- From: Brian McBride <bwm@hplb.hpl.hp.com>
- Date: Sun, 18 Nov 2001 12:30:02 +0000
- To: Dan Brickley <danbri@w3.org>, <w3c-rdfcore-wg@w3.org>
At 11:51 16/11/2001 -0500, Dan Brickley wrote: [...] >Yes, though we need to go a little further than we have to date in >claiming that RDF content is meaningful. We then need W3C et al to provide >document formatting and protocol contexts (XHTML, SVG, mime, HTTP, >SOAP...) within which this meaningful content can be exposed. > > >RDF data *isn't* an arbitrary graph structure, and DanC is write to say >that we need the RDF spec to be clear on this. We claim that RDF data can >be _about_ things in the world. The Model Theory alone doesn't give us >that. RDF uses the URI specification as its primary means of anchoring >arbitrary >graphs to the physical and social world. The meaning of a piece of RDF >isn't fixed by the MT alone, but by the meanings that the URI spec >plus deployed Web practice gives to URI name strings. The meaning of RDF >content is furthermore fixed by the prose and rules associated with the >schemas/ontologies it draws upon. Where those definitions are murky, the >meaning of RDF instance data is murky. > >This is fine. We should say things to the effect that...: > > (i) RDF content has, on a good day, propositional content; it corresponds > to statements or propositions about entities in the real > social/legal world > >(ii) the Model Theory assumes such a correspondence, but does not itself > specify one. > >(iii) the correspondence between RDF content and propositions about the > world is fixed in part by facts about individual URI names (ie. what > they denote); in part by facts about the URI specification (rules > about how URI names can denote, (sometimes) fail to denote, etc.); > in part by the machine-readable rules associated with classes, > properties, and indivduals mentioned in the RDF content (or > indirectly through the schemas/ontologies used); and in part by > the natural language definitions specified in these schemas. > >(iv) the formal components of RDF (MT etc.) do not guarantee that any > piece of RDF instance data is meaningful, or that it corresponds to > propositional content. It may use incoherently > designed or inadequately defined classes and properties; or it may > use URI names whose referents are for some reason unclear or > indeterminate. > >(v) While the RDF design explicitly notes that RDF is intended to have >propositional content, despite these various obstacles, the core RDF specs >are agnostic regarding the various options for deploying this content in >the Web. In particular, RDF core does not enumerate the XML vocabularies >within which it may be embedded and retain its propositional nature >nor define mechanisms that distinguish the roles played by the XML >elements that may contain it in wellformed XML markup. RDF Core does not >claim that all XML document and data formats can be interpreted as having >propositional content, but notes for eg. that SVG's 'metadata' element and >(X)HTML's 'head' element are commonly understood in >this way. Similarly, the Core specs don't address protocols (HTTP) or >container formats (MIME), nor attempt to associate the propositional >content of RDF data with any particular real world entities such as >webmasters, document authors, editors, service providers. > >Plausible? Definitely. Can we take this as a starting point? Brian
Received on Sunday, 18 November 2001 08:29:55 UTC