- From: Dan Brickley <danbri@w3.org>
- Date: Fri, 31 Aug 2001 15:00:53 -0400 (EDT)
- To: pat hayes <phayes@ai.uwf.edu>
- cc: <www-rdf-logic@w3.org>
(happily removing QNames from Subject: line) On Fri, 31 Aug 2001, pat hayes wrote: > >On Thu, 30 Aug 2001, pat hayes wrote: > > > > > [...] Really pinning down actual *reference* to *real things* is a > > > very, very tricky business, one that is way beyond the ability of > > > current semantic theories to analyse, and therefore probably best > > > left aside for now in these discussions. > > > >Amen! This is however something that Semantic Web (via our use of both > >URIs and of RDF descriptions for identification) will need to > >engage with at some point. > > I agree, but be ready for having to do some hard, basic (and > therefore slow) research. New syntaxes are easy, and model theories > can be churned out to fit most any reasonable intuitions about > consistency, but reference is harder. Yes... reference is far murkier, theoretically. And imho likely to stay that way. The precision that we achieve through DAML+OIL-style formalism will always be in tension with the unavoidably fuzzier aspects of meaning associated with our notion(s) of reference. (which is fine; interesting even...) > > I do think that the 'reference' aspect to > > 'meaning' is something we'll need to deal with if SW is to fulfill > > expectations w.r.t. ecommerce etc. > > Ecommerce only requires something that works pragmatically. Sure; I don't mean to suggest that the SW will be paralysed because nobody has perfected a formalisation of how URIs denote. People will find way to build systems that buy and sell (and lie and cheat) regardless. > I'm sure there are several ways to make the SW work well enough for ecommerce, > but if the $$ have to wait for a universal theory of reference, the > investors had better be ready to take a very long view. Wiser to give up on trying; everything I've read on theory of reference inclines me to think that the only way to succeed is to give up. Stephen Stich writes (imho) quite persuasively on this... (not quite the excerpt I was looking for, but all that Google could find...) http://www.nyu.edu/gsas/dept/philo/courses/consciousness97/papers/stich.html [[ ... Before I could start on that project, however, there was a prior question to be confronted. If the goal was to produce a correct theory of reference, I would have to get clear on what it is that makes a theory of reference correct or incorrect. What exactly are the facts that a correct theory of reference is supposed to capture? And how can we find out whether a theory has succeeded in capturing those facts? [...] That argument starts with a hunch, albeit a widely shared one. While there are lots of theories of reference on the market these days, my hunch is that the accounts that do the best job at capturing people's relatively firm and stable intuitions about reference are not those that follow the path staked out by Ramsey and Lewis, but rather those that tell what Lycan calls a "causal-historical" story. The basic idea of these theories, as we saw earlier, is that words get linked to things in the world via causal-historical chains. The first step in creating such a chain is a "grounding" or a "reference fixing" - an event or process (or, more commonly, an array of such events or processes) in which a term is introduced into a language to designate an object or a kind of objects. Following this there is a series (often a very long series) of reference preserving transmissions, in which the term is passed from one user to another, preserving the reference that was fixed when the term was introduced. But, of course, not just any way of introducing a term into a language will count as grounding the term on a particular object or kind of objects, and not just any way of passing a term from one user to another will count as a reference preserving transmission. The legitimate groundings and transmissions will be those embedded in causal-historical chains that are sanctioned by intuition. When one looks carefully at the class of groundings and the class of transmissions that pass this test, however, it appears that in each class the allowable events are a mixed bag having at best a loosely knit fabric of family resemblances to tie them together. ]] While I could imagine someone setting out to redescribe URIs in terms of an initial 'GroundingEvent' or 'NamingEvent', and (say) a causal-historical account of naming, I wouldn't join a W3C Working Group attempting such a thing if you paid me! Meanwhile, as you say, ecommerce will surely happen regardless. So I'm not spreading doom and gloom; just claiming that reference is the weak spot when we come to formalise the 'semantic' web. --danbri
Received on Friday, 31 August 2001 15:00:54 UTC