RDF for unstructured databases,RDF for axiomatic systems ?(was Re: [xml-dev] XML/RDF )

[Mike Champion <mc@xegesis.org>]

11/14/2002 4:20:30 PM, Uche Ogbuji <uche.ogbuji@fourthought.com> wrote:

>
>I should say that the project is proving a resounding success within Sun.  So 
>much for the idea that RDF is some academic oddity.


I think I am beginning to grok the RDF world a little better. Perhaps 
the problem (at least the motivation for the assertions/questions that triggered 
Uche's scorn) was that I had seen RDF through the lens provided by the rdf-logic 
effort and the Semantic Web vision, that is, as a way to define axiomatic systems 
on which machines will make interesting logical inferences about resources on 
the web.  For example, in the TimBL et al Sci Am article:

"Adding logic to the Web?the means to use rules to make inferences, 
choose courses of action and answer questions?is the task before the 
Semantic Web community at the moment. A mixture of mathematical and 
engineering decisions complicate this task. The logic must be powerful 
enough to describe complex properties of objects but not so powerful 
that agents can be tricked by being asked to consider a paradox...

An important facet of agents' functioning will be the exchange of "proofs" 
written in [RDF]".

That strikes me as highly unlikely to evolve, because a) it's DAMNABLY hard 
to build consistent and powerful axiomatic systems, especially about human 
affairs; b) logical inferences are extremely fragile in the face of ambiguity and
inconsistency, and the "solution" seems to presume profound breathroughs in
logic and/or computer science, and c) the "metacrap" issues: it's very clear that people 
(stupid, lazy, greedy, un-knowing of ourselves that we are) 
will not take the trouble to provide good and honest metadata for their content
unless The Boss is watching closely.  Not to mention the fact that few (e.g. the 
RSS users) want to pay the RDF tax, given its XML serialization that seems to 
have no friends at all except the RDF working group charter :-)

BUT perhaps I have been oblivious to the REAL users of RDF (and other 
semantic mapping technologies) who seem to use rough 'n ready ontologies (e.g. 
"<street>, <rue>, and <strasse> can be considered synonymous in an <address> 
context"), and those who use it as sortof an unstructured database for knowledge 
management applications. If one thinks of RDF queries as following chains of
"reasoning" that can ignore inconsistencies (I think Uche mentioned the
heuristic of using the first assertion) rather than as rigorous proofs
in a logico-deductive system, exploiting RDF's recursive subject-verb-object
structure common to most [all?] natural languages, then maybe some
interesting things can happen.

I'm still unpersuaded that very many HAVE happened.  We can all "refute" the 
claim that our favorite technology is an "academic oddity" by reference to 
a handful of proofs-of-concepts along with the assertion that this is the
tip of the iceberg or the start of something big.  (My favorite "academic
oddity" Next Big Thing candidate at the moment is Linda / tuple spaces / 
XML spaces ... it would be an interesting exercise to see if I could 
come up with as many success stories for this as an RDF stakeholder 
could for RDF ... <grin> ).  

Still, I wouldn't bet against a simplified RDF syntax 
(XML or otherwise) latching onto the "unstructured database" meme 
and growing into something Really Big.  That will end up
looking about as much like the Semantic Web vision as the HTTP/HTML web looks like
Ted Nelson's vision ... But what the hell, nobody ever said that evolution
favors the the most beautiful, only that it favors practical solutions to
real problems.