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Re: [ontolog-forum] Role of definitions (Remember the poor human)

To: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Kathryn Blackmond Laskey <klaskey@xxxxxxx>
Date: Wed, 14 Feb 2007 21:04:03 -0500
Message-id: <p0611043ac1f95892d908@[]>
Bill,    (01)

>...An earlier note of yours mentioned "classification".  I suspect 
>this is how you, being a machine learning person, view the role of 
>"ontologies".    (02)

I think that may be the first time I've been classified as "a machine 
learning person."   :-)    (03)

As for my view of the role of ontologies, I posted a note on this 
forum a couple of weeks ago a note discussing uses of ontologies. 
That note didn't mention classification.    (04)

>Some quick questions, then.  If "ontologies" are supposed to include 
>sophisticated mechanisms for handling probability distributions    (05)

I think ontologies should be able to include information about 
probabilities, and this ability needs to be supported by ontology 
languages.  I'm not sure what "sophisticated mechanisms for handling 
probability distributions" means.  Ontologies don't "handle" things. 
They represent things.    (06)

>and are supposed to support classification,    (07)

I'm not sure what you mean by "support classification."  Any ontology 
that includes a type hierarchy "supports classification" in the sense 
that it specifies the types into which objects can be classified and 
the attributes that can be used by a classifier.    (08)

Adding the ability to express probability information to an ontology 
would improve its ability to "support classification."  But 
ontologies are not classifiers. The primary purpose of most 
ontologies is not to "support classification."    (09)

>then what would be the role of epistemology and phenomenology in 
>such ontologies?    (010)

I'm not sure what you are asking here.    (011)

It seems when I say ontologies ought to be able to include 
probabilities that some people automatically think I'm confusing 
ontology and epistemology.    (012)

Do you think the Dirac probability rule in quantum theory is 
epistemology and not ontology?  What about inheritance probabilities 
in genetics?  What about the sensitivity and specificity of a very 
well-characterized diagnostic test for a medical condition?  What 
about the detection probabilities for a radar system? Emission 
probabilities for a radioactive substance?    (013)

These kinds of probabilities are well-grounded in physics.  I will 
grant that there are strict subjectivists who maintain that all 
probabilities are subjective.  But for some phenomena, probability 
distributions are grounded in physical law and are as 
well-established and well-characterized as anything we know about the 
world. As of the early 20th century, the laws of physics are 
fundamentally probabilistic at their core.    (014)

I find it very difficult to swallow that the type hierarchy for the 
parts in Company X's parts catalog -- something defined by convention 
and that can change any time Company X decides to reorganize its 
parts catalog -- is ontological, whereas radioactive emission 
probabilities are relegated to epistemology.    (015)

>Do they all get rolled in?    (016)

An ontology represents the types of things that exist in a domain of 
application, the attributes entities can have, and the relationships 
in which they can participate.  I think that when relationships are 
probabilistic, and the probabilities are well-established and 
well-characterized aspects of the domain, then those probabilities 
belong in a domain ontology.    (017)

I think that purely subjective probabilities that are grounded in 
nothing other than someone's opinion do  not belong in an ontology 
intended for shared use by a community.  Of course, if somebody 
chooses to use a probabilistic ontology language to formalize his 
personal probabilistic theory of a domain, no one can stop him, just 
as they can't stop him from writing an idiosyncratic OWL ontology to 
which nobody but he subscribes.  In fact, the languages developed for 
the purpose of formalizing shared domain knowledge may turn out to be 
very useful for formalizing the opinions of individuals.  But I would 
use the label "ontology" to mean a repository for well-characterized 
domain knowledge agreed upon by a defined community and shared widely 
among practitioners of the community. I think the kinds of 
probabilities I described above pass that test.    (018)

>Is it the case that you reject the traditional divides between 
>ontology, epistemology, phenomenology, and semantics in natural 
>languages?    (019)

No, I do not reject those distinctions.    (020)

I should point out, though, that ontologies are intended to represent 
what "really is out there", but they are not THE SAME AS "what is 
really out there."  The very fact that we do not agree on our 
ontologies is proof that our ontologies contain representations that 
are not fully faithful to what they represent.  Analysis of the 
relationship between a formal ontology and that which it represents 
belongs to the field of epistemology.  Right?    (021)

Kathy    (022)

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