Hi
I think there are several, quite seperate ideas and assumptions here which need making explicit, if we want to be sure we are all talking about the same thing.
Two approaches to codifying knowledge have been discussed. In the classical philosophy of ontologies (as championed by Ed) there is a kind of 'perfect' external world of atomic facts which the ontology seeks to accurately represent. Once the back-breaking labour of building this knowledge base is complete, the hope is that all useful queries become analytically solvable. This idea has dominated predicate logic reasoning approaches in orthodox AI for more than 50 years.
The fuzzy, tag-cloud approach of Flickr et al. takes a totally different approach. The knowledge structure is not built by design or careful construction. Instead, the continuous amalgamation of millions of autonomous individuals making personal, biased decisions allows differentiation of links based on popularity. If a link between two concepts is useful, then it tends to be spontaneously generated by more people. The tag cloud simply sorts by popularity. This is the same guiding principle that Google uses - if your page is popular, then that means many people want to access it. Therefore, it is important.
It seems to me that this list is in general working to the following specific assumptions:
Whether these assumptions are reasonable is a matter for discussion on this list. My personal view is that static ontologies are likely to be of limited usefulness in a field where concepts are ill-defined, in a constant state of flux, and are often subjective. I question the assumption that knowledge in astronomy is made out of atomic facts. And I don't think the maintainability problems will go away by liberal sprinkling of aliases or probablistic 'might-be-a' relationships. As an earlier poster pointed out, the strength of ontological reasoning is derived entirely from the rigourousness and precision of the concepts defined. Sacrifice that, and all queries will return the equivalent of 'here's some things you might be interested in' - which is where we already are.
It's not my intention to be negative or confrontational. I appreciate that these are works in progress, people are committed to different approaches etc. It's likely there excellent counter-arguments to the issues I've raised. I think they should be made explicit. A bit of clarity would certainly help me understand the viewpoints others here hold!
Cheers
Eric
On Mon, 5 Mar 2007, Ashish Mahabal wrote:
>
> This is getting very Godelsk.
>
> The aliasing mechanism provides for consistency. We could thereby miss some
> truths. We can only hope that we do not miss any interesting ones.
>
> Flikr, blogspot are inconsistent systems in that A would define SN as
> something and B would define SNe as something else, but C may presume them to
> be the same. All will be happy, but at least one will be wrong.
>
> -ashish
>
> Ashish Mahabal, Caltech Astronomy, Pasadena, CA 91125
> http://www.astro.caltech.edu/~aam aam at astro.caltech.edu
>
> Gods do not protect fools. Fools are protected by more capable fools.
> -Luis in Larry Niven's Ringworld
>
Received on 2007-03-06Z11:28:07