On 18 July 2016 at 12:35, Bruce Kellett <bhkell...@optusnet.com.au> wrote:
> On 18/07/2016 12:10 pm, Stathis Papaioannou wrote: > > On 18 July 2016 at 11:54, Bruce Kellett <bhkell...@optusnet.com.au> > wrote: > > I have said several times that probability is a problem for the Everettian >> or MWI view. This is not a problem of defining a measure over a possible >> infinite number of worlds -- though that is certainly a problem that has >> not really been solved -- but the main difficulty lies in the observation >> that probability makes little sense in a situation in which everything >> possible does happen. So there is no workable notion of probability in the >> Everettian multiverse. >> >> Standard quantum mechanics gets around this in a fairly straightforward >> way: the "other worlds" in which alternative outcomes occur are disjoint, >> with no possible future interaction with the world in which we find >> ourselves. Such alternative outcomes can thus be safely ignored because >> they can have no possible effect on the observer or on his future >> evolution. Decoherence ,and the irreversibility of completed experimental >> outcomes, thus reduce QM to an effective collapse situation -- there is no >> physical collapse, but FAPP the other worlds have vanished from existence. >> > > You seem to be saying that if the copies in the other worlds effectively > vanish due inaccessibility, this is fundamentally different with regard to > personal identity compared to the case of duplication within the one world. > I don't see why that should be so. It may solve some practical problems, > such as which copy gets the possessions of the original, but these are not > fundamental problems with personal identity. > > > Practical problems are what is at stake in personal identity, and the > inaccessibility of other worlds solves these because we only look for a > closest continuer in the world we actually inhabit -- all others are > irrelevant for any purposes whatsoever. A theory of personal identity has > to solve practical problems, and to accord with our expectations and > intuitions in difficult cases. That is why person duplication scenarios are > a problem for a satisfactory theory. > Practical problems are very important but they do not necessarily impact on personal identity. If God grants me a vision of my copies in other worlds that would be interesting, but it would not make me change my view of personal identity in general or my identity in particular given that I already believed those copies were out there anyway. "Closest continuer theory" should not be presented as if it is the standard philosophical position on personal identity, let alone the only correct one. It has serious inherent problems, eg. it implies that if two identical copies of you are made in a duplication experiment then there is no closest continuer and you have not survived. -- Stathis Papaioannou -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
