On 14/08/2017 11:19 am, Stathis Papaioannou wrote:
On Mon, 14 Aug 2017 at 10:30 am, Bruce Kellett
<bhkell...@optusnet.com.au <mailto:bhkell...@optusnet.com.au>> wrote:
On 14/08/2017 2:51 am, Stathis Papaioannou wrote:
On Sun, 13 Aug 2017 at 9:38 pm, Bruce Kellett
<bhkell...@optusnet.com.au <mailto:bhkell...@optusnet.com.au>> wrote:
I think the problem I see is in the insistence that one
restrict the subjects of the duplication to first person
knowledge. Their knowledge of the protocol cannot be purely
1p -- there has to be a 3p component in that they are told
the set up, and they have sufficient background 3p knowledge
to trust the operator, etc. Then, after duplication, they
also have access to 3p knowledge about both duplicates --
they can arrange to communicate, for example. So they can
easily become aware of the fact that the person that
remembers being Helsinki man sees both Moscow and Washington.
My point here is that if you restrict them to 1p knowledge
after the duplication, you must, in order to be consistent,
restrict them to just 1p knowledge before the experiment; in
which case they are necessarily unaware of the details of the
protocol and will have a different perception of what has
happened.
In the case of restriction to 1p knowledge the situation
becomes much more analogous to what happens in QM where
experiments might have multiple outcomes. In that case there
is no possibility of communication between the different
branches of the wave function, so there is genuine
uncertainty about outcomes, and probabilities are estimated
from limiting relative frequencies in the usual way. If one
derives and/or applies the Born Rule in QM, then one can
assign low probabilities to untypical sequences of results
and the like. If you mix 1p and 3p knowledge in the
duplication scenario, you lose this parallel with QM because
the analogous 3p knowledge is not available in QM.
If someone believes the MWI is true, then he is aware of the
protocol and trusts the operator. In duplication experiments
there is no logical reason why the copies could not be kept
ignorant of each other
And there is no logical reason that prevents them from arranging
beforehand to communicate after the experiment -- in Helsinki, I
could decide to post my subsequent location to Facebook, and
communicate with other similar posts.
But if they were prevented from communicating would it make any
fundamental difference to the experiment?
and there is no logical reason why copies in the MWI can't see
what each other is doing.
Such inter-branch communication in MWI is physically impossible.
This is the main reason why person duplication experiments can
never emulate QM, MWI or not.
It is physically impossible, but what fundamental difference would it
make if you could communicate with a copy in a parallel world who
diverged from you a while ago? Would you suddenly feel that you
weren't you, or that you were in two places at once?
The ability to communicate, or the physical impossibility of such
communication, is the fundamental difference between the duplication
scenario and quantum MWI. It changes the probabilities: just think of
duplication of the apparatus in a spin measurement experiment without
simultaneous duplication of the experimenter -- then it is clear that I
get both spin up and spin down, in my laboratory, in front of my eyes.
This is not possible in MWI since the branches are, by definition,
non-interacting.
Bruce
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