On 09 Sep 2015, at 09:03, Stathis Papaioannou wrote:
On 9 September 2015 at 15:40, Brent Meeker <[email protected]>
wrote:
On 9/8/2015 8:29 PM, Jason Resch wrote:
On Tue, Sep 8, 2015 at 9:44 PM, Bruce Kellett <[email protected]
> wrote:
On 9/09/2015 12:26 pm, Stathis Papaioannou wrote:
On 9 September 2015 at 10:43, Bruce Kellett <[email protected]
> wrote:
On 9/09/2015 9:30 am, Stathis Papaioannou wrote:
On 9 September 2015 at 09:23, Bruce Kellett <[email protected]
> wrote:
On 9/09/2015 8:56 am, Stathis Papaioannou wrote:
On 8 September 2015 at 22:11, Bruce Kellett <[email protected]
> wrote:
On 8/09/2015 9:14 pm, Stathis Papaioannou wrote:
On 8 September 2015 at 20:48, Bruce Kellett <[email protected]
> wrote:
On 8/09/2015 8:40 pm, Stathis Papaioannou wrote:
On 8 September 2015 at 17:39, Bruce Kellett <[email protected]
> wrote:
On 8/09/2015 4:56 pm, Stathis Papaioannou wrote:
I will ask you the same question as I did Brent: do you
conclude from the fact that when you toss a coin it comes up
either as head or tails that the world does not split into
two parallel versions of you, one of which sees heads and the
other tails?
I would conclude that a coin toss does not provide any
evidence for multiple worlds or a split. The only evidence we
have from this data is that the outcome of the toss is
uncertain. There is no evidence there for any split of anything.
It is not evidence FOR a split but is it evidence AGAINST a
split?
It is evidence that the assumption of a split is not necessary
in order to understand everyday happenings. So, by the
application of Occam's Razor, no split happens.
So you agree that we would still observe the probabilities we
do if we lived in a deterministic world in whaich all
possibilities are realised?
No, because not all possibilities happen in this world. If all
possibilities were
realized
in
this world, then there would be no uncertainty, no
probabilities. Possibility and actuality would be the same
thing. All the horses would win the Melbourne cup; and we don't
live in such a world.
Obviously, not all possibilities happen in this world, but they
might happen in parallel worlds that don't interact with each
other. The argument is that probabilities emerge from this,
since you don't know which world you will find yourself in. You
bet on the favourite in the race because you think you are more
likely to end up in a world in which the favourite wins.
In other words, probabilities can make perfect sense in a single
deterministic world. This was understood a long time ago with the
development of statistical mechanics. The idea that "all
possibilities happen in parallel worlds" does not actually make a
lot of sense. There is no current physical theory that implies
this (without the addition of a lot of unevidenced assumptions).
So probabilities do not emerge from this, they come from quite
simple assumptions of randomness and ignorance.
Probability in the MWI of quantum mechanics is problematic.
Regardless of claims to be able to derive the Born Rule in
Everettian models, all attempts fail because they are circular --
they need the Born rule in order to have non-interacting worlds,
so you cannot then use these independent worlds to derive the
Born rule. Gleason's theorem is no help -- it suffers from all
the same problems as the Deutsch-Wallace approach.
You don't seem to be disputing that we would still experience a
probabilistic world even if all possibilities were actually
realised, even though you do dispute that we in fact live in such
a world.
I'm not sure if you are disputing that, to give a simple model
case, if a coin was tossed and the world split in two, with one
version of you seeing heads and the other tails, the probability
of each outcome is 1/2.
Whether or not all possibilities are realized, they are not in
evidence, so their relevance to the question of probabilities is
questionable.
Your simple model case of a coin toss causing a world split is
just a made-up example to give the result you want, so again its
relevance is dubious. There is no sensible physical theory in
which the world splits on classical coin tosses.
If you can't imagine a world split, consider a virtual reality in
which the program forks every time a coin is tossed, one fork
seeing heads and the other tails. You are an observer in this
world and you have this information, so you know for certain that
"all possibilities are realised" when the coin is tossed. What
would you say about your expectation of seeing heads?
I presume you mean that the world is duplicated on each toss, with
one branch showing each outcome. We are back to the dreaded "person
duplication" problem. My opinion on this is that on such a
duplication, two new persons are created, so the probability that
the original person will see either heads or tails is precisely
zero, because that person no longer exists after the duplication.
So if some aliens create a copy of you in Andromeda, then you cease
to exist as a person?
Note: according to current comological models, space is infinite
and uniform, which means infinite copies of you exist (though very
far away).
Not if spacetime is a continuum - and there's evidence that it is.
Why would spacetime being a continuum preclude duplication in an
infinite universe?
Indeed that would not be sufficient, but it is *necessary* if you want
still identify yourself with a "unique real 3p describable thing". It
has to be continuous, and actually transfinite, non #-computable, with
# for transfinite generalisation of the notion of computable.
Oracles and "super-Turingness" cannot help, as the UD dovetails on
them too, there is a need of an axiom of infinity, and what I like in
computationalism, is that we don't need axiom of infinity in the
starting (primitive) assumptions (then we can explain why axiom of
infinities can make machines more competent to solve the problem they
are necessarily confronted too).
With digital mechanism, unique are we not. We are only locally
relatively unique, but strictly speaking we are types, not token. Comp
is many types no token. Token are indexical "illusions".
Bruno
--
Stathis Papaioannou
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