On Sunday, October 6, 2019 at 3:25:41 AM UTC-5, Bruno Marchal wrote: > > > > On 6 Oct 2019, at 02:50, Russell Standish <[email protected] > <javascript:>> wrote: > > > > On Sat, Oct 05, 2019 at 09:05:49PM +1000, Bruce Kellett wrote: > >> On Sat, Oct 5, 2019 at 7:15 PM Bruno Marchal <[email protected] > <javascript:>> wrote: > >> > >> On 5 Oct 2019, at 07:14, Bruce Kellett <[email protected] > <javascript:>> wrote: > >> > >> > >> On Sat, Oct 5, 2019 at 1:10 AM Bruno Marchal <[email protected] > <javascript:>> wrote: > >> > >> According to the above non-separable wave function, that means > that Bob > >> gets only the ket |->, > >> > >> > >> That is vague. It means that Alice will access to the Bobs who get > that > >> state, and never access to the Bobs who did not got it. > >> > >> > >> Exactly. And this is what you are required to explain. Just stating it > as a > >> fact is not an explanation. > > > > ISTM that this follows from the Born rule - the probability of both > > Alice and Bob seeing the same spin is strictly zero. > > > > I understand that there are problems in deriving the Born rule from > > the MWI, and that derivations that purport to do so (such as mine) are > > contentious (to put it politely :)). So it doesn't exactly solve the > > problem, but maybe directs us toward where the solution lies. > > > > What I do get is Bruno's point that a single world assumption turns a > > nonlocal state into FTL "influence", the mechanism of which is quite > > unimaginable as you point out. An argument by incredulity, as it were, > > for the MWI. > > Exactly. > > Bruno > >
Going back to what Carroll precisely specifies: https://www.preposterousuniverse.com/blog/2015/02/19/the-wrong-objections-to-the-many-worlds-interpretation-of-quantum-mechanics/ Now, MWI certainly does *predict* the existence of a huge number of unobservable worlds. But it doesn’t *postulate* them.* It derives them,* from what it does postulate. And the actual postulates of the theory are quite simple indeed: 1. The world is described by a quantum state, which is an element of a kind of vector space known as Hilbert space. 2. 3. The quantum state evolves through time in accordance with the Schrödinger equation, with some particular Hamiltonian. That is, as they say, it. Notice you don’t see anything about worlds in there. The worlds are there whether you like it or not, sitting in Hilbert space, waiting to see whether they become actualized in the course of the evolution. Notice, also, that these postulates are eminently testable — indeed, even falsifiable! And once you make them (and you accept an appropriate “past hypothesis,” just as in statistical mechanics, and are considering a sufficiently richly-interacting system), the worlds happen automatically <http://www.preposterousuniverse.com/blog/2014/06/30/why-the-many-worlds-formulation-of-quantum-mechanics-is-probably-correct/> . So that is all there is to it. What is more than just not having one world? @philipthrift -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/4c621065-efc2-4934-97c3-70ea1156544e%40googlegroups.com.
