On 8/09/2015 10:57 pm, Quentin Anciaux wrote:
2015-09-08 14:11 GMT+02:00 Bruce Kellett <[email protected]
<mailto:[email protected]>>:
On 8/09/2015 9:14 pm, Stathis Papaioannou wrote:
On 8 September 2015 at 20:48, Bruce Kellett
<[email protected] <mailto:[email protected]>> wrote:
On 8/09/2015 8:40 pm, Stathis Papaioannou wrote:
On 8 September 2015 at 17:39, Bruce Kellett
<[email protected]
<mailto:[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.
Either MWI is true, and all possibilities happen or it is not... so
the questions is, do you think that MWI is false, because
probabilities seems to means something in this world... because what I
understand of what you're saying, is that if MWI is true then
probabilities should have no meaning, but as you say they have
meaning, then MWI is false... Is that what you're implying ?
This is too imprecise. Even given MWI, not all possibilities happen.
only some range of possibilities given by the basis states of the
measured wave function. So, even in MWI, not all horses win the
Melbourne cup in some world or the other. Coin tosses and horse races
are classical happenings in a classical world, and MWI has very little
relevance to discussions of probability in these cases. Classical
uncertainty and probability are simply the results of ignorance of
sufficient detail about the initial conditions. There is, therefore,
absolutely no incompatibility between determinism and the usefulness of
probabilistic notions.
Such considerations are merely clouded by appeals to quantum mechanics
and MWI. There is absolutely no physical evidence for MWI -- it is an
interpretation of a theory, not a theory in itself. Probabilities in MWI
are problematic, just as MWI itself is problematic because it is not
sufficiently well-defined. There is no clear criterion for what counts
as a world in this approach (and, as Brent says, no measure over the
possible outcomes) -- various people just make up their own ideas as
they go along. No one has had a revelation written on the tablets of
stone as to what is the 'correct' interpretation of Everettian worlds --
there is no concrete evidence one way or the other. And without
evidence, you are doing metaphysics, not physics in the real world.
Bruce
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.
