[22 July 2008]
My colleague Thomas Roessler writes:
[The monotonic semantics of RDF] guarantee that you won’t run into a world of inconsistency when you discover additional information, and they also guarantee that you can learn things about the world piece by piece.
My evil twin Enrique responds: So let us start with the information that “The individual denoted by
http://www.w3.org/People/cmsmcq/2008/ns1#joe is identical to the individual named
http://www.w3.org/People/cmsmcq/2008/ns2#Josephus”, which I assume I can express using some predicate like the OWL
And now let us discover additional information in another triple store, which contains the information that “The individual denoted by
http://www.w3.org/People/cmsmcq/2008/ns1#joe is distinct from the individual named
http://www.w3.org/People/cmsmcq/2008/ns2#Josephus”, which it expresses using some predicate like the OWL
I’m having trouble understanding (concludes Enrique) how we can do this without either running into a world of inconsistency (a small world, perhaps, bounded in a nutshell, but still a world big enough for joe and Josephus to be both the same and different), or else running into a world in which we find that “inconsistency” has been defined to have a highly technical meaning under which the two triples just described are not actually inconsistent in the technical sense (why do I expect someone to start lecturing me about Herbrand models any moment now?), even though any application relying on the usual notions of identity and difference may find itself at a loss as to what to make of seeing them both in the same graph.
I reminded Enrique of the American pioneer Daniel Boone, who proudly claimed that he had never been lost in his life. Never? Never. [Pause.] “But I was a mite bewildered once for three days.” [Rimshot.]