On Apr 16, 4:54 am, Bruno Marchal <marc....domain.name.hidden> wrote:
> Le 16-avr.-08, à 03:24, Russell Standish a écrit :
> > On Wed, Apr 16, 2008 at 02:22:23AM +0200, Saibal Mitra wrote:
>
> >>> First off, how is it that the MWI does not imply
> >>> quantum immortality?
>
> >> MWI is just quantum mechanics without the wavefunction collapse
> >> postulate.
> >> This then implies that after a measurement your wavefuntion will be
> >> in a
> >> superposition of the states corresponding to definite outcomes. But we
> >> cannot just consider suicide experiments and then say that just
> >> because
> >> branches of the wavefuntion exist in which I survive, I'll find
> >> myself there
> >> with 100% probability. The fact that probabilities are conserved
> >> follows
> >> from unitary time evolution. If a state evolves into a linear
> >> combination of
> >> states in which I'm dead and alive then the probabilities of all these
> >> states add up to 1. The probability of finding myself to be alive at
> >> all
> >> after the experiment is then less than the probability of me finding
> >> myself
> >> about to perform the suicide experiment.
>
> >> The probability of me finding myself to be alive after n suicide
> >> experiments
> >> decays exponentially with n. Therefore I should not expect to find
> >> myself
> >> having survived many suicide experiments. Note that contrary to what
> >> you
> >> often read in the popular accounts of the multiverse, the multiverse
> >> does
> >> not split when we make observations. The most natural state for the
> >> entire
> >> multiverse is just an eigenstate of the Hamiltonian. The energy can
> >> be taken
> >> to be zero, therefore the wavefunction of the multiverse satisfies the
> >> equation:
>
> > One should also note that this is the ASSA position. The ASSA was
> > introduced by Jacques Mallah in his argument against quantum
> > immortality, and a number of participants in this list adhere to the
> > ASSA position. Its counterpart if the RSSA, which does imply quantum
> > immortality (provided that the no cul-de-sac conjecture holds), and
> > other list participants adhere to the RSSA. To date, no argument has
> > convincingly demonstrated which of the ASSA or RSSA should be
> > preferred, so it has become somewhat a matter of taste. There is some
> > discussion of this in my book "Theory of Nothing".
>
> Actually, I am not sure the ASSA makes sense once we take into account
> the distinction between first and third person point of view. Comp
> immortality is an almost trivial consequence that personal death cannot
> be a first person experience at all. Quantum immortality is most
> plausibly equivalent with comp immortality if the "quantum level"
> describes our correct comp substitution level. But this does not mean
> that we can know what shape the comp immortality can have, given that
> comp forbids us to know which machine we are or which computations bear
> us.
Why is this the case? Whether Comp is true or not, it would seem that
the direction of physical research and investigation is in the
direction of discovering the presumed foundational TOE that accounts
for everything we observe. Say, for example, that it were possible to
create in a computer simulation an artificial universe that would
evolve intelligent life forms by virtue of the "physics" of the
artificial universe alone. Why, in principle, is it not possible for
those intelligent beings to discover the fundamental rules that
underlie their existence? They will not be able to discover any
details of the architecture of the particular turing machine that is
simulating their universe (even whether or not they are in fact being
computed), but I don't see any a priori reason why they would not be
able to discover their own basic physical laws.
Max Tegmark has indicated that it may be possible to get some idea of
which mathematical structure bears our own existence by approaching
from the opposite direction. Though we may never know which one
contains ourselves, it may be possible to derive a probability
distribution describing the likelihood of our location in the
ensemble.
To go back to the comments you were making about the Prestige:
If the subject of a quantum immortality experiment finds himself
improbably alive, is he in some sense guilty of the murder of the
other versions of himself? Or not, since those are merely third person
experiences. What constitutes a first person experience? It seems that
you are defining it as an uninterrupted consciousness since comp
implies the "almost trivial consequence that personal death cannot be
a first person experience at all." I am confused by exactly what is
meant by first and third person experiences.
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Received on Wed Apr 16 2008 - 12:02:58 PDT