Re: random thoughts on web logic

>In general I have a tough time with proposals that require the use of
>mechanisms such as the ones that Pat is proposing.

I wasnt aware that I had proposed any mechanisms. (I wish I  was able 
to.) Seems to me that I was only pointing out some problems which are 
going to arise and making some tentative suggestions for how to 
approach them. We will have to find SOME way to deal with them (or 
legislate them out of existence? Unlikely.). Tim B-L has made some 
similar comments, I've since discovered (see 
http://www.w3.org/DesignIssues/Inconsistent.html)

>I have a hard enough
>time trying to figure out monotonic, certain representations without adding
>certainty factors, probabilities, etc., etc., even for small examples.
>For large examples, with many objects, assertions, classes, knowers, etc.,
>the situation becomes, to me, hopelessly complex.

If the web seems "hopelessly complex" to you, Peter, then you maybe 
should be working on something else. But in any case, I wasn't 
advocating the use of certainty factors or probabilities; I was just 
giving an exposition of a basic idea about nomonotonicity.

>Of course, it is possible that someone will present a logic that makes it
>easy (easier?) to perform this kind of representation.  But without such a
>logic, and I mean a full logic, including semantics, deduction, and
>algorithms, I don't see how one could in good faith propose these
>mechanisms as a vehicle for representing information that will be acted on
>by agents that do not have the level of ``common sense'' that we ascribe to
>human beings.

Im not sure that this kind of debate is useful, but let me just 
register some optimism in response to your pessimism.  I think we are 
all agreed that we can't expect agents to just 'have' common (or any 
other kind of) sense, which is why we want a logic which can embody 
some of that stuff so that agents can transmit it and utilize it to a 
limited extent.  Being a good oldfashioned logical type, I'm all for 
good oldfashioned logics (as 'full' as we can manage), but I think 
that we will need to modify our old ideas about semantics to 
accomodate to the web's messiness. In particular, we have to come to 
terms with the fact that logical names arent just logical constants 
any more (ie essentially skolemised existentials) but can cross-refer 
to other places over which we have no control (and may even get used 
in 'nonlogical' ways, eg as words in NL text.). We will have to be 
able to deal with the fact that inconsistencies will arise involving 
assertions from disparate sources, and the processes of resolving 
them may need to take into account the nature of these sources and 
some kind of notion of their warrantability. These are just facts 
about the web and the way it is already used in B2B and P2P 
applications which we need to come to terms with. So instead of 
complaining about how loose and ill-defined this stuff is, I think 
that people with a logical training have some new fields to conquer 
here, and I'd like to encourage us to get on with it rather than 
complain about a 'lack of logic'. Its our job to try to help get a 
suitable logic invented, right? Now, got any good ideas?

Pat Hayes

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Received on Tuesday, 26 September 2000 13:25:35 UTC