- From: Pat Hayes <phayes@ihmc.us>
- Date: Thu, 20 Sep 2007 12:19:33 -0500
- To: Dan Connolly <connolly@w3.org>
- Cc: Tim Berners-Lee <timbl@w3.org>, Technical Architecture Group WG <www-tag@w3.org>, Susie Stephens <susie.stephens@gmail.com>
>Pat Hayes wrote: >> >>> >>>7. "On the Semantic Web, URIs identify not just Web documents, but >>>also real-world objects like people and cars, and even abstract >>>ideas and non-existing things like a mythical unicorn. We call all >>>these things resources." >>> >>>Of course many people would consider the Traditional Web to >>>include mailto: links. Suggest: >>> >>>"On the Semantic Web, http: URIs identify not just Web documents, >>>but also real-world objects like people and cars, and even >>>abstract ideas and non-existing things like a mythical unicorn. We >>>call all these things resources." >> >>This seems to me to embody the central error which is causing so >>much trouble. In what sense can a URI (or indeed any name: the fact >>that is a URI is irrelevant in this case) be said to "identify" a >>real-world or nonexistent entity? The direct answer is, it CANT. To >>even use this word "identify" in this sense and in this kind of a >>case, is clearly and provably WRONG. > >It seems pretty clear that the name "Dan Connolly" identifies >me and that I am a real-world entity. You are real, I grant you. And "Dan Connolly" is your name. But does that name "identify" you? Seems to me that in order to justify this usage, it would have to be that if someone who didn't know you or anything about you were given just that name, "Dan Connolly", a string of 12 characters, that they could figure out from that string which real-world entity you actually are. Maybe not *locate* you, but at least single you out from all the the other DCs there might be. But in fact they couldn't, because there are others with the same name, who therefore it also 'identifies' if it identifies you. (Eg http://www.hospitalitynet.org/news/4012693.search?query=+%22dan+connolly%22) Is that enough of a proof? Maybe this criterion is set too high, although I kind of transcribed it from the Web requirements for the "identifies" relationship between URIs and 'information resources'. But if this is too high, why do you and the TAG insist on saying "<name> identifies <thing>" instead of the more usual and completely non-puzzling "<name> is a name of <thing>" or even "<name> refers to <thing>" ? Isn't this 'identifies' usage supposed to suggest SOME kind of similarity between the URI-to-information-resource relationship and the URI-to-Dan Connolly relationship? We usually say "identifies" rather than merely "is a name of" when the identifier can be USED to single out the thing named from the universal multitude, just as an xxtp: URI can be USED to actually GET something. But names can't be used like this, in general: they are just names. They aren't anything like addresses or identifiers, because they don't identify. They just name. >If you have a proof that this is not so, I'm quite curious to see it. The proof I had in mind was the fact that just about any large first-order theory has nonstandard models, which follows from Goedel's theorem, for arithmetic, but informally (OK, its not a PROOF any more) is clearly true for almost any reasonably expressive theory with infinite models. Under these circumstances, no amount of ontological content or description is going to be enough to single out one sense of "Dan Connolly" from some others; and there will always be others. So apart from the above objection, and even if one buys into the fantasy of URIs being a globally unique naming system, there will still be SW issues that one ontology thinks of persons like you in one way and another ontology thinks of them in a different way. Im not sure how you like to describe this inevitable situation, but one way that makes semantic sense is to say that there are in fact two (and more) distinct entities, sorry resources, which are both 'you'. And its no defense to say that you FEEL like one thing. Of course we all feel like that: it only follows that this is what it feels like to be a whole lot of person-things at the same time. Pat > >-- >Dan Connolly, W3C http://www.w3.org/People/Connolly/ -- --------------------------------------------------------------------- IHMC (850)434 8903 or (650)494 3973 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 cell phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Thursday, 20 September 2007 17:19:44 UTC