W3C home > Mailing lists > Public > www-rdf-logic@w3.org > October 2000

Re: names, URIs and ontologies

From: pat hayes <phayes@ai.uwf.edu>
Date: Tue, 31 Oct 2000 17:16:31 -0600
Message-Id: <v0421010db624fd420ab6@[]>
To: Seth Russell <seth@robustai.net>
Cc: www-rdf-logic@w3.org
Seth Russell <seth@robustai.net> wrote:
>pat hayes wrote:
> >  In http://www.w3.org/DesignIssues/Webize.html, Tim seems to
> > be  focussing on the issue of 'webizing' in the sense of making sure
> > that when c uses "foo" (in a purely private sense) and d also happens
> > to use "foo" in a similarly private way, that everyone else doesnt
> > get these two private uses confused with each other.
>Pat you are confusing me.  I though TBL was saying that if anyone uses
>a URI with  _my_ namespace prefix (example:
>names:robustai.net/chiggy#foo), then they are asserting that they are
>talking about the exact same thing that am talking about when I use
>that URI.  It doesn't matter where in the Web they record their
>message, or who records it.

Right, that is my understanding also, and I have no problem with 
that. The namespace prefix disambiguates the local "foo". However 
there is an additional assumption, which is that unless someone has 
explicitly asserted an identity, one cannot infer that 
uwf.edu/phayes#foo is referring to the same thing. Now, for "foo" 
that might be wise: but for "Boston" it is a pity not to take 
advantage of the fact that you and I (let us suppose) were indeed 
using that as a *name*, not just as a local identifier. More 
particularly, it is a pity that one cannot declare that some 
identifier is *intended* to be used in a more public way. I might 
want to use "Boston" in a way which assumes that it has the same 
meaning as a whole lot of other uses of the same name, without having 
to mention them all.

>And the plan is for people to try to use
>URIs from standard namespaces for our common public concepts as much
>as possible.

Now, that is the part of the plan which seems mysterious to me. Where 
are these 'standard namespaces' to be found? Who will provide them? 
Name spaces have never (until now) been provided by anyone: they have 
simply arisen within groups of language users. I am sure they will in 
fact continue to arise in much the same way on the web, and I want 
the DAML logic to be able to reflect and reason about this kind of 
phenomenon. But if my use of "foo" is guranteed to be in a different 
logical namespace than your use of the same name, just by being 
located at a different URI, how can these common namespaces ever get 

Just for clarification, it is important to realise that while 
ontologies can be used to define the meanings of concepts, they 
cannot possibly define the referents of proper names. How could one 
*axiomatize* the meaning of a word like "Boston" , or "Wales" , or 
"Seth_Russel" ?

>Please, somebody, correct me if I am operating under a
>misapprehension.  Pat, If this is true, wouldn't you have exactly what
>you want?

If there were a public namespace mechanism in place, it might well 
be, yes. But I do not see how it can be created by external fiat, I 
think it must somehow arise from use. I would like to understand how 
it can possibly be made to happen.  (I am a beginner in this area, so 
if this idea has been already developed by all means point me at what 
I should read.)

>I think this Semantic Web Plan works only in as much as we *do* use
>common URIs; to the extent that everybody makes up their own URIs to
>talk about their own private matters, we don't have a semantic web at
>all; we would just have the tower of babble to which you refer.

But consider: people do in fact use names to refer to things, even on 
the Web, and they do not in fact often get confused about references. 
Human society has always functioned in this way, and we do not live 
in a babel.

>If my assumptions are correct (sheeze i hope they are) this still
>means that one will probably encounter many different URIs for the
>same concept.   Pat, does this problem bear on your concerns?

Yes, centrally. More particularly, if I want to refer to something in 
a way which will be understood by others, how do I find the 'standard 
namespace'? And if I do not find it, how will I be able to convey my 
meaning to anyone else?

>  The
>only solution I see to that problem is for each local application of
>the Semantic Web to install some kind of fuzzy node matcher that would
>attempt to combine nodes that are really the same, based upon their
>relationships to literals and other known nodes.  In combining nodes
>the applications could preserve all the original URIs and the sources
>from which they were originally read.  Then when the application wants
>to speak RDF to those sources, they could use the URIs which that
>source will recognize.  See my signature for an example.

This is an excellent idea. (However I bet those would get awfully 
long for something like "Boston".  :-)

>topic: Seth Russell
>URI:  http://robustai.net/~seth/index.htm
>email: seth@robustai.net
>waiting for:  RSS
>is working on:  MyMemory
>needs collaboration on: MyMemory
>topic: RSS
>anagramOf: (alternative: Rich Site Summary, RDF Site Summary)
>URI (from source: http://rss.oreillynet.com/): http://purl.org/rss/
>URI (from source: http://InternetAlchemy.org/):
>URI (from source: http://www.xml.com/):
>topic: MyMemory
>description: "a local application of the Semantic Web"
>hasAbilityTo: (and:  (read RdF) (write RDF))

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Received on Tuesday, 31 October 2000 18:13:11 UTC

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