- From: Pat Hayes <phayes@ihmc.us>
- Date: Mon, 14 Jun 2004 13:57:42 -0500
- To: Jim Hendler <hendler@cs.umd.edu>
- Cc: "John Black" <JohnBlack@deltek.com>, "Sandro Hawke" <sandro@w3.org>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>, <public-sw-meaning@w3.org>
>A >>As a side note, I have a personal suspicion about the genesis of >>one of the ideas behind RDF. The sole evidence for it is that it >>explains (to me, at least) one of the more surprising notions that >>has been advanced about RDF, that the predicate carries the meaning. >>I suspect that after the web was created the creators looked at it >>and thought that it was good. An amazing amount of things can be >>done with just the simple relation of 'isRelatedTo'. Then they said, >>"But can't we do better than just to say this resource 'isLinkedTo' >>that resource? Couldn't we make the relation 'isLinkedTo' (or >>'isRelatedTo') carry more meaning. We should be able to say, >>'isLinkedToAsCreatorOf' or 'isLinkedToAsTheDateOf'. And instead >>of creating the link by embedding one URI in a document identified >>by another URI, lets give that more meaningful >>'isLinkedToAsCreateorOf' a URI name so that the meaning of the >>relation expressed can actually be looked up on the web as well." >>Sorry for the digression and for the error if I am mistaken. > > >I'm not sure why you say it this way -- one of the key features of >RDF is that you can have a labeled rather than an unlabeled graph, >and we RDFers say that lots of times. From the earliest days of the >web people argued that a set of labels would be useful - there was a >proposal (I think in an early MCF draft) to have about 10 particular >labels, and about the same time some of us started arguing for the >use of URIs giving us an infinite set of labels -- RDF realized this >was right, and it is a key part of the design. Thus, one way to >look at a basic RDF triple is simply "This URI is linked to that URI >by the relation in this third URI" -- and thus any individual or >group can create a relationship URI and use it -- and if they use it >consistently, the link can be useful. I think John's concern is not with this part of it, but that that there is another URI missing from the story, along the lines of: "This URI is linked to that URI by the relation in this third URI, says the owner of this URI" where that last URI identifies the .. what? Owner? asserter? commentator upon? .. of the ontology containing the triple which uses the first three URIs. I agree with John that this is heart of this issue. RDF itself (and OWL, of course) has a perfectly good propositional semantics but has no social semantics whatsoever, and doesn't even have any means for making an informal social meaning explicit. Am I asserting the ontology I publish, or merely exhibiting it, or holding it up to public ridicule, or what? How can I be clear about this? How can anyone else know what my intentions are? >However, another key idea grew about the same time -- as long as we >are using URIs, we could make those URIs dereferencable -- that is, >we could look and see if there is a document there, and if so, >perhaps that document could describe the link -- RDFS and OWL >provide vocabularies that live at those links and provide >information about the "intent" of those relationships. No, that is exactly what they do not provide. That is John's point: there is a gap here precisely because the SW notations only express CONTENT, they do not express INTENTION. The stuff about performatives in the paper I helped write was intended to be a step towards bridging this gap, since performatives in natural language are exactly where an intention is expressed unambiguously by stating - describing - the intention. If enough people say that Jack and Jill are married, in the right way and under the right circumstances, then they are married. If I say "I promise to buy you lunch" then an actual promise got created: I performed a social act by saying that I was performing it. Very handy, that is: it gets you from mere descriptions (which we indubitably have in RDF and OWL) to actual intentional actions: it gets assertings (denials, explicit non-assertings, endorsements, whatever) actually done, and in a publicly checkable way rather than being left implicit. > >And technically, that is the heart of the Semantic Web architecture >- links that can be named and described more formally. > >IMO, the social meaning issue arises from the fact that we have both >referencing and dereferecing going on. When links share a URI, and >there's no document at that URI to dereference, then it is clear >that any meaning of that term is in some sort of off-line "Social" >conventions between the users thereof. However, when we add the >dereferencing it becomes trickier -- because now we have to ask if >use of the term in some way "commits" to what is in the >dereferencing document, if the owner of that document controls the >use of the term, etc. > >There's lots of other "social meaning" issues on the Semantic Web, >and the threads on this list talk about many of them, but in my mind >the key ones are those that arise from the issue of the relation >between the named terms and the documents that describe, in some >formal way, the use of those terms Well, yes, but (IMO) only because such dereferencing is the only way to establish any kind of link between a URI and anything that can be plausibly attributed agency. In order for a promise (etc) to be done, there has to be an agent doing the promising. Similarly for asserting, denying, etc. . Without agents (and I really do mean SOCIAL agents, not software agents) in the picture, all we have is sentences being looked at: nothing is asserted at all. Pat > > >> >>And the absence of "...easy access to disagreements...", the >>ability to disagree with, deny, or refute propositions, as has been >>convincingly argued on this list, is of profound importance. >> >>[snip] >> >>> >(http://www.wiwiss.fu-berlin.de/suhl/bizer/SWTSGuide/carroll-ISWC2004.pdf) >>> > appears to me to fit right into what you want. >> >>I agree. The development of assertion described in this paper would >>be a great place to start. >> >>John Black >> >>> > > John Black >>> > Peter F. Patel-Schneider >> >>> -- sandro > >-- >Professor James Hendler >http://www.cs.umd.edu/users/hendler >Director, Semantic Web and Agent Technologies 301-405-2696 >Maryland Information and Network Dynamics Lab. 301-405-6707 (Fax) >Univ of Maryland, College Park, MD 20742 240-277-3388 (Cell) -- --------------------------------------------------------------------- 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 Monday, 14 June 2004 14:57:36 UTC