W3C home > Mailing lists > Public > public-sw-meaning@w3.org > September 2003

Re: Proposed issue: What does using an URI require of me and my software?

From: pat hayes <phayes@ihmc.us>
Date: Fri, 26 Sep 2003 21:01:18 -0500
Message-Id: <p06001f31bb9a999d30e8@[]>
To: Tim Berners-Lee <timbl@w3.org>
Cc: public-sw-meaning@w3.org

>In-Reply-to Bijan's original
>, clarifications.

<big snip, mostly cuz I agree with it all>

>7 Naive protocols and safe operating procedures
>Actually, the whole question of damage raises another distinction.
>Most of the "intuition pump" example is about things going wrong.
>I think we may have to consciously distinguish in the design
>of the semantic web in general between the normal expected ways
>of going about things, which we can show will wok, and the
>operating procedures which will allow one to operate safely in
>a potentially hostile environment.

Agreed, important point.

>Example: a purchase choice system choses the cheapest product
>which is offered as being compatible with an hp:p314159.
>The naive protocol is for the seller to offer the compatibility and price
>system in the catalogue which you get by dereferencing the
>part URI, and the buyer loading the catalogs into its kb.
>A more secure system filters the catalogs for lies about
>which product is best.  You can define conformance with some
>market protocol in that the catalog only has data of a given form,
>but you still want to be careful about things which break it.
>Focussing, then, back on what an RDF document means, which
>was the original narrower scope than all of this, I would say we have
>to first define the naive protocol,
>- Use of an HTTP URI as a symbol in an RDF statement
>  refers to one thing which the URI owner intended.

Why? Why do we need to say that it refers to ONE thing? Even as a 
normal assumption. Surely, all we need here is the following:

>- The URI owner puts true, consistent, hum &/or machine
>readable information in the
>   document that you get should you chose to dereference the URI.

Right. Now, lets suppose that as well as there being a document that 
you get, that the document says that it refers to something.  (Eg the 
document at http://www.w3.org/2001/XMLSchema says "This document 
describes the XML schema namespace.") Under those conditions, then, 
accepting the truth of the document amounts to accepting that it 
refers to some unique thing. It might say that more formally in some 
way, or it might not say it at all.  But it seems to me that all we 
need to stipulate is that if it says something, then there is a 
ceterus paribus, normal, all things considered, good practice 
assumption being made by everyone involved that whatever it says, is 
being considered to be true. That seems the least we can reasonably 
say about this, and I think it is all we need to say about it; and it 
has the great merit of being susceptible to precise semantic 
description which applies both to SW stuff and NL stuff that you 
might find there, and it treats the URI according to existing Web 
architectural principles (you ping it, you get a representation, you 
assume its true) and it seems to conform with existing practice, 
insofar as there is one, and it cuts through useless debates. What 
exactly does http://www.w3.org/2001/XMLSchema denote? Well, use the 
Web, take a look, and see what it says.  If that doesn't tell you, 
nothing will.  We don't need to make this semantically dubious claim 
that URIs denote uniquely. There isn't even any way to make sense of 
that claim in many cases, and communication doesn't depend on it.


>- Nobody hijacks the domain name system, the LAN or the server,
>  or an intervening proxy, or the user's computer, etc
>If we could get that nailed down first, then afterwards we could launch into
>the questions of what happens when people lie, make mistakes,
>fix mistakes, the net goes down, and so on, as to whether we should
>make the best of it, model everything in an extra level of detail,
>take someone to court or call the to discuss it over lunch, et cetera.
>We can also define useful rules of friendly behavior which a community
>could adopt to make a working system within that community.

IHMC	(850)434 8903 or (650)494 3973   home
40 South Alcaniz St.	(850)202 4416   office
Pensacola			(850)202 4440   fax
FL 32501			(850)291 0667    cell
phayes@ihmc.us       http://www.ihmc.us/users/phayes
Received on Friday, 26 September 2003 22:05:34 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 19:56:01 UTC