Hi Pat --
I hesitate to debate with such a distinguished logician as yourself.
However, what about SQL? Much of our commercial and scientific life depends
on it, and it undoubtedly uses negation as "failure to prove".
Are you saying that we should move all commercial databases to a different
query language using classical negation?
Cheers, -- Adrian
Internet Business Logic
A Wiki and SOA Endpoint for Executable Open Vocabulary English over SQL and
RDF
Online at www.reengineeringllc.com Shared use is free
Adrian Walker
Reengineering
On Wed, Jun 25, 2008 at 11:06 PM, Pat Hayes <[EMAIL PROTECTED]> wrote:
> At 8:37 PM -0400 6/25/08, Adrian Walker wrote:
>
> Hi John --
>
>
> Allow me to respond also.
>
> You wrote...
>
> *It's important for us to develop Common Logic as the growth path
> for ontologies and to incorporate CL in the Semantic MediaWiki.
>
> Anything currently represented in either the Semantic Web notations
> or relational databases can be mapped to Common Logic. And the
> more compact CL notation is vastly more efficient in storage space,
> transmission time, and computation time than the current Semantic
> Web notations.
>
> We should position CL as the foundation for Semantic Web 3.0.*
>
> You may like therefore to address Chris Welty's point that CL appears
> infeasible for the W3C rule interchange project. In slide 11 of [1], Chris
> says:
>
> *The CL and IKL approach [is] deprecated: infeasible for this group [W3C
> Rule Interchange], as major differences appeared irreconcilable (e.g.
> non-mon vs. mon)*
>
>
> He is there referring to a particular* approach*, viz. to adopt a highly
> expressive language into which all rule languages can be translated, which
> was used in the IKRIS project which produced IKL. If however you read on in
> the same slides, you will find that the language finally adopted as the
> initial Rule standard, though much weaker than CL, in fact is a classical
> logic with a classical negation, just like negation in every other logic
> with a clear semantics.
>
> The fundamental difficulty seems to be
>
>
> That isnt the* fundamental* difficulty for RIF.
>
> that CL and IKL have chosen a theoretical semantics for negation
>
>
> Its not especially 'theoretical'. It is simply what negation means in
> ordinary language. If you say cows are white, and I say, No, cows are brown;
> then my "no" says that what you said is false. That simply is what negation
> * means*. This is a common-sense, pre-theoretical notion of negation.
> So-called 'negation as failure' is the theoretical notion, and it only
> arises from database theory. The basic snag with negation as failure is that
> it is almost always* not valid*. It is simply* wrong*. The cases where you
> can validly infer, from a failure to prove P, that P is false, are extremely
> rare. They only occur in specialized circumstances in specialized tasks
> performed by specialists in certain limited cases. Can you prove that every
> finite abelian group can be expressed as the direct sum of cyclic subgroups
> of prime-power order? Answer quickly. Suppose, just for the sake of
> argument, that you can't. Are you justified in concluding that this is
> false? Maybe you had better hedge your bets.
>
> from before the computer era, whereas SQL and most logic based programming
> languages use a different meaning for negation -- one that can also be
> formalized, e.g. as in [2].
>
>
> It can be formalized, for sure. It can in fact be formalized in many
> different, incompatible, ways. All of them however make it vividly clear
> that this is not a generally correct inference rule.
>
> Pat
>
>
> Thanks for your thought about this.
>
> -- Adrian
>
> [1] http://ontolog.cim3.net/file/resource/presentation/ChrisWelty_200806
> 12/W3C-Rules-Interchange-Format--ChrisWelty_20080612.ppt
>
> [2] Backchain Iteration: Towards a Practical Inference Method that is
> Simple
> Enough to be Proved Terminating, Sound and Complete. Journal of Automated
> Reasoning, 11:1-22
>
> Internet Business Logic
> A Wiki and SOA Endpoint for Executable Open Vocabulary English over SQL and
> RDF
> Online at www.reengineeringllc.com Shared use is free
>
> Adrian Walker
> Reengineering
>
>
>
>
> On Mon, Jun 23, 2008 at 10:54 PM, John F. Sowa <[EMAIL PROTECTED]> wrote:
>
>
> Peter,
>
> Thanks for posting the audio for Mark Greaves talk. I wasn't
> able to log in for the talk, but I read the slides. The audio
> covers some important points that are not in the slides:
>
>
> http://ontolog.cim3.net/cgi-bin/wiki.pl?ConferenceCall_2008_06_19
>
> The Semantic MediaWiki is very important work, and since it is
> available as open source, we should use it.
>
> But one important point that Mark mentioned is that the reasoning
> capabilities of current Semantic Web technology is very weak.
> RDF(S), OWL, SPARQL, and RuleML are useful, but weak subsets
> of Common Logic.
>
> It's important for us to develop Common Logic as the growth path
> for ontologies and to incorporate CL in the Semantic MediaWiki.
>
> Anything currently represented in either the Semantic Web notations
> or relational databases can be mapped to Common Logic. And the
> more compact CL notation is vastly more efficient in storage space,
> transmission time, and computation time than the current Semantic
> Web notations.
>
> We should position CL as the foundation for Semantic Web 3.0.
>
> John
>
>
>
>
>
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