On Oct 7, 2009, at 3:23 PM, Matthew West wrote: (01)
> Dear John,
>
>>
>> MW> ... if I want to talk about 2 eyed sheep and 4 legged sheep
>>> and determine if they are necessarily the same, then I need
>>> only use sets that that go across all possible worlds.
>>
>> But those sets are purely imaginary.
>
> MW: Lewis would disagree with you. He claims that they are real and
> not
> imaginary, hence modal realism. This is really a feature of 4
> dimensionalism though. In 3D only the present exists, and neither the
> future or past do, whereas with 4D both the past and the future
> exist as
> well as the present. I am therefore not surprised that he chooses to
> claim the possible worlds exist too. On the other hand I am
> indifferent,
> since it seems to me to make no difference. (02)
A point that might be relevant is that the 4D approach gives a natural
account of what a possible world is. Lewis had to simply propose that
they existed, a stance that was never widely popular, to put it
mildly. But if we accept that 4D histories - spatiotemporal envelopes
of events and physical existence - are real, and if, as seems very
natural, we assume that they can stand in a relationship of
containment to one another, ie have a mereology, and if we make a few
very natural assumptions about this relationship, then one can show
mathematically that there must be maximal elements in the space of 4D
histories (maximal ideals in the order structure), and these play
exactly the required role of possible worlds. So a possible world is
simply a largest chunk of 4D space. Which is a very nice picture,
seems to me. (03)
Matthew, do you know if this has been developed by anyone and written
up? I had meant to write it years ago, but never got around to it. If
I havnt been gazumped yet, I might put it on the list of things to
write when I retire. (04)
> What does make a difference is that the membership of these sets is
> unknowable - we do not have access to other possible worlds.
>
>> Your operations are
>> logical manipulations based on the axioms and descriptions
>> of those possible worlds. You are doing the same kind of
>> reasoning that Montague and others call 'intensional'.
>
> MW: Yes of course. When did I ever say otherwise?
>>
>> MW> I can see that these sets are...
>>
>> The word 'see' in that sentence is metaphor.
>
> MW: Of course. I thought you liked metaphor and analogy.
>
>> Nobody can
>> actually observe an imaginary world or anything in it.
>
> MW: That is not enough to make it imaginary. I can't see the past
> either.
>
> Regards
>
> Matthew West
> Information Junction
> Tel: +44 560 302 3685
> Mobile: +44 750 3385279
> matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
> http://www.informationjunction.co.uk/
> http://www.matthew-west.org.uk/
>
> This email originates from Information Junction Ltd. Registered in
> England and Wales No. 6632177.
> Registered office: 2 Brookside, Meadow Way, Letchworth Garden City,
> Hertfordshire, SG6 3JE.
>
>
>
> _________________________________________________________________
> Message Archives: http://ontolog.cim3.net/forum/uom-ontology-std/
> Subscribe: mailto:uom-ontology-std-join@xxxxxxxxxxxxxxxx
> Config/Unsubscribe: http://ontolog.cim3.net/mailman/listinfo/uom-ontology-std/
> Shared Files: http://ontolog.cim3.net/file/work/UoM/
> Wiki: http://ontolog.cim3.net/cgi-bin/wiki.pl?UoM_Ontology_Standard
>
> (05)
------------------------------------------------------------
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 (06)
_________________________________________________________________
Message Archives: http://ontolog.cim3.net/forum/uom-ontology-std/
Subscribe: mailto:uom-ontology-std-join@xxxxxxxxxxxxxxxx
Config/Unsubscribe: http://ontolog.cim3.net/mailman/listinfo/uom-ontology-std/
Shared Files: http://ontolog.cim3.net/file/work/UoM/
Wiki: http://ontolog.cim3.net/cgi-bin/wiki.pl?UoM_Ontology_Standard (07)
|