| To: | "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx> |
|---|---|
| From: | Christopher Menzel <cmenzel@xxxxxxxx> |
| Date: | 2008年1月16日 19:13:04 -0600 |
| Message-id: | <09FEB5AF-4902-4BB0-B954-4B4FB9D32D30@xxxxxxxx> |
At 11:11 AM -0600 1/14/08, Chris Menzel wrote:On 2008年1月13日, Pat Hayes wrote:At 3:28 PM -0600 1/13/08, Christopher Menzel wrote:On Jan 13, 2008, at 1:15 PM, Pat Hayes wrote:
... McCarthy claims that and-distribution applies to both:(ist c (p & q)) iff ( (ist c p) & (ist c q) )but there are certainly some cases of time-context where this fails, eg there was one day last year when I was (at various times) in five states, but I have never been in five states all at once. So apparently(ist thatDay (Pat in Mississippi)) & (ist thatDay (Pat in Kentucky))but not
引用][(ist thatDay ((Pat in Mississippi) & (Pat in Kentucky)))Not so clear to me that this is a counterexample to and-distribution. Seems to me that one _could_ do the semantics of ist vis-a-vis temporal contexts so that something that is true with respect to a given interval t has to be true with respect to all subintervals of t.
Yes, you can. And McCarthy uses that semantics, and so concludes (and takes it as axiomatic) that ist distributes over conjunction. But examples from natural language seem to often obviously have the dual interpretation, as here. So for example there is a famous Italian movie, "Last year in Marienbad", all about something that happened in Marienbad the previous year. But it didn't happen everywhere in Marienbad, for the entire year. Examples of this kind of 'contextualization' are rampant in natural language: so what supports the claim that the dual form must be correct, so correct indeed that it is a logical truth?
[
Well (not that you of all people don't know this), ">引用]nd-distribution.Exactly: that was my entire point.
And yet, as I think you know, advocates of context logic (in particular, of McCarthy's) have insisted thatanycoherent or rational notion of truth in a contextmustsatisfy this axiom, which of course is why it is adopted as an axiom.
Slightly weaker: (not (ist t (P & (not P)))). I think any notion which fails this has no coherent logic. But we may well disagree here:[I don't think that is a viable principle for at least some notions of contextsI presume you are thinking of states of belief and other 'psychological' context-ish things.
[You'll have to forgive me if it appeared otherwise, but I was quite certain I wasn't saying anything you were unaware of, Pat. However, it struck me that your claim that ">引用]xplained.No, my point was that there exists a perfectly reasonable semantics for 'ist' which made it invalid.Well, we couldn't be in more violent agreement. :-)I guess I don't see much difference between between saying there are different theories of context and different logics of context. "Logic" is really just an honorific title we bestow on a formalization of a cluster of concepts whose applicability is particularly broad and hence whose meanings we've attempt to fix, semantically or proof theoretically. That said, in the context of knowledge sharing and the semantic web where it would be good to stick to a single (though flexible) classical logical framework, theories seem like the way to go from a practical point of view.So let a hundred flowers bloom -- be they logics or theories. :-)-chris
_________________________________________________________________ Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/ Subscribe/Config: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/ Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx Shared Files: http://ontolog.cim3.net/file/ Community Wiki: http://ontolog.cim3.net/wiki/ To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx (01)