Ceci n'est pas une pipe

Sean McGrath on reality distortion:

Interesting (if mindbending) thread going on over at the W3C in the www-tag group. In this response to a message from Roy Fielding, Tim Berners Lee asserts that a URI identifies a web page - not just a representation of a resource at time t which may or may not be a web page (my understanding of the REST position on Web architecture). I was glad to see Tim Bray responding and consequently, I've cancelled my appointment to have my brain declared a reality distortion field. [ Sean McGrath, CTO, Propylon]

Are you shocked to see that the architects of the Web are still, ten years on, quite unable to agree on questions like "What does a URI identify?" Don't be. This is a testament to the power of naming in general, and to the specific naming system called the Web whose power we have only begun to understand and apply.

In the www-tag thread Sean mentions, Tim Berners-Lee points to his document What do HTTP-URIs identify? which ends with a set of exercises. One references Magritte's \"Ceci n'est pas une pipe" puzzle. Here's another:

1) What does " http://www.amazon.com/exec/obidos/ASIN/ 0679600108/qid=1027958807/ sr=2-3/ref=sr_2_3/103-4363499-9407855" identify?
  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 I realized that part of that URI, namely 0679600108, can be used to form other URIs -- notably, ones that perform lookups in library OPAC systems -- a whole bunch of librarians saw they could empower their users to connect to libraries in a new way. Tim Bray's Antarctica system aims to similarly empower users. "We try really hard to pack as much of the map identification into the URI as possible," he says. Do those URIs identify the map or the territory? We can never fully resolve such questions. Nor must we in order to build information systems that make sense to people.

Former URL: http://weblog.infoworld.com/udell/2003/01/27.html#a582