- From: pat hayes <phayes@ai.uwf.edu>
- Date: Wed, 20 Jun 2001 18:13:45 -0500
- To: Dan Connolly <connolly@w3.org>
- Cc: w3c-rdfcore-wg@w3.org
>Graham Klyne wrote: > > > > At 08:18 AM 6/15/01 -0500, Dan Connolly wrote: > > >Graham Klyne wrote: > > > > > > > > At 02:29 AM 6/15/01 -0500, Dan Connolly wrote: > > > > > > RDF absolutely has to make sense even outside the context of > > > > > > an enclosing document which can be given a uri. so ... > > > > > > > > > >So... what? That doesn't make any sense to me. > > > > > > > > > >An RDF document is an XML document. Each XML document > > > > >has a base URI (cf the infoset spec). > > > > > > > > If this is true, then it is not possible to transfer RDF >data in transient > > > > protocol elements. > > > > > >Why not? Transient things are resources too; you may or > > >may not specify what their URI is (in the case > > >of a mail messge, it would be mid:....); that doesn't mean > > >they don't have one. > > > > Well, by definition (as I understand these things) it's only a resource if > > it has a URI. > >I think you've slightly overstated the case there, >but the argument holds even the way you've phrased it, so... > > > The fact that something can have a URI (and anything can, right?) doesn't > > mean that it's got one. > >Suppose I say that it does. There's no argument to >refute me, is there? Well, I can refute you to my own satisfaction just by looking around my office at the books on the shelves. >i.e. there's no reason not >to adopt this as an axiom. Other than it is obviously and immediately false, no. However, that is usually a pretty good reason to not adopt an axiom. > > (Not every mail message has a Message-ID header, > > from which the mid: is derived.) > >Those messages can be named just like all the things >that aren't mail messages at all can be named. They CAN be named, but (1) naming is not giving a URI to, and (2) even if they could be named, most of them havn't been, as a matter of fact. And some things couldnt possibly be named, by the way. > > > From a practical viewpoint, having a URI but not knowing what it is > > doesn't seem to be significantly different from not having a URI. > >But this isn't an issue of practical viewpoints; it's >an argument of architectural constraints -- or rather, >lack of them. So the difference is significant. > >You trust that I have a birthday even though you don't >know it, right? By the same token, it seems easy >enough to accept that resources have URIs even though >those URIs aren't always specified. But I know that every human has a birthday. I would guess that you own a shirt, but Im not absolutely certain; and I have no idea if you own, say, a VW beetle. Whereas I *know* that some email messsages don't have a URI. > > > > > Which means that (say) the CC/PP spec, formulated *by design* >as a *format* > > > > only for client capability data, cannot be regarded as a valid RDF > > > application. > > > > > >I don't see how that follows. > > > > Because (by my lights) a CC/PP profile may be some data that doesn't have a > > URI. > >We disagree on that. > > > Which (by your lights) means that it cannot be valid XML hence not > > valid RDF. > > > > > > But what is the status of information that is not "on the Web"? > > > > > >Just think of everything as "on the Web". > > > > I don't. That sounds to me more like a religion, or act of faith, than a > > state of affairs. > >Well, that's how architecture and mathematics work, no? No. >i.e. by the same token, nothing compells you to agree that >2+2=4, nor that the DNS has a unique root. >But it follows from generally accepted axioms, >so you do agree, right? These are usually classified as necessary truths because they follow from mathematical principles, ie by definition. Nothing about the web follows from mathematics. > > > It's a matter > > >of perspective. There aren't any constraints in the > > >design of the Web that allow you to deduce a contradiction > > >from saying "every document is on the Web". > > > > More important, I think, than the lack of a contradiction is a sense of > > common understanding (which, also, is an act of faith...). > >Alas, it's true that a lot of folks think of the Web >as HTTP+HTML. They speak of "the Web or email or ftp" >when they should say "HTTP or email or ftp, all of which >are part of the Web." The telephone system is also >part of The Web, as is IRC etc. The web uses the phone system, but it does not include it. I do actually speak on the phone from time to time. >cf rough notes > http://www.w3.org/2001/01/rtriw44 >and running code > http://dev.w3.org/cvsweb/2001/telagent/ > >I agree that this common understanding is somewhat lacking >and important to achieve; I plan to spend considerable >effort developing it over the next few years. >But meanwhile, the 10 year history of the Web >is evidence that this axiom is useful; can we agree that >for the purposes of the RDF spec, every document is in the Web? No, we cannot. I refuse to accept as an axiom something that I know to be false and, moreover, I know to be false because I can make it false in a few seconds by writing something with a pen on a piece of paper. Pat Hayes --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola, FL 32501 (850)202 4440 fax phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Wednesday, 20 June 2001 19:13:47 UTC