[Fwd: Re: A parable about RFC 3986.]

Okay, this is what I meant to send . . . 

On Wed, 2012-01-25 at 16:07 -0500, Jonathan A Rees wrote:
[ . . . ]
> The contradiction is that A both is and isn't a representation of P.
> Alice and Bob can't both be right if they say a statement and its
> negation respectively. (Should I spell this out? Alice says deref(U)
> has rep A but not has rep B, Bob says deref(V) has rep B but not rep
> A, they are both authoritative, so deref(U) not= deref(V),
> contradiction since P = deref(U) = deref(V).)

Thanks, that's a *little* more helpful, but there are still some crucial
pieces left out.  

If I'm understanding you correctly, Alice asserts (through her server)
that A is a representation of <U>, because dereferencing U yields A.
I'm not sure how she is asserting that deref(U) does *not* have rep B,
but maybe she wrote that assertion somewhere.  Similarly Bob has
asserted (through his server) that B is a representation of <V>.  And
somehow -- though you haven't said how, so I don't know if the "how" is
relevant -- Alice and Bob have also asserted that <U> and <V> are
owl:sameAs P (or some such).

So?  Alice and Bob have made contradictory assertions via their servers.
What's the big deal?  Nobody has to believe them.  And where, in this,
is there any relevance of the previously stated fact that P is a person?

To cut to the chase, it looks to me like the following is happening.  

1. Alice has effectively declared that U identifies a resource such that
<U> owl:sameAs <P> .  Alice has the authority to make this declaration,
because she is the URI owner of U.  

2. Alice has effectively also asserted something like
<U> :hasRepresentation A, by configuring her server appropriately.  As
the URI owner of U, she has the authority to do so.

3. Similarly, Bob has effectively declared that <V> owl:sameAs <P>, and
has configured his server to assert that <V> :hasRepresentation B.

4. We'll somehow take as a given that <P> cannot both have
representation A and B.

Taken together, these assertions are inconsistent.  But so what?
Nothing in semantic web architecture requires them to be consistent.

By fiat, Alice has the authority to declare that <U> owl:sameAs <P>.
But her authority to make that declaration does *not* make it
necessarily true.  It simply means that if <U> is used in a statement,
then <U> should be taken to have the meaning that Alice has declared it
to have.  And that meaning may perfectly well be vacuous if Alice has
supplied self-contradictory assertions in her declaration, or if the
assertions in her declaration conflict with other assertions that appear
in the context (read "RDF graph") in which <U> appears.  This is
completely independent of the nature of <P>.

[ . . . ]
> >> What distinguishes a fiat resource is that the
> >> representations of its states are *constitutive* of the resource -
> >> they are not subject to debate, reason, opinion, and so on, but are
> >> rather part of the resource's identity.

No, it isn't the resource that has a "fiat" quality.  It is the
*binding* between a URI and a resource that has a fiat quality: it is
established by fiat by the URI owner.  Or more accurately, the URI owner
establishes the binding of the URI to an ambiguously specified resource
via a resource *description* (effectively, a set of assertions).  The
binding of a URI to an (ambiguous) resource via its description is, in
the absence of community expropriation,
http://dbooth.org/2009/lifecycle/#expropriation 
by fiat: it is not subject to debate, reason, opinion, etc.  It defines
the resource's identity.  Again, this does *not* mean that the
assertions in the description are true.  


-- 
David Booth, Ph.D.
http://dbooth.org/

Opinions expressed herein are those of the author and do not necessarily
reflect those of his employer.

Received on Thursday, 26 January 2012 03:44:43 UTC