Under this really boring title "The Semantics Are Important", Seth Ladd in his Semergence blog is making a really good point :
The identity is singular. The meaning is relative.
In other words, identity and identifiers can be shared, global, universal, whereas semantics/meaning, such as expressed in a particular RDF graph, is local, relative, context-bound, perspective-defined. And therefore multiple, orthogonal, non-compatible, globally inconsistent.
I like it more and more. This goes along the same lines as Pat Hayes' recent post, and puts again the question of how to deal with context. I'm not sure now, munching over Pat's arguments, that the context always needs to be explicited. I've been working those days on SKOS used to express simplified view of hierarchies (of any kind) in an OWL ontology. In some OWL ontology, one would find
a:SomeRegion a:partOf a:SomeCountry
In a simplified SKOS view
a:SomeRegion skos:broader a:Some Country
Reasoners and RDF stores are happy with the OWL version, search engines, taxonomy managers and the like are happy with the SKOS version. So one perspective by kind of tools/applications. What would not make sense would be to merge them, and entail that a:SomeRegion is at the same time an instance of a:Region and skos:Concept. It is not at the same time, it is one in some application context, and the other one in another context. No problem with that. So what is a:SomeRegion in essence, to use this arrogant word I saw passing in the previous post? Well, it's neti, neti, neither this, nor that. No big deal. Who cares?
Set this question about a week ago on the SKOS forum. An astounding silence has been the answer so far ...
[2013-08-01] : Still waiting for an answer ... more than 7 years after the issue is still open.