On 02 Nov 2015, at 06:17, Bruce Kellett wrote:
On 2/11/2015 4:53 am, Bruno Marchal wrote:
On 30 Oct 2015, at 01:17, Bruce Kellett wrote:
On 30/10/2015 3:47 am, Bruno Marchal wrote:
On 27 Oct 2015, at 06:54, Bruce Kellett wrote:
On 27/10/2015 9:37 am, Russell Standish wrote:
The only clarification I would make is that (with
computationalism) the system is formal, but the observer
(individual in your terminology) and environment (universe with
its physics in your terminology) are a non formal partition of
the system.
How is that partition into observer and universe made? If it is
purely formal then it doesn't do the necessary work. But then,
how does a purely formal system generate a non-formal division?
I think your division builds in semantic content from the
outside by fiat -- not in a principled way.
This is similar to my objection to the many worlds
interpretation of QM. You have to distinguish between the
different worlds in some way -- unitary evolution cannot do
this. Decoherence always leaves residual correlations, and
although these may be small, there are a very large number of
them, so the original superposition is, in fact, still intact.
Everett wants to make the world relative to the particular
observer (hence 'relative state' interpretation). But to make
sense of this mathematically you have to get rid of the unwanted
correlations.
I don't see why. We can fuse again by amnesia, and exploit the
unwanted correlation. They disappears only relatively, nothing is
lost, evolution is time symmetric.
No, amnesia does not reconnect the separate worlds -- it merely
indicates a confused individual. The world is not defined by what
one person sees or thinks. Inter-subjective agreement is essential
to understanding what is going on. You confuse the 1p and 3p, yet
again.
?
Most do this by fiat -- the worlds are orthogonal FAPP. But that
is not principled either. Mathematically, we take a partial
trace. But we take the trace, it is not in Schroedinger's
equation.
It is in the relative choice made by our histories (long
computations), relatively to us. Zurek explains this rather well
in my opinion, I mean why our type of brain needs orthogonal
positioning, why position is favored by brain-like structures,
for consciousness to stabilize enough to make prediction in our
deep environment(universal computations).
Zurek does not explain the point that I am making. Zurek's
einselection is designed to explain the preferred basis problem.
But he misses the mark by quite a wide margin. He explains why the
position operator is often relevant, but that merely selects a
Hilbert space, it does not select a basis in that space.
?
If you do not understand that, then you need a refresher course in
linear algebra and vector spaces.
The basis has to be robust against environmental interactions, not
just the operator itself. Einselection, like decoherence, is part
of the solution, but it is not the full solution.
But even if you have actually solved the basis problem, you still
have not solved the problem of quantum measurement. In order to
get just one result for an experiment with only probabilistic
results, you have to project a subspace out of the full Hilbert
space.
You get it by the indexical FPI, so you can define it in
arithmetic, and in QM, with the usual machine's self-reference (à-
la Gödel).
Which is just your idiosyncratic way of saying that we have to apply
a projection operator.
No, we have to recover the "projection operator" from the
computationalist quantization. It is a math problem.
The trouble with your FPI approach is that it does not explain the
inter-subjective agreement that is an essential part of our
experience. All people experience the same "classical" world (in
which they agree about the observed basis vectors that are robust
against environmental decoherence)
The indexical quantization provides the path toward the solution or
the lack of solution. Don't confuse the intuitive FPI of the UDA, and
its translation in math based on the Gödel-Post-Turing-Kleene technic
which makes the self-reference mathematically precise.
The full space might well still be 'there' (in whatever sense you
like), but the fact that the observer is conscious of only part of
that space involves a projection operator. And projection
operators are not time symmetric or unitary. This is the partial
trace problem, and it remains unsolved.
It is exactly what Everett solved, assuming mechanism, by taking
into account the personal point of view of the isolated system with
respect to what it is isolated and not isolated. Everett shows this
does not depend on the bases.
He showed no such thing. The basis according to which the
"classical" world is projected out is absolutely crucial. We would
not observe the same world in any other basis. The basis we do
observe is the one that is robust against environmental decoherence
-- any other basis is not robust, so rapidly devolves into the
robust (einselected) basis.
The choice of the bases is what Zurek have explained. That extends
Everett.
It corresponds with the eigen value of the frequency operator,
justifying the "squaring" of the amplitude (something seen by
Paulette Février-Destouches, a student of De Broglie, and by
Finkelstein).
It is not solve for a computationalist as we have to justify the
ortho-structure, but we get one (well, 3) at the propositional
level already.
This is incoherent.
You might elaborate, as I have no clue why you says this.
Bruno
Bruce
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