Hi Russell
Thanks for the long exposition. I am not sure I can do
it justice but I will give it a shot...
Godfrey Kurtz
(New Brunswick, NJ)
-----Original Message-----
From: Russell Standish <r.standish.domain.name.hidden>
To: kurtleegod.domain.name.hidden
Cc: marchal.domain.name.hidden; everything-list.domain.name.hidden.com
Sent: Thu, 1 Sep 2005 09:36:08 +1000
Subject: Re: subjective reality
On Wed, Aug 31, 2005 at 09:59:33AM -0400, kurtleegod.domain.name.hidden wrote:
> [GK]
> Now I am confused! So you do not believe Bruno's COMP=YD+CT+AP
> but you still believe it is a good enough approximation of reality to
> "deliver most of physics as we know it today". Are you saying that,
> without assuming COMP you derive all of that physics? I guess I
> will have to read your book but a Yes/No answer would help me
> decide whether I want to read it at all...
>
> I would rather argue out your assumptions because, as you may
> agree, measures of metaphysical extravagance tend to be a bit,
> if I may use the word, subjective. I am much more interested in
> how one can empirically decide whether a metaphysical thesis
> is indeed too extravagant to be true.
>
> Best regards,
>
> -Godfrey
>
[RS]
The Maudlin Olympia/Klara argument (equivalently Marchal's filmed
graph argument) has convinced that the brain is quantum mechanical to
some extent. I am largely unimpressed by the works of others who've
argued this point, however, eg Penrose, Stapp or Lockwood. I'm
sceptical that the brain is a quantum computer. My suspicions, which I
argue in my book, as well as many times on this list, is that a
certain amount indeterminism is exploited, and indeed perhaps required
by consciousness. Thus it would negate the strictest version of YD -
one would not survive with your "brain" replaced by a Turing
machine. However, I do think it is possible to replace one's brain by
a machine of some sort, provided one doesn't restrict it to the Turing
class of machines.
[GK]
Now I find that a much more reasonable position than that of Bruno's
and pretty much akin to my own proclivities on the subject! I too am
not
convinced by Penrose et al. but I have some grounded suspicion that
the brain is not Turing emulable. Even John Searle agrees that the
brain is a machine of some sort, just not a Turing-like machine!
[RS]
How does this affect Bruno's UDA? As far as I can tell, steps 1-6 go
through as before, but after that the conclusions are not so clear.
[GK]
But isn't step 1 the YD?
[RS]
Now as for deriving physics from properties of the observer, what I've
achieved is a derivation of the following quantum mechanical
postulates:
1) That states are vectors in a complex Hilbert space
2) These vectors evolve according to a unitary differential equation
(aka Schrodinger equation)
3) The Born rule
There is usually only one other postulate given in QM, the so called
correspondence principle, which connects the quantum world with the
classical. I have not obtained the correspondence principle, but Vic
Stenger gets most of the way by appeal to gauge invariance.
[GK]
I don't find any of the above (axioms) very hard to derive from
classical local assumptions. Indeed Schrodinger derived his
equations from classical mechanics (plus the de Brogie ansatz).
But this is NOT the whole of quantum mechanics as I am sure
you know. It also does not sound like a one way ticket to a
MW version of QM but it is surely closer than to conventional QM.
[RS]
My assumptions for obtaining these postulates?
1) The "everything" assumption, or that we are seeing a single
possibility from the ensemble of all possibilities. This is roughly
equivalent, I believe to Bruno's Arithmetic Platonism, however
strictly speaking it is identical to assuming the existence of the
output of his universal dovetailer.
2) A uniform measure on the ensemble of possibilities
3) A subjective experience of time. By this, I mean that we perceive
an ordered series of "observer moments" (using the terminology of
this list), or "worlds" to use say Modal logic terminology. Being
ordered, they can be mapped to the real numbers by an order
preserving map, and this defines a unique topology. By fixing the
map (which is arbitrary), one induces a metric upon time, or in
other words defines a clock. This is the physicist's notion of time
- coordinate time and proper time.
4) Our knowledge of the world is updated according to an evolutionary
process. I apply Lewontin's 3 criteria of evolutionary processes,
variation, selection and heritability. Our successor "observer
moment" is selected from the range of possible observer moments
according to a probability distribution, from heritability we get
unitary differential evolution.
[GK]
That sounds quite interesting to me already, if you can do that much,
though I cannot vouch for any of those assumptions (except perhaps 2)
without probing a bit your "everything" and your "observer moments".
(3) sounds quite reasonable and promising and not very different from
recent speculative programs developed by Page and Brandon Carter.
I am not sure about the evolutionary argument but physicists abuse
those quite regularly so I would not blame you.
[RS]
That's about it. I'll let you read the book. Assumption 3) above
(which I call TIME), I believe is derivable from COMP (though not the
converse). Bruno is not sure, and we occasionally argue about
it. However, reading Lockwood's book, I notice that it could also be
called neo-Cartesianism, that is a belief that consciousness is
unified, and has a single stream of consciousness. It is perhaps
somewhat controversial (given that the brain is nothing like that - it
is parallel, distributed and rather "messy"), however Lockwood gives a
spirited defence of this position, and uses it as his cornerstone for
arguing the quantum mechanical nature of the brain. Also Daniel
Dennett argues for a similar point of view, which he uses the label
"Joycean machine". From my point of view, it appears to be necessary
to get the laws of physics as we known them. If there were people
around with a different sort of mind, do they see a different sort of
physics? Lots of questions.
For getting the rest of physics from this program, I can only really
speculate at this stage. We need to know why we live in a 3D world,
once this fact is established, gauge invariance gets us most of the
rest of the way.
Cheers
[GK]
I am not sure I follow you that far. Stenger has some pretty radical
views some of which I share. But last time I checked he embraced
something like the infamous "transactional interpretation" of QM
developed by John Cramer which has some serious problems on
its own. I'll try and get to your book shortly.
Thanks,
Godfrey
--
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Received on Thu Sep 01 2005 - 10:37:21 PDT