Re: Cross-ontologies reasoning

Folks, it seems to me that there is altogether too much pessimism 
being expressed on this topic. The fact that 'cross-ontology 
reasoning' poses problems is undeniable, but ask yourself what the 
reason for it has been. If you take two people and tell them to 
formalize ontologies describing some domain, without communicating 
with one another, the chances are close to zero that they will 
produce formally compatible ontologies.  Until now this has been the 
normal way to proceed, and the results have been predictable. But it 
seems to me that the advent of the semantic web, simply by placing 
ontologies on the WWWeb in public view, will in itself provide a 
practical cure.  Already, the sane way to approach writing an 
ontology is to first check to see if there is one already written 
that you can use, perhaps with some modifications. If there is not, 
you write your own: but even then, if you find that you need a 
concept of, say, AUTHOR, then it is easy to check to see whether 
someone already has a suitable notion formalized, or even simply 
registered, and to use that one in your ontology also. The Dublin 
Core terminology is widely used for example and has thereby, from 
this wide use, acquired a formal meaning which one could not actually 
derive from the 'defining' ontology itself (which in this case 
consists of little more than a vocabulary with English comments): the 
very act of 're-using' a term in another ontology *in itself* adds to 
the global suite of formally described information about the concept. 
In this way, the SWeb can, I suggest, become a kind of evolving, 
growing global ontology representing a large-scale consensus, rather 
than a huge collection of independently written ontologies requiring 
constant human intervention to translate between them.

This optimism depends of course on thinking that people will re-use 
concepts in this way. But the real reason for optimism is that there 
is no reason not to do this, and every reason to do it.  Human 
language evolved because it is useful to be understood and to 
understand: the ability to communicate benefits both ends of the 
communication channel. So writers of ontological content for the 
SWeb, and users (readers) of that content, will all feel the economic 
pressure to re-use existing content as far as possible, so that they 
can be understood and can understand one another. All this pessimism 
seems to me to be like worrying that if people were all to invent 
their own language, communication would be very difficult. Which is 
true, but only relevant if there is any reason to think that people 
are likely to do that: and there isn't.

Pat Hayes
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Received on Friday, 19 December 2003 21:16:57 UTC