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Re: [ontolog-forum] Difference between XML and OWL

To: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: "John F. Sowa" <sowa@xxxxxxxxxxx>
Date: Thu, 23 Oct 2008 23:19:54 -0400
Message-id: <49013EDA.8010201@xxxxxxxxxxx>
Ed,    (01)

I also believe that we have many points of agreement, but there
are also many more issues that have to be considered.    (02)

EB> We came at this from different viewpoints, with different
 > prejudices, and the clarifications have revealed that we have
 > reached many of the same conclusions, which may only mean that
 > we are both wrong on some points.    (03)

Everybody is wrong on many points.  But when people who come from
different perspectives reach similar conclusions, there is some
hope that there is a common core that has a more general validity.    (04)

EB> Bounding computational complexity is the big rationale for
 > Description Logic and all of its variants, and the key criterion
 > for admissibility of extensions and variants in the DAML->OWL
 > program, and many related Semantic Web activities.    (05)

I disagree with the first line.  As I said before, the original
DLs were derived from work by Ron Brachman (1979) and his thesis
adviser Bill Woods (1975).  The main motivation for Bill's work
was not computational complexity, but the need for finding a
more rigorous logical foundation, and Ron continued that trend.
Computational complexity was not their main interest.    (06)

Two other streams that flowed into the DL river were the very
informal, but practical work on frame systems and Aristotle's
original syllogisms.  I gave a brief summary of those issues
in the introduction to the book _Semantic Networks_, which I
edited and which included contributions from several communities
that used network notations.  The DL community, the conceptual
graph community, and several others were represented.    (07)

In the conference from which that book developed, it was clear
that the DL community had two distinct branches:  a practical
group that had strong roots in frames and computational methods
(LOOM and PowerLOOM by Bob MacGregor et al. were examples) and a
theoretical group that focused on proving that their algorithms
were tractable.  I believe that both sides would have benefited
from more collaboration with the other.    (08)

EB> The methodology part for OWL and friends is only beginning
 > to emerge, and I don't think it was a target of the DAML->OWL
 > program.  Methodology development based on the "common upper
 > ontology" approach is probably the dominant form in FOL land,
 > although I don't doubt there are others.  And I understand
 > "compiler-based methods" to refer to logic programming, a la
 > Prolog, JESS and Jena, which is certainly knowledge engineering,
 > but entirely different from "ontology development" a la OWL or
 > CLIF in my view.    (09)

OWL is a tool.  And creating a design and development methodology
for a particular tool is, in my opinion, bass-ackwards.  The work
on methodologies began in 1945 with the flow-charts by Goldstein
and von Neumann.  In the 1960s, the work on methodologies merged
with the pre-computer systems and procedures methods for analyzing
work flow that included the people and the business procedures as
well as the data processing hardware and software.    (010)

In the 1980s and '90s, John Zachman developed a very broad framework
for Information System Architecture (ISA) that encompassed everything
in an enterprise.  I collaborated with Zachman on a joint paper that
summarizes some of the issues:    (011)

    http://www.research.ibm.com/journal/sj/313/sowa.pdf    (012)

That paper talks about everything in the enterprise, which includes
much more than a specific tool.  It includes all the people, employees,
customers, products, processes, locations, and data processing methods,
equipment, etc.  There is not just a single type of chart or diagram.
Figure 6 shows 30 boxes with 30 different *types* of diagrams and
the interrelationships among them.    (013)

The Unified Modeling Language (UML) consists of multiple diagrams
for representing various aspects of a project in a way that is
independent of any particular tool.    (014)

EB> Actually, the people who do that are building "ontologies" for
 > Vampire or Otter or some other FOL reasoner.  And their mode of
 > expression is some FOL language in the CLIF/KIF family.    (015)

No!  Vampire and Otter are just two more tools.  Zachman's ISA
encompassed the all the tools and everything else in an enterprise.
The Semantic Web should encompass at least as much as Zachman
considered more than 20 years ago.    (016)

EB> And all of this engineering is "programming", in the sense that
 > it is building a software machine to solve a set of problems.    (017)

The ontology has to be as broad as Zachman's ISA.  From that broad
resource, a programmer can derive (using various design and development
aids, including knowledge compilers) solutions to specific problems.    (018)

EB> The main contribution of the DAML research was to find maximal
 > combinations of the published extensions that produced in toto
 > a still computationally bounded algorithm.    (019)

You're talking about algorithms for teeny-tiny problems.  Just
designing a single airplane involves an enormous number of very
different kinds of problems.  And an enterprise for designing
and building airplanes (which was one of Zachman's major examples)
is far, far larger.  And the whole world is even bigger.    (020)

EB> But what does occur in practice is the reasoner running for an
 > hour without a result, and there being no way to know whether it
 > would find a result in 6 more minutes, or 6 more days, or never.    (021)

Oh piffle!  For over 60 years, programmers have successfully debugged
programs that got hung up in loops, and they didn't need somebody
to restrict their language so that they can't write loops.    (022)

EB> As ugly as it may be, the OWL effort is making a lot more people
 > aware of what can be done, and of course, encountering problems
 > like these.    (023)

Absolutely not!  People are using OWL as a very primitive kind of
logic-programming language.  At VivoMind (and many other companies
that know what they're doing), we download whatever RDF and OWL
we get into Prolog, which gives us an industrial-strength language
that runs circles around OWL in both performance and ease of use.    (024)

A methodology for a single tool such as OWL is a major step backwards
from UML, from Zachman's ISA, and even from the pre-computer systems
and procedures methodologies of the 1950s.    (025)

If the Semantic Web is ever going to live up to the hype, it will have
to be much broader than a single enterprise, and it will have to include
everything that is described by any and every type of UML diagram.
Zachman didn't have any training in logic, but he had a much broader
vision of a methodology for design and development that went far beyond
a single tool.    (026)

John    (027)

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