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Re: [ontology-summit] ontology as logical theory?

To: Ontology Summit 2007 Forum <ontology-summit@xxxxxxxxxxxxxxxx>
From: Chris Welty <cawelty@xxxxxxxxx>
Date: Sat, 27 Jan 2007 20:31:09 -0500
Message-id: <45BBFCDD.3050406@xxxxxxxxx>

[Against my better judgement, I enter the fray]    (01)

Chris-    (02)

An erudite argument, as usual.  But here is a logical theory:    (03)

(forall (x) (if (P x) (Q x)))
(P a)    (04)

This is the kind of logical theory you find all the time as examples in papers 
by 
logicians and by computer scientists who study properties of logical languages 
and 
algorithms for reasoning.  They don't give a hoot for what it means (what it 
refers 
to) - it is an *example* of a bit of logical syntax that lets me prove 
something 
about P, Q, and a. (and, in fact, if you ask them what P means, they will say 
"what 
difference does it make?")    (05)

Accepting ontology == logical theory trivializes ontology, IMHO. It is exactly 
the 
kind of thing I find myself fighting against time and time again.  It is the 
reason 
the FOIS conference exists.  I think its worth it to try and come up with 
something 
better.    (06)

When writing standards, you can make use of words like "must" "should" and 
"may" to 
convey less-than-perfect definition.    (07)

-Chris    (08)

Chris Menzel wrote:
> On Fri, Jan 26, 2007 at 03:51:32PM -0500, Obrst, Leo wrote:
>> I've changed the subject line of this message to better describe the
>> topic.
>>
>> In general, I tend to agree with you both concerning profligacy of
>> models -- but for logical theories. And it seems to me that ontologies
>> add (or subtract) something to that notion, i.e., their concern with
>> the real world *. And yes, I don't want to get into long philosophical
>> arguments either, amateurish or otherwise. And I know that "real" begs
>> the question. But I still think there is something crucial there. 
>>
>> I think one needs to use the best ideas, principles, analyses that
>> come out of formal ontology and formal semantics in the development of
>> (little o) engineering ontologies. For example, I think the OntoClean
>> methodology is an excellent step in the right direction, focusing on
>> meta-properties that semantically distinguish choices in the
>> subclass/is_a taxonomic backbone of an ontology. Similarly, the 3D/4D
>> distinctions and analyses that come out of formal ontology are
>> excellent for considering how you develop an ontology, as are notions
>> of intension/extension, possible worlds, etc., distributed/cumulative
>> readings, abstract individuals, fusion operators, interval semantics,
>> etc., from formal semantics. And to me, all these are rooted in the
>> real world. They are important precisely because they are tools that
>> try to help our understanding of some real domain **. 
>>
>> * Real world to my mind allows for conditionals, abstract realms,
>> fictional or dream domains or other cognitive states (internal
>> experience is still real experience). Mathematics to me is real, even
>> though not all mathematics is known. In a very real sense, I think
>> even mathematics is like science, partially empirically determined or
>> discovered. 
>>
>> ** One potential example: phlogiston theory. I think that it is or can
>> be a logical theory, even today. But is it an ontology? Nowadays, I
>> would say no, because it doesn't represent our best science of what is
>> real. Was it an ontology at one time: yes, quite possibly.
> 
> I am in general agreement with almost everything you say here, Leo, but
> I simply think your additional criterion for distinguishing ontologies
> from mere logical theories will remain so vague as to be useless and
> will, furthermore, generate needless controversy.  In this very post, in
> fact, it seems to me that your otherwise cogent post above illustrates
> the problem.  You note first that ontologies add something to logical
> theories, viz., "their concern with the real world."  The weasel word
> here is "concern".  What is it for a theory to concern the real world?
> Surely, on a relative natural understanding of "concern", phlogiston
> theory is, even today, concerned with the real world.  It provides an
> explanation for certain empirical phenomena concerning combustion (among
> others); it has simply been supplanted by a better theory that explains
> more without appeal to ad hoc fixes.  So "concern" must mean something
> stronger.  But what?  If you want to say that our current theory of
> oxidation count as ontologies, but phlogiston theory does not, then I
> can only think of two things that distinguish them -- it is simply (as
> noted) a *better* theory: it explains more.  So perhaps the idea is that
> a logical theory is an ontology if it is a better theory of its domain
> than any other theory.  But now the problem is that formal ontologies
> typically play no *explanatory* role at all.  What does, say, a wine
> ontology explain?  Explanation seems to me to be a role that only a few
> "elite" ontologies play.
> 
> So all I can imagine that you mean by "concerns the real world" is
> simply "true".  But surely that is *way* too strong a criterion; we have
> no way to guarantee that even our best scientific theories are true --
> it is reasonable to *believe* they are, but the history of science
> suggests that even very well corroborated theories can turn out to be
> false in important respects.  Moreoever, when it comes to ontologies of
> largely artifactual domains, like wine or automobiles, the whole issue
> of truth just doesn't have a lot of purchase, as the concepts that
> dominate in those domains are ones that *we* made up.  The test of
> quality for ontologies in these domains is not so much truth as the
> depth and accuracy of the manner in which an ontology represents the
> logical connections between the concepts in the given domain.
> 
> So I'm with John here.  A formal ontology is simply a logical theory;
> *any* logical theory.  This definition is completely clear and precise
> and cuts through all the generally useless haggling that results
> whenever anyone asks what an ontology is.  Moreover, I think it is an
> additional virtue that it cleanly separates what ontologies are from
> their quality -- and that's where all the action is, after all.
> Ontologies can be subject to a myriad of evaluative criteria.  Some are
> just silly (recall the Monty Python skit in which John Cleese (as Miss
> Elk) seriously proposes the "theory" that all brontosauruses were rather
> thin at one end, MUCH thicker in the middle, and then thin again at the
> far end :-); some are logically inconsistent; some are stronger than
> others (by notion or another of strength); some are finitely
> axiomatizable; and so on.  By trying to require that logical theories
> meet some further intentional, or epistemological, or metaphysical
> condition before they can count as fully-fledged ontologies seems to me
> turn "ontology" into a needlessly honorific title that invites
> controversy and unnecessary disputes -- who, finally, is the arbiter who
> decides what candidate ontologies shall deserve the title?  Much easier,
> it seems to me, is to level the semantic playing field here -- let every
> logical theory count as an ontology from the git go -- and let them all
> compete.  The best (read: most useful) will emerge as the survivors in
> the ensuing process of natural selection.
> 
> Chris Menzel
> 
>  
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-- 
Dr. Christopher A. Welty                    IBM Watson Research Center
+1.914.784.7055                             19 Skyline Dr.
cawelty@xxxxxxxxx                           Hawthorne, NY 10532
http://www.research.ibm.com/people/w/welty    (010)

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