uri crisis – what do URIs identify?

Still, we don’t use the Semantic Web in broad and I think one problem is, that we don’t find the right uris to identify ideas/people/things – concepts from the real world. The discussion about the URI crisis does not happen in conferences and articles, but everytime somebody proposes a new uri scheme to identify books, lifescience terms, etc. Then masses of people flame each other on mailinglists.

There are nifty approaches about to cure the identity crisis (like this here) but they all fail the problem because the problem is much deeper.

I usually then write one email saying “uri crisis again” to point out that the problem is unsolved.

So, what is the Uri crisis about?

basically, this text TimBl has written describes it best:

What does “http://www.amazon.com/exec/obidos/ASIN/0679600108/qid=1027958807/sr=2-3/ref=sr_2_3/103-4363499-9407855

  1. A whale
  2. “Moby Dick or the Whale” by Herman Melville
  3. A web page on Amazon offering a book for sale
  4. A URI string
  5. All the above

When was the thing it identifed last changed?
Have you read the thing it identifies?

it is part of the article “what do HTTP Uris identify?”

So we don’t have good uris to identify people, concepts, books, etc. Because a Uri has more than one meaning.

This is explained very good by David Booth’s article
“Four Uses of a URL: Name, Concept, Web Location and Document Instance” Coming to this conclusion
One point seems clear. In using URLs to identify concepts (such as “http://x.org/love”), we need conventions for denoting each of these four things: name, concept, Web location and document instance.

Then there was also an article how the semantics of Topic Maps could help by Steve Pepper, titled “Curing the Web’s Identity Crisis”.
In his introduction Pepper writes:

In an important recent article on XML.com entitled “Identity Crisis” [Clark 2002], Kendall Clark addresses the issue of “identity” as it pertains to the World Wide Web. Clark quotes the
description of the Web by the W3C’s Technical Architecture Group (TAG) in Architecture of the World Wide Web [Jacobs 2002], as a “universe of resources”, where “resource” is to be understood according to the definition given in [RFC 2396] as being “anything that has identity”. Clark points out that the concept of “identity” itself is nowhere defined and moreover is severely problematic.

He cites the Article “Identity Crisis” by Kendall Grant Clark. In his introduction to the problem, Clark says:
The Identity of Resources.
In the APW’s view, the Web is a “universe of resources”. So far, so good. But what is a resource? The APW adopts the definition of resource from RFC
, a definition which has always made me uneasy, though probably because I’m still more inclined to think of these things like a philosopher than like a programmer or software system architect.

So, it is a philosophical problem. Ah. Now we come somewhere. Sadly, every time leobard tried to get a philosopher on this track, saying things like “I think that URIs will change the way we identify abstract concepts, a change that is fundamental to our constructivistic worldview”, philosophers answer: you young nerd, read 10 kilos of philosophical books and come back. Sure – but I won’t spend no time on that.

So – face it. The meaning of what a URI identifies os not defined. Hence, when TimBl announces he has a URI now and a Foaf file – what does this mean?

That we should identify the concept “Person named Tim Berners-Lee” using this uri?

perhaps, and perhaps thats the way it works: you explicitly say to identify the concepts you have in your mind using the URI you find most approapriate. When other humans copy your behaviour (and copy/paste your uri), URIs will identify concepts. Hm, perhaps.

So, next time when I shout “You are facing the Uri crisis”, don’t answer “I never heard there was a crisis” or “are we out of uris?” and think of a solution instead.

One Reply to “uri crisis – what do URIs identify?”

  1. actually, although i’m really thrilled by the vision of a semantic web and try to use pieces of it every now and then, i always stop working on them when i realize that RDF gives me the grammar, but lacks the words. it’s even more frustrating to see a semantic web community happily discussing the big picture and getting all excited about it, while there’s little me sitting there wondering wether, within this framework, one will ever be able to unambiguously identify anything.

    it seems someone’s building a house here and, while noticing that there’s something wrong, keeps telling us “I’ll decide about the bricks later, but look at those beautiful curtains! and wait until you’ve seen my china!”

    My personal feeling is that all went wrong when they expanded the (more or less) well defined URL into the concept of URIs. I can see the idea behind it, i know what it was supposed to be, but it simply doesn’t work i’m afraid. it’s too generic. and it would have been good to clearly separate the concept of a URL, a retrievable network location, from anything else.

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