- From: Pat Hayes <phayes@ihmc.us>
- Date: Thu, 8 Jul 2010 12:16:06 -0500
- To: Toby Inkster <tai@g5n.co.uk>
- Cc: Dan Brickley <danbri@danbri.org>, Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
- Message-Id: <855DB070-B5B9-4BC6-AC83-F29F5C2F440A@ihmc.us>
On Jul 7, 2010, at 6:57 AM, Toby Inkster wrote: > On Tue, 6 Jul 2010 16:11:19 -0500 > Pat Hayes <phayes@ihmc.us> wrote: > >> The world doesn't have facts like that in it. Classes and properties >> are intellectual constructs, not the stuff of reality. Hell, if a >> particle can be a wave, then surely a class can be a property. >> Anyway, RDF doesn't make logical a priori rulings about these kind >> of metaphysical segregations. For example, xsd:Number is a class, a >> property and an individual in RDF. > > Indeed - but who has claimed that classes and properties are disjoint? > Although they may well overlap in some cases, foaf:Person still > isn't a > property. > > Without knowing the definition of foaf:Person, it's difficult to > conclude that foaf:Person is not a property. However, even without > knowing the definition of a literal, it is easy to conclude that it is > not a suitable node to be used as a property Well, thats what I thought too, until people started using them that way in CLIF/IKL. It is very dangerous to presume that one can see clearly, ahead of time, that a construct cannot be usefully be used by anybody else. And such triples do have a meaning, technically, since the RDF semantics gives them one, without indeed any modification *at all*. > , so in my opinion, it is > sensible to state that triples containing a literal as the predicate > have no meaning (even though I think they should be syntactically > allowed). I would veto this option. To do this would be a lot more work than not doing it; and it would greatly complicate the semantic specification, which would have to keep track of this 'meaninglessness'. One could have a situation, for example, in which A entails B entails C, A and C are perfectly fine, but B has been declared 'meaningless'. Should this inference be blocked? Should it be an error? Why are we even asking this question? Pat > > -- > Toby A Inkster > <mailto:mail@tobyinkster.co.uk> > <http://tobyinkster.co.uk> > > ------------------------------------------------------------ IHMC (850)434 8903 or (650)494 3973 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Thursday, 8 July 2010 17:17:30 UTC