On Sun, Jul 17, 2016 at 10:25 PM, Stathis Papaioannou <stath...@gmail.com> wrote:
> > > 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. > > I have only come across two theories of personal identity that are consistent and void issues inherent to body-continuity and psychological-continuity theories. The two consistent personal identity theories I am aware of are no-self (you are only a single thought moment and nothing else) and universalism (you are all thought moments and all people). Anything in between is bound to fall flat when you try to limit the scope of experiences you my ascribe that person to some biological or some psychological continuation when both of these continuations can changes over time. What are the practical limits to allowable change which preserve that person? It seems entirely arbitrary to me. All this said, whether you ascribe to no-self, universalism, biological continuity, psychological continuity or closest continuer theory, this is not of any relevance to Bruno's UDA. The thought experiment is a question of predictions made and the later confirmation or refutation of those predictions as remembered from the memories of duplicated entities. This does not require having any assumed theory of personal identity, it works even in the no-self theory of personal identity: Even if the Helsinki Man is an entirely different person from the Washington Man, the Washington Man can still confirm or refute the predictions of the Helsinki man he finds in his memory. Likewise if you looked at the experiment assuming universalism, where you believe "one mind" experiences the views of the Helsinki man the Washington Man and the Moscow Man, and you believe they are ultimately all the same person and all the experiences belong to all, this too, does not stop the Moscow Man nor the Washington Man from validating their predictions from their local points of view. Closest continuer theory I think is all a game with language to allow philosophers to try and duct tape over obvious problems with biological and psychological continuity theories, but it just introduces new problems of its own. Even if Moscow were closer to Helsinki and you said the Washington Man is not the Helsinki man, that again means nothing for the ability of the Washington Man to confirm or refute the predictions he finds in his memory (whether or not you say those memories are his or someone else's). Jason -- 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.
