From: *Bruno Marchal* <[email protected] <mailto:[email protected]>>
On 8 Aug 2018, at 01:39, Bruce Kellett <[email protected]
<mailto:[email protected]>> wrote:
From: *Bruno Marchal* <[email protected] <mailto:[email protected]>>
If there is a FTL physical influence, even if there is no
information transfer possible, it leads to big problems with any
reality interpretation of special relativity, notably well described
by Maudlin. Maudlin agrees that many-mind restore locality, and its
“many-mind” theory is close to what I think Everett had in mind, and
is close to what I defended already from the mechanist hypothesis.
To be sure, Albert and Lower Many-Minds assumes an infinity of mind
for one body, where in mechanism we got an infinity of relative body
for one mind, but the key issue is that all measurement outcomes
belongs to some mind. The measurement splits locally the observers,
and propagate at subliminal speed.
I don't think that the many-minds interpretation is really what you
would want to support. In many-minds, the physical body is always in
the superposition of all possible results, but the 'mind' can never
be in such a superposition,
That sides with Mechanism. In arithmetic there is an infinity of
identical (at the relevant representation level) brains. Now Albert
and Loewer seems to associate an infinity of mind with one body.
The 'infinity of minds for each body' was postulated by Albert and Lowe
to avoid the 'mindless hulk' problem. In other words, it was just an /ad
hoc/ fix for a problem in the theory. This alone should have been
sufficient to render the theory unacceptable.
I do not understand this, and with the Mechanist “many-dreams” it is
the contrary: each mind as an infinity of (virtual) bodies, and the
consciousness will differentiate along their computational different
continuations. Take the WM-duplication. After the reconstitution, but
before the copies open the door, one mind is associated to two bodies,
and then differentiates in W or in M from each location perspective.
To say that the mind is not in a superposition is equivalent with
Everett’s justification that the observer cannot feel the split, and
it is where Everett use (more or less explicitly) the mechanist
hypothesis.
The splitting in Everett's theory at least makes some sort of sense, and
is not postulated /ad hoc/. The real problem I see with many-minds
theory is that it does not actually explain the observed correlations.
The correlations are presumed not to exist in reality -- all possible
combinations of experimental outcomes happen, but when Alice and Bob
meet, their bodies are still in indefinite states -- no actual results
are recorded by entanglement with their bodies -- but their minds will
be in definite states that agree with the quantum correlations. This
step seems to introduce yet more unreasonable magic into the
'explanation'. Why are the minds like this when they communicate?
Especially since there are pairs of observers who get results that do
not agree with QM (the 'mindless hulks!').
Maudlin moved on in the years between the first edition of his book in
1994 and the third edition in 2011. In his 2011 thinking I can only
imagine that he would have seen many-minds in much the same way as he
later saw many-worlds -- if appeal is made to the wave function to make
sense of the correlations in many-worlds, then we have to recognize that
this is not a /local/ account since the wave function is not a local
object. The same can clearly be said of the many-minds approach.
The wave function is not local because the entangled singlet state is
non-separable. Non-separability means that if you interact with one part
of the state, you affect the whole state: the state cannot be split into
separate non-interacting parts, one for each particle in the singlet.
That is why the non-locality is unavoidable -- in many minds as in
many-worlds -- it is an intrinsic part of quantum theory, and is perhaps
the most significant way in which quantum mechanics differs from
classical mechanics (you don't get non-separable states in classical
mechanics, although you do get interference between classical waves).
so stochastically chooses to record only one definite result from the
mix. In the Wikipedia article on the many-minds interpretation, the
following comment might be relevant for you:
"Finally, [many-minds] supposes that there is some physical
distinction between a conscious observer and a non-conscious
measuring device, so it seems to require eliminating thestrong
Church–Turing hypothesis
<https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis#Philosophical_implications>or
postulating a physical model for consciousness.”
What does they mean by “Strong Church-Turing hypothesis”?
I imagine that the Wikipedia author means that the strong CT hypothesis
supposes that the world is nothing more than a computation.
The above sentence does not make sense. The many-worlds theory is a
direct consequence of the SWE + the mechanist theory theory of mind.
It is the collapse of the wave which would be threat to Mechanism (and
of Rationalism).
If machines can do something that the mind cannot do (viz., be in a
superposition of all possible results, when the mind cannot
participate in any such superposition),
The mind cannot NOT participate to the infinite superposition which is
not eliminable from arithmetic. That is why we have an infinity of
body in arithmetic, and why when we look closely to the environment,
i.e. below our mechanist substitution level, we must find the sign of
the presence of the alternate computations, like QM-without-collapse
confirmed.
So, contrary to what you said above, you do not really agree that the
supposedly local 'many-minds' account given by Maudlin in his book is
close to what you think?
the Church-Turing thesis goes out the window -- and you might not
want to say "Yes, Doctor".
I think the complete opposite of this is correct. Church’s thesis go
hand in hand with the non collapse (and non guiding potential) of the
quantum wave. The only problem that Everett missed, is that, for all
this to be consistent, extract the formalism of the Wave itself from
the statistic on all computations. Then the logic of machine
self-reference and its variants imposed by incompleteness gives the
complete solution at the propositional level, and that works, in the
sense that we get quantum logic where we should, making Mechanism not
(yet) refuted by observations.
But that is your theory of mechanism, which is not to be found in
quantum theory at all.
Bruce
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