W3C home > Mailing lists > Public > www-rdf-interest@w3.org > February 2001

Re: does RDF require understanding all 82 URI schemes?

From: David Megginson <david@megginson.com>
Date: Mon, 12 Feb 2001 11:15:49 -0500
Message-ID: <14984.3125.160043.977784@localhost.localdomain>
To: www-rdf-interest@w3.org, xmlschema-dev@w3.org
Dan Connolly writes:

 > > Clearly, it hasn't worked
 > 
 > Huh? I use it all the time; so do lots of other folks.  It works
 > fine. What problem(s) are you referring to?

The lack of any critical mass of implementation -- there's a lot of
software, but very little data outside a few dedicated research
projects and the popular but very narrowly-specialized cases of
RPMFind (run by a W3C staffer in any event) and RSS (note, by the way,
how little code is shared in software for those two projects).  XML in
general on the Web has also failed by the same measure, though (like
Java) it has had great success behind the scenes on the server side.

 > As if Tim B-L is the only one who believes that the Web
 > should work like it does?

No, but he's the one with the big club (the ability to veto any W3C
spec he disagrees with), so he matters an awful lot more than the rest
of us.

 Lots of people expect that
 > the best place to find info about
 > 	http://example.org/foo#bar
 > is, in fact, http://example.org/foo#bar

Who owns the thing being discussed?  Let's say that I want to publish
information about the Battle of Jutland.  If I use the identifier

  http://www.megginson.com/battles.rdf#jutland

I've left anyone else who wants to describe the same battle with a
choice between two miserable alternatives:

1. use the same identifier, and eternally privilege my information
over anyone else's; or

2. use a different identifier, and lose any easy possibility of
collating the information.

Yech.

 > > no one's statements
 > > should be privileged,
 > 
 > Why not? If you want to know what my favorite color is,
 > surely an answer from me is privileged over an answer
 > from, say, someone who hardly knows me.

That's a question that can be answered only on a property-by-property
basis -- you're a reasonable authority on your favorite colour, but
the W3C is a better authority on whether you're in its employ, and
WWW10, on whether you're a speaker.  Subjective statements (Dan
Connolly is/is not intelligent, good looking, interesting, a good
coder, etc. etc.)  rightly belong to no single authority, though we'd
be likely to privilege *any* other authority over the person himself.

In summary, it probably makes sense to treat
http://www.danconnolly.org/about.rdf as an authority for the specific
case of Dan's favorite colour, but not for many other things.
Encouraging resolution of RDF resource identifier URIs is wrong for
the general case.

All of these problems arise even with something -- a living human
being -- that has an obvious, legally-enforceable identity.  Many
(most?) of the things we'll want to describe in a data-based Web --
ideas, historical people/places/things, etc. -- don't even have that.

 > Er... I'm looking at piles of robust, interoperable software
 > that uses URIs in this fashion.
 > http://www.w3.org/RDF/#developers
 > http://www.w3.org/XML/Schema#Tools

I've written a couple of big chunks of it, and I'm afraid it's neither
robust nor interoperable, though I've done my best.  The inability to
round-trip a Namespace URI is the killer.


All the best,


David

-- 
David Megginson                 david@megginson.com
           http://www.megginson.com/
Received on Monday, 12 February 2001 11:18:03 GMT

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