Re: Ontology and Physics
I know you want a collection of low-level microtheories John. And you must
know I want a different perspective on the problem, an emergent perspective.
The fact we can't find a complete ontology does not mean a complete solution
is not possible. It just means it must be a different kind of solution.
I want a solution which prioritizes a process of finding structure, not
structure itself.
The emergent approaches to physics which are turning up in these discussions
-- Robert Laughlin, and now it seems "Process Physics" -- embody that new
kind of approach in response to incompleteness,... for physics. We can do the
same thing for ontology by treating ontology as a "process", a search for
structure, notably over language.
-Rob
On Tuesday 20 June 2006 22:38, John F. Sowa wrote:
> Rob,
>
> Thanks for the pointers to the articles by Chaitin.
> In particular, the lecture transcription is a very
> readable summary of a lot of ideas. At the end of this
> note, I selected a few excerpts I'd like to comment on
> (but I recommend the whole article).
>
> 1. One significant idea is that axioms are essentially
> a way of compressing a lot of data into a small
> number of general principles.
>
> 2. That gives a good way of viewing learning: it's
> a method of data compression that enables people
> to encode a broader range of knowledge than would
> be possible by rote memory of isolated facts.
>
> 3. But the various negative results, such as Goedel's
> incompleteness theorem, Turing's halting problem,
> and Chaitin's information-theoretic incompleteness,
> demonstrate that not all facts can be compressed.
>
> 4. However, the success of mathematics in science shows
> that a lot of important facts can be compressed.
> But trying to compress *everything* is impossible.
>
> This is just one more bit of theoretical justification
> for the point I've been trying to make: the hope of
> getting an ontology with detailed axioms for everything
> is wishful thinking. But it is possible to have a
> collection of low-level microtheories with detailed
> axioms for many important applications.
>
> In other words, the upper ontology should *not* have
> any axioms other than basic definitions, which just
> say how the types are related to one another. That
> would make it more of a taxonomy or terminology than
> what people have been calling an ontology.
>
> All the practical experience shows that this approach
> works: taxonomies and terminologies are very important
> for communication, for database systems, and for information
> retrieval. For deduction, the applications that have been
> successful are always very narrow, context-dependent cases.
>
> Doug Lenat and the Cyc group have come to this realization
> through 22 years of hard work. They had tried very hard
> to develop a top-down theory of everything, but they were
> forced to break it into microtheories. And Lenat has said
> that the upper-levels of the ontology are much less important
> than the context-dependent lower levels. There is no evidence
> that anybody else has a clue about how to do any better.
>
> John Sowa