I think this illustrates how an observation is one a deep level a sort of self-observation or about a set of quantum numbers that encode themselves. For this reason there is then no complete and consistent way of reconciling the quantum and classical worlds with each other according to quantum postulates. For this reason there are these various quantum interpretations with a range of strengths and weaknesses that are not consistent with each other. We might think of these as something we intend to make quantum mechanics more complete, but we then end up with various drafts of extended QM that are not consistent with each other.
LC On Saturday, December 16, 2017 at 12:00:30 PM UTC-6, John Clark wrote: > > On Thu, Dec 14, 2017 at 9:20 PM, <[email protected] <javascript:>> > wrote: > > > >> I don't see how Wigner's friend presents a problem for Copenhagen. >> According to the CI, the wf collapses when the system measured, which is >> when the box is opened. What am I missing? >> > > > According to > > Copenhagen > > Wigner's friend > > opens the cat box and that > > collapses > > the cat's wave function, and so Wigner's friend > > now knows the cat's fate, but Wigner's friend > > is also in a box and Wigner > > himself is outside that box, so until Wigner opens his friend's box his > friend is in a "I see a dead cat" state AND a "I see a live cat state". > And of course you could put Wigner himself in a box with somebody outside > it and you could keep increasing the number of nested boxes until the > entire universe is included, and that is why the Copenhagen > > interpretation is useless if you're > interest is in > dealing in cosmology because there is nobody outside > to > universe observe it. > > And God > is of no help unless somebody knows who collapses God's wave function, > and even then there would be another unanswered question too obvious to > mention. > > John K Clark > > > > -- 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.
