On 5/12/2010 9:48 PM, Rex Allen wrote:
On Tue, May 11, 2010 at 10:29 PM, Brent Meeker<meeke...@dslextreme.com>  wrote:
I'm confused about your theory of this, Rex.  You talk about "honest" vs
"dishonest:" universes and how the initial conditions must determine what
theories we have about the universe
This point about initial conditions and causal laws "determining" what
follows, including our discovery of various theories, is reasonable
isn't it?

IF you assume a physicalist view of reality, of course.


and since there are a lot more dishonest
ones than honest (a point not in evidence) we have no reason to believe our
theories of the universe.
So the "no miracles" part of my title is a reference to Hilary
Putnam's observation:

“The positive argument for realism is that it is the only philosophy
that doesn't make the success of science a miracle”

This is discussed here:  http://plato.stanford.edu/entries/structural-realism/


As to my statement that "It seems to me that this set of deceptive
universes is likely much larger than the set of honest universes", my
reasoning is:

1)  If we assume physicalism/materialism

2)  and if we assume that a computer simulation of a brain+environment
would give rise to the same conscious experience as a real brain in a
real environment (i.e. multiple realizability)

3)  Next, we know that there are infinitely many different Turing
machines capable of running any given computer simulation.

4) We can therefore conceive of a universe containing nothing but an
implementation of such a Turing machine.

5) And we can therefore conceive of infinitely many universes, each
containing a different Turing machine that runs the same "brain
simulation" program.

6) Therefore it's conceivable that there could be infinitely many of
these deceptive universes running "Matrix"-style simulations of *any*
"honest" universe.


So how many honest universes can there be that will "honestly"
generate our conscious experiences?  I would think that the more
accurate our observations become, the fewer universes there are that
can honestly generate them...

With maximumly accurate observations, then only 1 universe (and it's
exact duplicates) could honestly generate those observations.  Though
maybe we get into quantum uncertainty issues here.



But then you cite Schulze and Kant who contend
that you have no reason to think there is a universe or causal laws or
anything except your cognitions.
Well, Kant contended that we had good reason to believe that a
noumenal world existed...but that we couldn't know anything about it
beyond the fact of it's existence.  He explicitly addressed this in
the "Refutation of Idealism" which he added to the second edition of A
Critique of Pure Reason (1787) to avoid the charge that his
Transcendental Idealism was just a variation of Berkeleyan Idealism.

Schulze basically showed that Kant's arguments against Cartesian
Doubt, Berkeleyan Idealism, and Humean Skepticism didn't go through.
According to Schulze, Kant's arguments end up strengthening the case
for these views, instead of countering them.

Interestingly, one of the reviewers of Schulze's Aenesidemus was
Johann Fichte (1764-1814), who came to this conclusion:

"Fichte did not endorse Kant's argument for the existence of noumena,
of 'things in themselves', the supra-sensible reality beyond the
categories of human reason. Fichte saw the rigorous and systematic
separation of 'things in themselves' (noumena) and things 'as they
appear to us' (phenomena) as an invitation to skepticism. Rather than
invite such skepticism, Fichte made the radical suggestion that we
should throw out the notion of a noumenal world and instead accept the
fact that consciousness does not have a grounding in a so-called 'real
world'. In fact, Fichte achieved fame for originating the argument
that consciousness is not grounded in anything outside of itself."

So.  There's nothing new under the sun...


You can't draw any conclusions about
probability from that.  Before you can count up the infinite number of
"Matrix" universes and Boltzmann brains, you need to suppose there is
something beyond your own thoughts.
So I guess in the future I need to be more clear about where I'm
assuming physicalism to make arguments against it.  I'm not actually
arguing that "Matrix" universes and Boltzmann brains exist.

I'm saying that IF we assume Physicalism, I don't see how we can rule
out Matrix universes and Boltzmann brains, except by fiat.  They seem
to be "likely" consequences of Physicalist assumptions.  As likely as
the mainstream physicalist conclusions that the world really is
(generally) as it appears to be.

Only because you think cardinality is a measure.

I commented on Sean Carroll's position on "Cognative Instability" in
"The Past Hypothesis" thread.  Cognative instability is only a problem
if you refuse to relinquish the starting assumption that an
independently existing physical world is the cause of our experiences.

But you seem to stop short of the last step. Assume physicalism: this leads to the inference that all the evidence for physicalism and for an external world is unreliable and all perception and thought that seems to refer is unreliable and so your only reliable knowledge is that of ephemeral thoughts that in all probability have no meaning.



And I doubt you've had an infinite
number of thoughts about anything.
If physicalism and eternal recurrence are true, then I've had the same
few thoughts an infinite number of times!  Does that count?


Tangentially:  isn't your claim that you are only interested in theory
to the extent that it is "useful", essentially a skeptical position?


That's not my only interest in theories, but it's one. Why should not "useful" be the measure instead of cardinality - at least it can satisfy Kolmogorov's axioms.

Brent

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