On 22/11/2017 9:36 am, John Clark wrote:
On Tue, Nov 21, 2017 at 12:22 AM, Bruce Kellett
<[email protected] <mailto:[email protected]>>wrote:
>>
AT LEAST one of the following properties of that theory must
be untrue:
1) Determinism
2) Locality
3) Realism
>
You have repeated this claim several times, John, but it is not
strictly true. Maudlin summarizes it like this:
"Early on, Bell's result was often reported as ruling out
/determinism/, or /hidden variables/. Nowadays, it is sometimes
reported as ruling out, or at least calling in question,
/realism/. But these are all mistakes. What Bell's theorem,
together with the experimental results, proves to be impossible is
not determinism or hidden variables or realism, but /locality, /in
a perfectly clear sense/. /What Bell proved, and what theoretical
physics has not yet properly absorbed, is that the physical world
itself is non-local."
a
He's right, Bell didn't rule
out determinism
or realism,
but if you insist on both there is a
high
price that must be payed, non-locality
;
but Maudlin
can't seem to get a grip on Many worlds and can't decide if its a
local theory or not.
No, it seems that for Maudlin MWi is essentially incoherent because it
cannot come to grips with a sensible account of probabilities. All
attempts to derive probabilities and the Born rule in MWI have been
shown to be circular. Maudlin talks a little more about this in his book.
And
B
ell isn't the only problem, we now know that the Leggett–Garg inequality
is also violated and that means the non-locality must be even stranger.
I found the paper arxiv:0806.2037 largely incomprehensible. I do not
know what the authors here mean by 'realism', much less 'crypto
non-local realism'.
It certainly seems to me, and Maudlin gave me no reason to think
otherwise, that if things are not realistic, if a photon is neither
horizontally nor vertically polarized until I measure it, if things
don't fully exist till I observe it them
,
then things can be local,
You mean that a local hidden variable account can be given in that case?
Lapiedra et al. seem to suggest that Bohm's theory cannot work in their
case, but I think their implementation of an 'arrow of time'
consideration is not really aplicable in the case of space-like
separation -- time order is not defined in that case, so there is no
'arrow of time'.
although I would be unable even in principle to
determine
with 100%
certainty
what
the
electron will do because that depends on what I do and I won't know
what that is until I do it.
He does mention the Superdeterminism
loophole and I do admit you could have all 3 with that
,
but its hard for me to take it seriously because the the initial
conditions of the universe would have to be in a very very very
specific and rare state. Maybe the conditions 13.8 billion years ago
were set up in such a way that today I had to
place
my polarizing filter in a horizontal direction set up in such a way
that Bells inequality was violated but things are still local and
realistic.
Maybe its pointless to even ask what would have happened it I had
set it vertically instead because there is no way I could have done
it, it was preordained 13.8 billion years ago that I would set it
horizontally and doing otherwise would violate the laws of
deterministic physics.
Maybe the universe is a put up job set up just to fool us, but I doubt it.
I agree that superdeterminism as suggested by 't Hooft is contrived, and
very unlikely to be the case in reality.
Bruce
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