On Mon, Nov 18, 2024 at 11:14:16AM +1100, Bruce Kellett wrote:
On Mon, Nov 18, 2024 at 10:35 AM Russell Standish <[email protected]>
wrote:
On Mon, Nov 18, 2024 at 10:05:56AM +1100, Bruce Kellett wrote:
> On Mon, Nov 18, 2024 at 9:30 AM Russell Standish <[email protected]>
wrote:
>
> On Sat, Nov 16, 2024 at 03:52:25PM +1100, Bruce Kellett wrote:
> >
> > On Sat, Nov 16, 2024 at 3:28 PM Russell Standish <
[email protected]>
> wrote:
> >
> > On Sat, Nov 16, 2024 at 03:08:03PM +1100, Bruce Kellett wrote:
> > > On Sat, Nov 16, 2024 at 2:41 PM Russell Standish <
> [email protected] wrote:
> > >
> > > I don't think it requires this assumption. In fact
"physically
> real"
> > > is a rather nebulous concept anyway.
> > >
> > >
> > > If you want the 'other worlds' to be physically real, then
the original wave
> > > function must be physically real.
> >
> > That's a non-sequitur. The 'other worlds' are as real as this
one. The
> > reality of the wave function doesn't enter into it.
> >
> >
> > It does if the wave function is purely epistemic. In other words,
if it is
> > merely a means of calculating probabilities, then the supposed
'other worlds'
> > do not exist. The probabilities are the probability that one, and
only one,
> > outcome is realized for each experiment.
>
> You've lost me here. Even if the wf is epistemic, it has no bearing
on
> whether other branches are as real as this one or not.
>
>
> It does have a significant bearing on the reality of the other branches.
One of
> the frequently stated arguments for many worlds is that it avoids the
problem
> of the wave function collapse. The collapse of the wave function is only
a
> problem if the wave function is a physical object, because then you run
into
> problems with instantaneous action at a distance or FTL physical action.
If the
> wave function is purely epistemic, namely, nothing more than a summary of
our
> knowledge about the physical system, there is no problem with collapse,
because
> the result of an experiment merely updates our knowledge, and the wave
function
> is updated to reflect this change in knowledge. This is exactly what
happens in
> classical probability.
>
> If the wave function is purely epistemic, there is no problem with
collapse,
> and the additional worlds that MWI introduces play no useful role and can
> readily be discarded. The other worlds need be real only if the wave
function
> itself is real, and some way of avoiding a physical collapse is required.
Once
> you avoid the collapse problem, the many-worlds scenario becomes otiose.
I do agree with you that an epistemic wave function has no problem
with collapse, but I've always said the collapse issue was rather
secondary compared with the issue of what privileges one branch over
all the others as being "real".
Not a problem if the branches do not exist. All we have on the epistemic
interpretation is the probabilities that the future will be one way or another.
Stating that all branches are equally real with the one we observer
obviates the need for something to say one branch is more real than
the others, without committing to saying whether anything is real, or
even what "real" really means.
But there are no branches to be "equally real". You are fond of calling sound
arguments "non sequitur".
If the arguments were sound, I would not call them non-sequitur. There
is the possibility I missed something you consider obvious, but in
that case, I just ask you to dig deeper to join the dots.
Your claim that all branches are equally real is
indeed a non sequitur, in that it does not follow from anything at all.
Indeed. As is that there is only a single reality. But one is simpler than
the other. A lot of people get Occam's razor wrong here.
But my claim was "Stating that all branches are equally real with the
one we observe [sic] obviates the need for something to say one branch is
more real than the others". This is a pretty logical statement, some
would say of the bleeding obvious, but it does seem necesseary to point it
out.
In contrast to your last statement, I find "single world
interpretations" otiose, in much the same way as I find Christian
theology otiose.
That is among the sillier remarks that you have made.
In order to have a single world interpretation, you need a something
that privileges that single world. It is remarkably analogous to
saying "God did it", and equally as mysterious. It is certainly not
intended as a silly remark.
