On 3/4/2020 2:43 PM, Bruce Kellett wrote:
On Thu, Mar 5, 2020 at 9:15 AM 'Brent Meeker' via Everything List
<[email protected]
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On 3/4/2020 1:54 PM, Bruce Kellett wrote:
On Wed, Mar 4, 2020 at 11:01 PM Stathis Papaioannou
<[email protected] <mailto:[email protected]>> wrote:
Probability derived from self-locating uncertainty is an idea
independent of any particular physics. It is also independent
of any theory of consciousness, since we can imagine a
non-conscious observer reasoning in the same way. To some
people it seems trivially obvious, to others it seems very
strange. I don’t know if which group one falls into
correlates with any other beliefs or attitudes.
As I said, self-locating uncertainty is just another idea imposed
on the quantum formalism without any real theoretical foundation
-- "it is just imposed by fiat on a deterministic theory." If
nothing else, this shows that Carroll's claim that Everett is
just "plain-vanilla" quantum mechanics, without any additional
assumptions, is a load of self-deluded hogwash.
Whether MWI is a satisfactory interpretation or not; do you have a
preferred proposal for getting rid of the unobserved macroscopic
states that are predicted by the formalism with a collapse
postulate, e.g. gravitationally induced collapse, transactional
interpretation, or what?
I do not think the problem is solved at the moment. Penrose's
gravitational induced collapse still lacks a dynamical mechanism for
the collapse when the gravitational superposition become unwieldy.
Have you looked at Laloe's paper which fills this in using some Bohmian
ideas. arXiv:1905.12047v3 [quant-ph] 6 Sep 2019
Cramer's (Kastner's) transactional interpretation introduces a whole
new "possibility world", and relies on the failed absorber theory of
radiation.
I think the function of the possibility space is to avoid the problems
of the absorber theory. The absorbtion is "transacted" in possibility
space. I'm note sure how it handles free radiation (e.g. the CMB) since
nothing happens except by an exchange of energy/information between an
emitter and absorber.
No-go there. Bohm is the preferred option of many philosophers of QM,
but I think Flash-GRW is growing in plausibility. At least it does
give an underlying stochastic dynamics, so doesn't suffer the problems
of introducing probability that other approaches have.
It is still an open question, as far as I can see. The clear thing is
that Everett plainly fails to make any sense of probability when all
outcomes occur for any measurement.
I don't see that as particularly damning. I just means you need another
postulate of the form "And /this/ is a probability measure." For
example, if you take Zurek's quantum Darwinism to provide an objective
pointer basis then you can say, in this basis, off-diagonal terms in the
reduced density matrix that are so small they will never be observed can
be set to zero and then the diagonal terms are just the probability of
the (one) world that will be actual.
Brent
Bruce
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