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Hi Thomas,
Thanks for the quote. I think that in front of this issues attitudes are
possible
a) Say that it is incompatible.
b) Offer several ways to resolve it
Actually, it seems that the semantic web is based on a single type of logic.
However, several ontology resolution mechanisms are possible
a) Possibility Theory expanding on fuzzy set theory
b) Probability theory
b) Simple Boolean logic (the one actually used by W3C)
c) Multiple valued logic
As you can notice, the world is complex, our knowledge incomplete and
evolving, this is why we may need more than one logic to based the semantic
web.
Boolean logic leads to a whole or nothing view of the world. I just went
through the W3C wine OWL sample and I got a good laugh. Imagine, wine, a
topic with so diverse point of views, so many different possible ontologies.
It's funny to see that one example used by W3C is precisely one that would
benefit from more than simple basic whole or nothing logic.
What if we could choose our logic and ontology resolution mechanism? I can
still remember when protégé made possible to use several problem solvers for
a particular ontology; previously a tightly coupled system prevented that.
Taking W3C example, we may have two wine experts and two corresponding
ontology. We can reject both since they are incompatible and say that
according to a Boolean logic this leads to an exclusion principle, a
standard way could be made available to resolve the issue differently.
According to John Sowa there are two kinds of ontology:
a) Formal
b) Prototype based.
It seems that W3C is taking the path of formal ontology based on Tarsky work
about model theory. What about a prototype based ontology which will
probably be the real life ontology of the web? I personally think that
formal ontologies are too costly to be used at the web scale and it will
probably be very limited to small groups with special needs. Prototype based
ontologies are more adapted to emergent and evolving knowledge. We just have
to look at the recent progress made on Adaptive Object Model to see that
models, ontologies are evolving at the rhythm of our knowledge evolution.
Are there any discussion, links, and pointers leading to that direction at
W3C?
Cheers
Didier PH Martin
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