What the meanging of "is" is

I think the right venue for resolving some of the philosophical questions of identity and URIs belongs in the IJCAI conference workshop and not on the TAG agenda.


Many TAG and other semantic web discussions about identity and reference ask questions about equality, identity, counting, and distinguishing "resources", for example, " Is the resource identified by URI X the same as the resource identified by URI Y?"
"How many resources does a URI identify?"

My perspective is that these questions are not well formed. Equality and countability are mathematical operations. The space of "resources" is not a set, has no well-defined notion of "identity", and there is no way, in general, of determining "equality".

 There is a notion of "inequality" but to the extent you can ask:

       "Is the resource identified by URI X the same as the resource identified by URI Y?"

generally you can determine "No" or "Maybe". In some circumstances, if X is string-equivalent to Y, the answer might be Yes.

Since you cannot, in general, determine equality of two resources identified by two different URIs, counting them or arguing "sameness" doesn't work.