKOS uses one term and OWL uses another means nothing.
You could introduce 'aboutness' as a primitive into OWL and use it
to define narrower-than.    (022)

> Of course there is a continuum working here, as is usual, but there
> can be discrete points in that continuum, which act as clarifying
> spikes or way-stations...    (023)

I certainly agree.  But the level of precision that is possible with
any subject depends on the application.  SKOS is more often used
with applications for which people make less sharp distinctions.
If you use OWL for the same subject, you can't make it any more
precise than you can with SKOS.    (024)

> there are typically clear differences between controlled vocabularies
> and thesauri, on the one hand, and ontologies, on the other.    (025)

No.  Look at medicine, for example, there is a one-to-one mapping
from the terminologies used by the physicians to the ontologies.
Patients, however, don't know the more precise terms.  So they
use vaguer words, and they don't observe the constraints.    (026)

> "Narrower than" is not the same as "Subclass of"    (027)

Of course not.  They are spelled with different character strings.
That indicates that they are different.  Note my comment to Simon.    (028)

So far, you have not given a single reason why SKOS can't be
considered anything but a subset of OWL with a different choice
of metalevel terms.    (029)

John    (030)

Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/  
Config Subscr: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/  
Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
Shared Files: http://ontolog.cim3.net/file/
Community Wiki: http://ontolog.cim3.net/wiki/ 
To join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J
To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx    (031)

<Prev in Thread] Current Thread [Next in Thread>