Re: godel-like incompleteness of relational model

In message <6%_qc.6458$NK4.656343_at_stones.force9.net>, Paul <paul_at_test.com> writes
>mountain man wrote:
>>>>>And what is the problem with The Relational Model?
>>>>
>>>>It has a Godel-like incompleteness:
>>
>>http://www.mountainman.com.au/software/history/relational_model_incompl
>>ete.htm
>
>I don't quite understand what you mean here. Even if you think that
>relational theory is missing something, I don't think it is a
>"Godel-like" incompleteness.
>
>>>I'm no mathematician, but didn't Godel prove that 'any' formal system
>>>is incomplete?
>> Yes, he did. But I am being specific about provision of one
>>specific
>> instance in which the incompleness of the RM is comprehendable.
>
>Well, Godel acually proved that first-order predicate logic (upon which
>the relational model is based) is complete in some sense. The
>Incompleteness theorem only applies to theories that are above a
>certain complexity. To add to the confusion, there are slightly
>different meanings of "complete" here. See this page for more details:
>http://www.sm.luth.se/~torkel/eget/godel/completeness.html

And isn't there something about if they are complete, then they also have to be simplistic (and therefore cannot be real-world accurate)?
>
>I think essentially the difference is that you need to use logic to
>show that some other theories are incomplete, but to show the
>completeness of logic itself you've got a bit of a self-referential
>paradox. I could be completely wrong here though. Very interesting though.
>
Cheers,
Wol

-- 
Anthony W. Youngman - wol at thewolery dot demon dot co dot uk
HEX wondered how much he should tell the Wizards. He felt it would not be a
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The Science of Discworld : (c) Terry Pratchett 1999