On 30/11/2017 5:53 am, Brent Meeker wrote:
On 11/28/2017 11:10 PM, Bruce Kellett wrote:
On 29/11/2017 5:28 pm, Brent Meeker wrote:
On 11/28/2017 8:51 PM, Bruce Kellett wrote:
On 29/11/2017 3:22 pm, Brent Meeker wrote:
On 11/28/2017 7:59 PM, Bruce Kellett wrote:
On 29/11/2017 2:29 pm, John Clark wrote:
On Tue, Nov 28, 2017 at 9:05 PM, Brent Meeker
<[email protected]>wrote:
>>
And how is the Eternal Inflation Multiverse
fundamentally different from the String Theory Multiverse?
>
I didn't say they were different from each other; I said
they were different from the mulitple worlds of Everett
which all share the same physics with the same physical
constant values.
I see no reason all the Everett worlds have the same physics,
Everettian worlds follow from assuming that the Schrödinger
equation applies everywhere without exception, so that all
physical evolution is unitary. A change in the underlying physics
-- such as a change in the value of fundamental constants,
Planck's constant or Newton's constant for example -- would not
be unitary, so cannot occur in MWI.
The same reasoning applies to the Level I multiverse from eternal
inflation -- same physics everywhere. However, the level ii
multiverse from the string theory landscape has physical
constants and the number of space-time dimensions varying from
world to world.
unless it turns out that only one sort of physics can happen.
But lets assume you're right, then the string theory multiverse
must be larger than the many worlds multiverse incorporating
everything in Everett's version and MORE; after all if it
contains universes with radically different laws of physics it
must also contain more modest things like a world where my coin
came up heads instead of tails.
I would suggest that there is no such world. Whether a coin comes
up head or tails on a simple toss is not a quantum event; it is
determined by quite classical laws of physics governing initial
conditions, air currents and the like.
That's not so clear: https://arxiv.org/abs/1212.0953v1
I don't find the arguments in this paper in the least convincing:
air current easily overwhelm Brownian motions, and quantum
uncertainties in times of neural firings are not responsible for
the results of coin tosses, or random digits of pi. We can
construct classical coin tossers, etc. It sounds like they are very
close to superdeterminism.
Well I'm pretty sure they're wrong about the coin flipping since
Persis Diaconis trained himself (as magicians do) to flip a coin and
catch it so consistently he can make it heads or tails at will.
Actually, the whole idea that quantum effects in the brain affect
behavioural outcomes is pretty nonsensical. As we know, the brain is
a hot system with decoherence times of the order of nanoseconds. If
random quantum effects affected behaviour, behaviour would be random
and purposeful action would be impossible.
But some randomness is useful and evolution would not try to drive it
to zero (c.f. Buridan's ass), which is not to say it needs quantum
randomness. There are plenty of of sources of randomness in the
environment.
As you say, not all randomness is quantum randomness.
This is ruled out by experience -- as is the related notion of
superdeterminism.
I don't see that superdeterminism is ruled out, or can be ruled out by
experience. Experience would seem to rule out MWI too, because like
superdeterminism it posits stuff that can't be experienced:
superdeterminism because the don't happen, MWI because they happen in
another "world" to a different "you".
Maybe that is a good reason to disregard such ideas as pure fantasy. The
problem with superdeterminism, as outlined by Tim Maudlin, is that is
would render science and the endeavour to understand the nature and
operation of the world futile -- nothing could ever be tested because
there could be a giant conspiracy to deceive us.
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 https://groups.google.com/group/everything-list.
For more options, visit https://groups.google.com/d/optout.
