While QM on its own (i.e. Everett) predicts that there is no collapse threshold - that
if you can keep a system from decohering, it will remain in a superposition regardless
of how large it is.
So at some point QM+Collapse has to come up with a mechanism for collapse, and at that
point it becomes testable, at least in theory (depending on our level of technology, I
mean).
On 10 March 2014 13:17, chris peck <[email protected]
<mailto:[email protected]>> wrote:
Hi Bruno
*
>> With respect to the UDA, graves and me are just using different
vocabulary.
Really?
the last time I quoted her:
"/What ... should Alice expect to see? Here I invoke the following
premise:
whatever she knows she will see, she should expect (with certainty!) to
see. So, she
should (with certainty) expect to see spin-up, and she should (with
certainty)
expect to see spin-down./"
But that can only be a 3-1 description. She handles the 1p by a
maximization of the
interests of the copies, and that is equivalent with the FPI, without
naming it.*
Funnily enough Bruno, if I was opportunistic I would just about accept
that. I mean
personally, I would argue that the vocabulary used is identical between you
and
Greaves and she explicitly denies your probability distribution from the
first
person perspective. But a bigger problem for you raises its head if I put
that to
one side.
if, as you claim, there is no substantive difference between your theory and
Greaves' just because she has some other mechanism of deriving the bare
quantities
you want, then you may as well say that there is only a difference in
terminology
between your theory and any other interpretation of QM. After all they all
deliver
0.5 by some now irrelevant metric too. You've just relugated your theory to
the
purely metaphysical. You're tacitly admitting that all these theories are
just
re-skins of the same underlying engine with bugger all to choose between
them.
In a way that is something that I have felt for a while. Everettian QM does
not
improve upon QM + collapse in the way say relativity improves on Newtonian
physics.
There is no concomitant improvement in predictive capability on offer. Its
a purely
theoretical change intended to smooth out conceptual difficulties but it
can only do
that by delivering further difficulties of its own. All your theories are
scientifically irrelevant.
------------------------------------------------------------------------------------------
Date: Sun, 9 Mar 2014 11:32:08 -0700
From: [email protected] <mailto:[email protected]>
To: [email protected]
<mailto:[email protected]>
Subject: Re: Tegmark and UDA step 3
On 3/9/2014 12:47 AM, Bruno Marchal wrote:
On 08 Mar 2014, at 06:16, meekerdb wrote:
On 3/7/2014 8:26 PM, LizR wrote:
On 8 March 2014 08:14, meekerdb <[email protected]
<mailto:[email protected]>> wrote:
On 3/7/2014 1:24 AM, LizR wrote:
On 7 March 2014 18:29, meekerdb <[email protected]
<mailto:[email protected]>> wrote:
On 3/6/2014 9:15 PM, Jason Resch wrote:
A related question is, is there any such thing
as true
randomness at all? Or is every case of true
randomness
an instance of FPI?
*Or is FPI just a convoluted way to pretend there
isn't true
randomness?
*
If one assumes QM and the MWI are correct then it isn't
pretending,
True; but I don't assume that.
Since your original statement above only makes sense in some
context -
which you haven't revealed, as far as I can tell - perhaps you
could
tell us what you /are/ assuming?
I'm not assuming anything, I'm just pointing out that one could
assume
something different than QM and MWI. For instance, start with MWI
but then
suppose that at each "branching" only one instance of you continues.
Doesn't that accord with all experience?
Like Ptolemeaus epicycles. The point is to accord with the simplest
theories we
have for most if not all experiences, like QM, or computationalism.
At each "branching" only one instance of you continue, you say, but
that does
not accord well with the simplest explanation of the two slits
experience. You
will have to explain why the superpositions act in the micro and not
the macro,
and this needs big changes in QM (= SWE), or even bigger to
computationalism.
But you have to explain this anyway; except the question is transformed
into why do
I only experience one reality. Presumably the answer is in decoherence and
the
off-diagonal terms of the density matrix becoming very small (or maybe even zero).
Once you have this answer then you can look at the density matrix, as Omnes does,
and say, "QM is a probabilistic theory, so it predicts probabilities. What
did you
expect?"
My point is that these sharp questions are asked of QM because it is a
mature theory
with lots of very accurate predictions, but "comp" as a new speculative
theory kind
of gets a free ride on the very same questions, e.g. why do we not
experience
superpositions? Why isn't there a superposition of the M-guy and the W-guy
according to comp. How can consciousness be instantiated by physical processes?
Most people on this list just assume it can't and dismiss the very idea as mere
physicalism. But they don't ask how can consciousness be instantiated by
infinite
threads of computation - that's mysterious and consciousness is mysterious,
so it's OK.
If not, you can always consistently assume everything is done by a God
to fit
your favorite philosophical expectations. You can do that, *logically*,
but this
is no more truth research, but wishful thinking.
But you know that is not what is done. QM predicts probability
distributions that
are confirmed to many decimal places. QFT predicts some measured values to
11
decimal places. And you rely on QM to explain the world in in you theory of comp.
Your approach is to explain QM and then let QM do the rest of the work - which is
fine. But my point is that QM can still do the work even if it's a
probabilistic
theory. So unless comp can make some better predictions than comp it's
just an
interpretation and it's trading off a distaste for randomness (a very
restricted and
well defined randomness) for a love of everythingism. Which is why I hope
comp can
predict something about consciousness; where it may offer something beyond
just
interpretation.
Brent
Bruno
http://iridia.ulb.ac.be/~marchal/ <http://iridia.ulb.ac.be/%7Emarchal/>
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