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## Re: [ontolog-forum] 3D+1 (was presentism...was blah blah blah)

 To: "[ontolog-forum]" Yu Lin Thu, 3 Feb 2011 11:58:55 -0500
 I agree with 4D approach. (It's even interesting that people is mentioning GOD here.)    (01) However, the question is: what kind of entity time is? a 4D entity? Or something else?    (02) Regards, Asiyah    (03) On Thu, Feb 3, 2011 at 11:35 AM, Wacek Kusnierczyk wrote: > On 2/3/11 3:37 AM, Pat Hayes wrote: >> Ian, here's a non-philosophical way to characterize it. Start with an atomic >sentence of the form R(a, b), with no time involved, and suppose that a and b >here are ordinary uncontroversial physical objects, say. Intuitively, they are >3D things. Now add time, t. Where do we put the time parameter? Several >answers can be given. >> >> 1. Attach it to the sentence, meaning that the sentence R(a,b) is true at >the time t.  This gives you a hybrid or context logic where the times are >possible temporal worlds/indices or contexts, to which truth is relativized. >But the sentences being so relativized do not themselves make any reference to >time. Call this 3D. >> >> 2. Attach it to the relation as an extra argument, and call the relation a >'fluent': R(a, b, t) This gives you the classical AI/KR approach which used to >be called the situation calculus, where one quantifies over times in the KR >language itself, but the object terms are still thought of as denoting 3D >rather than 4D entities. Call this 3D+1. >> >> 3. Attach it to the object terms (using a suitable function, written here as >an infix @): R(a@t, b@t) This requires us to make sense of this @ operation, >and it seems natural to say that it means the t-slice of the thing named, >which now has to be re-thought as a 4D entity. So the a, b things have morphed >form being 3D (but lasting through time) to being genuinely 4D, and having >temporal slices or parts. Call this 4D. >> >> For some folk this last step is apparently mind-boggling, although to me it >is puzzling how one can think of something being 3D and also extended in time >and have it *not* be 4D. For yet other people (think OBO), there are >apparently two kinds of thing in the world, one kind (continuants) which must >be described using the 3D+1 style , the other (occurrents) which should be >described using the 4D style. God alone knows why anyone would believe that >there are two ways to exist in time, but there's nowt as queer as folk, as >someone's grandmother used to say. >> >> What I like about this way of contrasting the options is that it makes it be >simply a matter of syntax - where in the sentence to attach the temporal >parameter - and not one of metaphysics. Syntax is way easier than metaphysics. >It also means that one can see quite clearly how to make the various formal >techniques work together, by allowing the temporal parameter to 'float'. In >fact, with a bit of extra work one can embed almost all the necessary temporal >reasoning into a generalized unification algorithm which extracts temporal >constraints during the unification process. I have all the details somewhere >if you (or anyone else) are interested. >> > > By way of a naive, as usual, question, I wonder if the above could not > be syntactically summarized as > > 1. R(a,b)@t > 2. R@t(a,b) > 3. R(a@t,b@t) > > vQ > > _________________________________________________________________ > Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/ > Config Subscr: 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 join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J > To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx > >    (04) _________________________________________________________________ Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/ Config Subscr: 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 join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx    (05)
 Current Thread Re: [ontolog-forum] 3D+1 (was presentism...was blah blah blah), (continued) Re: [ontolog-forum] 3D+1 (was presentism...was blah blah blah), Yu Lin <= Re: [ontolog-forum] 3D+1 (was presentism...was blah blah blah), doug foxvog Re: [ontolog-forum] 3D+1 (was presentism...was blah blah blah), John F. Sowa Re: [ontolog-forum] 3D+1 (was presentism...was blah blah blah), Chris Partridge Re: [ontolog-forum] 3D+1 (was presentism...was blah blah blah), John F. Sowa Re: [ontolog-forum] 3D+1, doug foxvog Re: [ontolog-forum] 3D+1, John F. Sowa Re: [ontolog-forum] 3D+1 (was presentism...was blah blah blah), Rich Cooper