Re: URIs quack like a duck

On Sun, 4 Jun 100, John Cowan wrote:
> Clark C. Evans scripsit:
> >  a) one de-references the function (if possible)
> >     and compares the resources directly.
> 
> As I have repeatedly shown on this list, resources
> *cannot* be compared directly, only the entity bodies that happen
> to represent them at a particular moment.

Let's not go there as the ground is too slippery.  *evil grin*

> >  b) an injective identification function is named.
> 
> What about direct assertions?  We can't in practice dereference the
> names "Hesperus" and "Phosphorus" to determine if they identify
> the same thing (because the planet Venus is not a network-retrievable
> resource), nor can we, in the Real World, limit ourselves to just
> one of these names.
> 
> But we can look in a database that informs us that Hesperus is Phosphorus,
> an *a posteriori* truth (it is neither trivial to claim it, nor absurd
> to doubt it).
> 
> So I add to your list:
> 
>    c) metadata informs us that the two URIs name the same resource.

I think that this is a higher level migration or 
re-writing layer (converting one document from 
namespace X into a document from namespace Y).  

That the current spec says *unique* but allows for
*non-unique* URIs is the core problem here, let us
solve it.  Putting this metadata system as a requirement
for an implementation of the namespace specificition
would be a step backwards.

For deterministic processes we need *unique* and 
*persistent*  names; it *is* what the spec says.

Yes?

Clark