On Wed, Oct 9, 2019 at 2:48 PM 'Brent Meeker' via Everything List < [email protected]> wrote:
> On 10/8/2019 5:47 PM, Bruce Kellett wrote: > > On Wed, Oct 9, 2019 at 11:42 AM 'Brent Meeker' via Everything List < > [email protected]> wrote: > >> On 10/8/2019 5:07 PM, Bruce Kellett wrote: >> >> On Wed, Oct 9, 2019 at 10:24 AM 'Brent Meeker' via Everything List < >> [email protected]> wrote: >> >>> >>> On 10/8/2019 2:59 PM, Philip Thrift wrote: >>> >>> That sounds reasonable. Indeed, it is reasonable. It is just as >>> reasonable as the measurement postulate. In fact, it is logically entirely >>> equivalent to the measurement postulate. >>> >>> >>> It's not clear here what "logically" equivalent means. It is >>> instrumentally equivalent...which is why it's an interpretation and not a >>> different theory (as GRW is). It's different from the measurement >>> postulate in that the measurement postulate says the wave function >>> instantaneously changes to match the observed measured value. MWI says >>> those other measured values obtain in other orthogonal subspaces of the >>> Hilbert space and you are only observing one. Those are not "logically" >>> the same. >>> >> >> What do you mean by "logically equivalent"? It seems to me that if two >> assumptions fulfil the same explanatory role -- they are functionally >> equivalent -- then it is sensible to call them "logically equivalent". They >> fulfil the same logical role in the argument. >> >> >> I mean X=>Y and Y=>X. But MWI entails some things that CI doesn't and >> vice versa. In the C60 buckyball experiment CI doesn't give a very >> satisfactory account, because it doesn't have a good definition of >> "measure". MWI introduced the idea of decoherence to fulfill that role >> without actually requiring a human observer. >> > > That explanation of "measurement" is every bit as available to the CI > theorist as to the Everettian theorist. As Peter Woit pointed out a while > back, there is not much different between Everett and Copenhagen. Both can > work with "its quantum all the way down", and develop the same > understanding of "measurement". There is nothing particularly "many worlds" > in the notion of decoherence. > > > But at some point where MWI says we can ignore the other "worlds", CI says > the wf collapses...implying collapse is a physical process. > Maybe the difference is just a metaphysical quibble -- and I eschew metaphysical quibbles. :-) Bruce -- 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/CAFxXSLR7%3DLJT7P7zMYBm2TMnVpC_S62i_qafRqiqb-oiyAgU-Q%40mail.gmail.com.
