Re: NPR, Godel, Semantic Web

[John Cowan <cowan@mercury.ccil.org>]

Mike.Champion@SoftwareAG-USA.com scripsit:

> The first is a Semantic Web use case I remember from somewhere, and the
> second is Goldbach's Conjecture, a (possibly) "true but unproveable"
> assertion often used as an example of a "Gödel sentence."  

An example of what *might* be a Goedel sentence: nobody knows for sure.
If it is unprovable, it has to be true, because if it were false,
there'd be a counterexample, which would mean it wasn't unprovable.
Still, lots of people thought Fermat's Last Theorem was unprovable too.

> Could it be
> that the "semantic web" as an axiomatic system will not be rich enough to
> contain arithmetic, but could be rich enough to perform any practical
> inference of use to us?

The Prolog inference system doesn't contain arithmetic, only finite-field
arithmetic, which is much weaker.  And yet useful work is done
in Prolog.

-- 
John Cowan                                   cowan@ccil.org
One art/there is/no less/no more/All things/to do/with sparks/galore
	--Douglas Hofstadter