On 9 September 2015 at 09:23, Bruce Kellett <[email protected]> wrote:
> On 9/09/2015 8:56 am, Stathis Papaioannou wrote: > > On 8 September 2015 at 22:11, Bruce Kellett <[email protected]> > wrote: > >> On 8/09/2015 9:14 pm, Stathis Papaioannou wrote: >> >> On 8 September 2015 at 20:48, Bruce Kellett < <[email protected]> >> [email protected]> wrote: >> >>> On 8/09/2015 8:40 pm, Stathis Papaioannou wrote: >>> >>> >>> On 8 September 2015 at 17:39, Bruce Kellett < >>> <[email protected]>[email protected]> wrote: >>> >>>> On 8/09/2015 4:56 pm, Stathis Papaioannou wrote: >>>> >>>> I will ask you the same question as I did Brent: do you conclude from >>>> the fact that when you toss a coin it comes up either as head or tails that >>>> the world does not split into two parallel versions of you, one of which >>>> sees heads and the other tails? >>>> >>>> I would conclude that a coin toss does not provide any evidence for >>>> multiple worlds or a split. The only evidence we have from this data is >>>> that the outcome of the toss is uncertain. There is no evidence there for >>>> any split of anything. >>>> >>> >>> It is not evidence FOR a split but is it evidence AGAINST a split? >>> >>> >>> It is evidence that the assumption of a split is not necessary in order >>> to understand everyday happenings. So, by the application of Occam's Razor, >>> no split happens. >>> >> >> So you agree that we would still observe the probabilities we do if we >> lived in a deterministic world in whaich all possibilities are realised? >> >> No, because not all possibilities happen in this world. If all >> possibilities were realized in this world, then there would be no >> uncertainty, no probabilities. Possibility and actuality would be the same >> thing. All the horses would win the Melbourne cup; and we don't live in >> such a world. >> > > Obviously, not all possibilities happen in this world, but they might > happen in parallel worlds that don't interact with each other. The argument > is that probabilities emerge from this, since you don't know which world > you will find yourself in. You bet on the favourite in the race because you > think you are more likely to end up in a world in which the favourite wins. > > In other words, probabilities can make perfect sense in a single > deterministic world. This was understood a long time ago with the > development of statistical mechanics. The idea that "all possibilities > happen in parallel worlds" does not actually make a lot of sense. There is > no current physical theory that implies this (without the addition of a lot > of unevidenced assumptions). So probabilities do not emerge from this, they > come from quite simple assumptions of randomness and ignorance. > > Probability in the MWI of quantum mechanics is problematic. Regardless of > claims to be able to derive the Born Rule in Everettian models, all > attempts fail because they are circular -- they need the Born rule in order > to have non-interacting worlds, so you cannot then use these independent > worlds to derive the Born rule. Gleason's theorem is no help -- it suffers > from all the same problems as the Deutsch-Wallace approach. > You don't seem to be disputing that we would still experience a probabilistic world even if all possibilities were actually realised, even though you do dispute that we in fact live in such a world. I'm not sure if you are disputing that, to give a simple model case, if a coin was tossed and the world split in two, with one version of you seeing heads and the other tails, the probability of each outcome is 1/2. -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
