Nonmonotonic rules

Re. the (forever ongoing and interminable) debate about the merits of 
otherwise of nonmon reasoning.

Bottom line: nonmon reasoning is brittle (by definition) but can be 
very efficient. So when you know it won't break, by all means use it. 
But it seems to me that it is up to its proponents to justify or 
explain how we can have nonmon formalisms being used in a Webbish 
context, where the brittleness (or if you prefer, 
context-sensitivity) seems on the face of it to be an unsurmountable 
barrier to deployment, since there is no way for a reader of some 
nonmon rules to know what the intended context is; and when used out 
of context, nonmon rules are almost always wrong, and can produce 
potentially dangerous errors. (Note, this is only referring to the 
*publication* of nonmon rules on a Web, not to their *use* in some 
application where it is known they are appropriate, or one is willing 
to take the risk of using them in any case.)

So far, the only response Ive heard on this point is a kind of 
blustery denial: a claim that the Sweb just isn't going to be like 
the WWWeb, but more like an intranet, where all the users will just 
know, or will be told by the owner, or will agree among themselves in 
managers' meetings, which worlds are closed and which namespaces 
satisfy the unique-names assumption and so on; so the problem will be 
avoided by what might be called Web-external contextual agreements. I 
refuse to take this answer seriously: it seems to me to just be a 
statement to the effect that one is not working on the semantic web 
at all.

Anyone got any other answers? Until someone has, I would suggest that 
all talk about nonmon systems be ruled out of order.  Its not enough 
to observe in a general kind of way that nonmon systems are useful 
(no argument) or that they are in widespread use and all the best 
companies have them and they make a lot of money (irrelevant) or that 
they solve this or that famous problem (they usually don't, in any 
case). There is a basic technical issue that needs to be addressed. 
Address it, or else please shut up about them.

Pat

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Received on Thursday, 15 January 2004 15:29:07 UTC