On Thu, Jun 21, 2018 at 1:02 AM, Brent Meeker <[email protected]> wrote:
> > > On 6/20/2018 9:50 PM, Jason Resch wrote: > > > > On Tue, Jun 19, 2018 at 5:47 PM, Brent Meeker <[email protected]> > wrote: > >> >> >> On 6/19/2018 8:16 AM, Bruno Marchal wrote: >> >>> Most of these objections to CI are answered by decoherence theory. >>>> >>> >>> I have no clue how to interpret decoherence with a collapse theory. >>> >> >> You use decoherence theory until you get to the reduced density matrix >> that is diagonal FAPP (or for all conscious purposes) and then you declare >> it is exactly diagonal and cut the other "worlds" loose. > > > > What's the point of that last step, when decoherence explains why we don't > see those other branches? > > > But decoherence didn't quite explain it. You have to take the trace over > the environment in order to justify making the reduced density matrix > exactly diagonal (instead of FAPP diagonal) and that step is not unitary > evolution per the SE, it's using a projection operator. > Wouldn't this imply that Everett failed in his relative state formulation and that the collapse postulate is still necessary to explain observations? 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
