Social Meaning and RDF
This is a continuation of my comments on what I consider to be a fatal flaw in the RDF specification. I had submitted my views on this flaw to the W3C RDF Core Working Group before the beginning of the Last Call period in the message archived at http://lists.w3.org/Archives/Public/www-rdf-comments/2002OctDec/0297.html but the working group chose to go into last call without addressing my comments on this issue. What is the ``social meaning'' (Section 4.2 of RDF Concepts) of RDF? Does it have any relationship to how an RDF application should act? If so, what is this relationship and how can it be conveyed to an application? If not, what business does this have in a document about RDF? How does an RDF expression get to be asserted? What syntax can I use to assert RDF expressions, or to prevent their assertion? Can I use this notion in OWL? If not, then what good is it? Without any method given for asserting an RDF expression or graph, what good is a paragraph that starts ``When an RDF graph is asserted in the Web''? How is social meaning determined? Does it have to be part of the RDF model theory? Does it have to be part of an RDF graph? Does it have to be accessible on the Web? Must it be common knowledge, and for what community? Must it be written down somewhere? Can it exist only in someone's mind? The idea that RDF graphs contain ``defining information'' that is opaque to logical reasoners is ludicrous. An RDF graph is simply a set of RDF triples. It is certainly possible that there can be communities that have intended meanings for these RDF graphs, but these intended meanings are external to the RDF graph, and, indeed, external to RDF as a whole, and thus have no place in a normative part of a document about RDF. What social conventions surround the use of RDF? Even if there were some, why should they make their way into a normative section of an RDF document? The idea that some owner of a URI reference can control the use of that URI reference goes counter to the bedrock goal that RDF allows one to say anything about anything. The RDF model theory contains no hint that any of these sorts of restrictions are possible. The example in Section 4.5 of RDF Concepts brings forward these problems. The document at http://skunk.example.org/ does not entail anything derogatory about C:JohnSmith, which is reinforced in the section just above. This being the case, there is no reason for any notion related to RDF to bring this forward. If, however, the opposite was the case then there would be no way for any organization to deploy any RDF-based application. Such applications would not be able to understand the social meaning of the RDF they created or manipulated, and thus could easily create documents holding the organization liable for just about any imaginable consequence. In this case I would have no choice but to tell Lucent Technologies not to deploy any RDF applications.
Does the material on social meaning have any impact on the behaviour of an RDF application? If not, why is the material here at all?What are the mechanisms by means of which an RDF expression is designated as being asserted, as opposed to an expression which is not regarded as asserting some truth? Intended meanings are external to the RDF graph, not contained. As such, why are they covered in the normative aspects of RDF specification? The idea that some party controls the meaning of a given URI is counter to the goal that "anyone can say things about anything".
This comment seems to cover three main areas: