Re: Macroscopic Emergence in MWI worlds

--- In [email protected], Alan Forrester <alanmichaelforrester@...> wrote:
>
> On 19 August 2013 21:57, Gary Oberbrunner <garyo@...> wrote:
> > On Mon, Aug 19, 2013 at 3:53 PM, hibbsa <hibbsa@...> wrote:
> >>
> >>
> >> --- In [email protected], David Deutsch <david.deutsch@>
> >> wrote:
> >> > On 19 Aug 2013, at 16:55, hibbsa <hibbsa@> wrote:
> >> >
> >> > > So the problem is, MWI has basically has no macroscopic influence.
> >> >
> >> > Compared with what?
> >>
> >> compared to most all major scientific theories I should think. Even QM
> >> minus mwi is hugely influential since it is probably behind a large amount
> >> of the emergence that creates macroscopic reality.
> >>
> >
> > Isn't "QM minus MWI" = Copenhagen?  In other words by "subtracting" MWI,
> > you're really adding in the collapse postulate, since MWI is just QM
> > without collapse.
> >
> > Are you really just saying that MWI is untestable?  I.e. that it doesn't
> > make an refutable predictions?  That's a valid criticism.  I think IF we
> > can build a large-scale quantum computer, such that it can do more than a
> > theoretical perfectly efficient computer occupying the same spacetime, that
> > would be a refutation of Copenhagen, since all that computation has to be
> > done somewhere.
> 
> The CI makes no predictions. The CI makes ad hoc modifications of QM
> and the precise details of what predictions QM will make depend on the
> precise details of the modifications. But there is no explanation of
> those precise details because if such an explanation existed the
> theory wouldn't be ad hoc. So the CI makes no predictions.
> 
> For example, if the wave function collapses the precise of details of
> where and how that happens will affect the results of experiments. But
> the problem of why we can't see other versions of objects around us
> has been solved by decoherence, so there is no need for the collapse
> and no explanation of where and how it happens.
> 
> As a result, the CI can't be used to explain anything about emergence.
> The other "interpretations" of QM have similar problems.
> 
> You are laying the blame for the untestability of other
> interpretations on the MWI. This is analogous to saying that modern
> cosmology is untestable when compared to creationism and this is a
> fault in evolution.

The only testability I have heard you mention amounted to claiming QM's accomplishments for MWI. Is that still all it is, or is the standard higher now? 

> predictions: God could have made the universe 6000 years ago (or five
> minutes ago, or two seconds ago, or he could make and destroy the
> universe every time the number of seconds since the Big Bang is a
> prime number, or...) and made it look like it is billions of years
> old. That's not a fault in modern cosmology.
> 
> Alan
>