On 26 Feb 2015, at 05:36, meekerdb wrote:
On 2/25/2015 7:11 PM, Jason Resch wrote:
On Wed, Feb 25, 2015 at 5:28 AM, Bruce Kellett <[email protected]
> wrote:
Bruno Marchal wrote:
On 24 Feb 2015, at 22:52, Bruce Kellett wrote:
MWI simply formalizes the fact that such data are "in-principle
unknowable".
Well, usually we say that the SWE formalizes that fact, and that
the MWI interpret this in term of many world. But I am OK with your
statement, as SWE implies formally the MWI,
Statements like this are gaining in currency these days, but this
is strictly false. The SWE operating on vectors in Hilbert space
does not formally imply the MWI. All that the formalism implies is
the existence of superpositions. Schroedinger realized this very
early on, hence his example of the cat being in a superposition of
dead and alive states. Schroedinger thought this was effectively a
reductio ad absurdum for the wave equation.
I'm not so sure. I think he was more attacking the role of the
observer in creating reality. We see Einstein affirm this in a
letter to Schrodinger:
Einstein was most impressed with Schrödinger's paper, and in 1950
wrote Schrödinger a letter of praise, saying “You are the only
contemporary physicist, besides Laue, who sees that one cannot get
around the assumption of reality, if only one is
honest. Most of them simply do not see what sort of risky game they
are playing with reality—reality as something independent of what
is experimentally established. Their interpretation is, however,
refuted most elegantly by your system of radioactive atom +
amplifier + charge of gunpowder + cat in a box, in which the psi-
function of the system contains both the cat alive and blown to
bits. Nobody really doubts that the presence or absence of the cat
is something independent of the act of observation.”
Further, we see that later in his life, Schrodinger began to take
his theory (and the reality of the super position) more seriously:
“Schrödinger also”, David Deutsch notes, “had the basic
idea of parallel universes shortly before Everett, but he didn't
publish it. He mentioned it in a lecture in Dublin, in which he
predicted that the audience would think he was crazy. Isn't that a
strange assertion coming from a Nobel Prize winner—that he feared
being considered crazy for claiming that his equation, the one that
he won the Nobel Prize for, might be true.”
In order to get MWI one has to add a lot more superstructure. In
particular one has to solve the basis problem and give a plausible
account of the meaning of probabilities in a theory in which every
possible result actually occurs. Both of these areas are still
matters of substantial debate.
Tegmark shows in a large enough world, even under something like
the CI, you can't escape "all possibilities being realized", so
you're faced with the same probability "problem" whether you think
the wave function collapses or not: http://arxiv.org/abs/1008.1066
We study the quantum measurement problem in the context of an
infinite, statistically uniform space, as could be generated by
eternal inflation. It has recently been argued that when identical
copies of a quantum measurement system exist, the standard
projection operators and Born rule method for calculating
probabilities must be supplemented by estimates of relative
frequencies of observers. We argue that an infinite space actually
renders the Born rule redundant, by physically realizing all
outcomes of a quantum measurement in different regions, with
relative frequencies given by the square of the
wave function amplitudes.
if we define world by a structure of events close for interaction.
Then, using the FPI, we have a dterlministic and local account of
why the data appears for the observer first person (plural) point
of view as unknowable, indeterminist and non local.
Maybe the data appear indeterministic and unpredictable in
principle because they really are that way -- the world is governed
by probabilistic laws. We don't actually need all the
superstructure of MWI.
What do you find more appealing, elegant, and historically more
likely to be true:
1. A large number of objects implied to exist by a simpler theory
2. A small or singular number of objects as described by a more
complex theory
MW is just what's left over when you dispense with the ill-
conceived and ill-defined notion of collapse: the only phenomenon
in all science that's not time-symmetric, not time-reversible,
nonlinear, discontinuous, non-deterministic, non-local, and
observer dependent. I'll take the many worlds before I take that.
But without solving the measure and basis problem, MWI doesn't
predict anything - or more accurately, it predicts everything.
MWI predicts the same as QM+collapse.
It is just that MWI dispense with magic. It is local, deterministic,
realist (even if multi-realist).
It simply pretends to dispense with collapse while sneaking in its
equivalent in order to use the Born rule.
It uses only the comp FPI, or variant. It is consciousness selection,
with relative measure.
It is radically non-local.
It appears to be so in each branches, but is not when you look at all
branches partition, and this in any base. Paper showing that MWI is
non local adds metaphysical baggage which is not in QM, nor in Everett.
There are plenty of phenomenon in science that are non-linear.
Not in the reality, if the reality is described by quantum mechanics.
But non linearity appearance is explained from inside + ignorance of
the other branches.
Computationalism is also discontinuous.
It depends of the topology. Computation = continuous with the relevant
toplogies of computer science. It is only discontinuous in topology of
reals, which is another subject.
Self-localization in FPI is observer dependent; but whatever theory
adopted it needs to save the phenomenon of observation.
OK.
Quantum bayesianism is directly a theory of observation.
Why not? That is not a problem in the MWI.
Bruno
Brent
Brent
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