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Re: Monotony

From: Seth Russell <seth@robustai.net>
Date: Wed, 16 Oct 2002 10:04:41 -0700
Message-ID: <3DAD9C29.5050203@robustai.net>
To: pat hayes <phayes@ai.uwf.edu>
CC: fmanola@mitre.org, "www-rdf-comments@w3.org" <www-rdf-comments@w3.org>, "Patrick.Stickler@nokia.com" <Patrick.Stickler@nokia.com>

pat hayes wrote:

> The point is not that there are laws preventing you from saying 
> anything - clearly there are not - but rather than there are no 
> universally agreed WAYS to say this stuff, ie ways that are part of an 
> agreed standard. So it is unlikely that anyone else will know what you 
> are talking about. I agree that one can invent ways - you and Jos 
> DeRoos are two people who spring immediately to mind, not to mention 
> Tim B-Lee. BUt until we have one or more of these devices built into a 
> standard, i don't think that the world is going to just start adopting 
> any of these ways.

Well I doubt that RDF will be working for many people if everybody has 
to wait for the W3C to put their pet feature in a stardard before it can 
be deployed.   I've always though that  effective standards emerge from 
successful inplementations, rather than the other way around.    So this 
will work just as long as the W3C people don't go behind us saying "Tut, 
Tut .. you should not do that, it's not standard RDF".   Rather the W3C 
should recommend  mechinisms for us to register our user defined 
vocabularies.   

>>  If I publish a RDF document on the web, it certainly has a URI, and 
>> I certainly can say things about that resource (assumed here to be 
>> the graph) that has that name.
>
> True, but the RDF spec explicitly disavows any connection between the 
> thing denoted by a URI and the document located by that URI if it 
> happens to be a URL. I agree this is dumb, and I have no idea why the 
> W3C people are so insistent upon it, but that is the official position 
> at present.

Yes that is lamentable.  Topic Maps fair rather better than RDF in this 
regard.  But I don't see why we cannot progress in this direction in any 
case by defining  appropriate arc labels:  Something like ...

<DocumentA> <denotes>  <GraphA>.
<GraphA> <isRepresentedBy> <DocumentA>.  

Perhaps you could suggest an appropriate set of properties that we could 
start using ... huh, huh ?

>>  Why can I not say in RDF that this document (or cluster of ducments) 
>> either does (or does not) have the Closed World Assumption ?
>
> First, there is no way to refer to the document in RDF (see above), 
> but more seriously, there is no way to state a closed world assumption 
> in RDF, since RDF has no universal quantification. You could say it in 
> OWL, however. 

I have no problem with using OWL here.  

>> You may find  "Readings about the question: It is said that reasoning 
>> on the semantic web must be monotonic.  Why is this so, when human 
>> reasoning, which seems to have served us well, is nonmonotonic? "
>
> There is considerable evidence which suggests that human reasoning is 
> largely monotonic. (BTW, it is very tricky to argue about what 'human 
> reasoning' actually is. The fact is that we have very little idea how 
> human beings reason, including ourselves. One thing for sure, our own 
> introspections about how we reason are totally wrong; that much has 
> been clear for about 50 years now. )

Yep.  I think that human resoning (if it can be called reasoning) is 
more justification after the fact, than reasoning form fact to 
consequence.  

> But in any case, the key point here is that reasoning on the semantic 
> web is supposed to be done not by people, but by software. If people 
> were doing it then it would be the WWW, not the SW.

I think your wrong here.  I think that that the senario where RDF facts 
inform humans, then humans use those facts in their actions; will far 
outweigh the senario where automated agents actually perform logical 
reasoning from fact to consequence.  And even where the automated agent 
performs some task, it will seldom use logic programming to arrive at 
the consequence, rather it will use standard "if, then" programming.   
In fact, I believe the case you are purporting as the most common will 
actually be so rare, that there should be a prize given to the designer 
of such an agent.  

Seth Russell
http://radio.weblogs.com/0113759/
Received on Wednesday, 16 October 2002 13:05:24 GMT

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