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RDF Semantics - Identify vs. Denote distinction is not helpful

From: David Booth <david@dbooth.org>
Date: Tue, 01 Oct 2013 21:30:15 -0400
Message-ID: <524B7727.2080303@dbooth.org>
To: public-rdf-comments <public-rdf-comments@w3.org>
First off, I apologize for the lateness of these comments and how 
hastily they are written.  Given that people who are not members of the 
RDF working group cannot subscribe to the RDF mailing list -- even in 
read-only mode -- and there was no mention of it on the rdf-comments 
list (to which non-members can subscribe), and no mention of it in the 
editor's draft documents that i've been reading (in order to read the 
most up-to-date text), I did not realize that these documents were in 
Last Call.  Sorry!   I'll try to break my comments up into separately 
addressable issues.  Here is the first.

https://dvcs.w3.org/hg/rdf/raw-file/default/rdf-mt/index.html

In Section 4, The distinction between "identify" and "denote" does not 
seem helpful.  I think it adds more confusion than clarity.  AFAICT a 
key point of using the notion of interpretations is to allow IRIs to be 
mapped to entities in one's universe of discourse -- whatever real world 
entities one wishes to talk about.  By distinguishing between "identify" 
and "denote" in essence *two* mappings are being created: an 
identifies-mapping and a denotes-mapping.  This gives the impression 
that the identifies-mapping is the one that is used colloquially, but 
the denotes-mapping is the formal one addressed in the RDF Semantics. 
It seems to me that this dichotomy defeats the purpose of 
interpretations.  Interpretations are supposed to allow us to connect 
the formal semantics to the real world universe of discourse that we 
care about -- not to some universe of irrelevant, fictional entities 
that exist only in the idealized world of the RDF Semantics.

In reading this section, I also get the impression that the motivation 
for this distinction is to avoid quandaries cased by having an IRI that 
may ambiguously denote two different things.  Defining two different 
notions of mapping from IRIs to resources is the *wrong* solution to 
that problem.  There is no justification for preferentially choosing one 
of those mappings over the other.  They can both perfectly well be 
denotes-mappings, but under different *interpretations*.  (Remember: the 
same IRI can perfectly well map to *different* resources in different 
interpretations.)  This already works perfectly under the existing RDF 
Semantics.

In short, I think the definition of "identify" should be eliminated, as 
it adds confusion rather than helping.

David
Received on Wednesday, 2 October 2013 01:30:44 UTC

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