From: Hal Finney (hal@finney.org)
Date: Wed Mar 05 2003 - 13:39:05 MST
Lee Corbin writes regarding
http://xxx.lanl.gov/pdf/physics/0302071:
> Thanks a million! This is almost as good as Tegmark's.
Referring to Tegmark's paper about four different ways that "parallel
universes" arise in modern physics,
http://it.arXiv.org/abs/astro-ph/0302131.
> The central, compelling, and overwhelming fact: the theory
> of Inflation, accepted by roughly 95% of cosmologists, calmly
> predicts an infinity of Earths of any given description.
This is only the second of Tegmark's four ways of finding infinite Earths.
The first is simply an infinite universe, the third is the MWI, and the
fourth is the notion that "everything exists" in the Platonic sense,
explored on Wei Dai's everything-list.
> The philosophical implications are simply staggering. No
> longer can I be "The Speaker for the Uninstantiated", as
> I used to aspire. I even must retract "It is our duty to
> rescue as many people from non-existence as possible",
> which I have been claiming for fifteen years!
>
> Why? Very simply because everyone already exists. I had
> been aware that this was an implication of MWI, and Hal
> had even stated as much on this list a few months ago.
> But an *interpretation* of QM, coupled with the "ghostly"
> feel of the Other Worlds, combine to render the existence
> of every possible person and alien moot.
>
> But now, nothing could be more concrete. From the simple
> assumptions of the concordant universe, i.e., the homogeneous
> universe first proclaimed by Saint Bruno in 1600, inflation
> proves universal existence.
Or, if Tegmark's first level works, homogeneity implies universal
existence even without inflation.
> It remains for us only to determine how much run time people
> ---including ourselves---are to get. And of course, any
> answer failing to specify the maximum possible fails to
> attain the highest morality.
Yes, perhaps you can re-style yourself The Speaker for the
Underinstantiated. Rather than rescuing people from non-existence,
you can strive to maximize the total quantity of sentient existence.
One of the paradoxes that I have always struggled with is this: if you
run exactly the same conscious program twice, does it matter? Does it
increase the "measure" or "probability" of that conscious experience?
Do I do good by re-running someone's pleasant experience, and harm by
re-running a bad one?
The reason it's a paradox is because re-runs are particularly prone to
philosophical slippery-slope arguments where we blur the lines between an
"actual" re-run and what amounts to a picture of one. I won't recap the
arguments here, they have been discussed ad infinitum in the archives.
The point is that only re-runs are succeptible to these arguments;
fresh runs doing novel calculations cannot be replaced by pictures of
themselves because the pictures won't exist until the calculation is done.
This has led me to consider the possibility that re-runs don't count,
that they carry no experiential (and therefore moral) weight.
However, the notion of many-worlds at Tegmark's level 1 and 2 suggests
that we do have to consider identical universes to add to the measure
and probability of the experiences they contain. We have all these
identical Earths, and for probability to work right we need to assume
that the total probability for a given experience is proportional to
the fraction of Earths where that experience happens, even though many
of them will be identical. Therefore identical calculations must be
counted and added separately in considering their contribution to the
overall probabilities of experience.
I will have to give more thought to the paradoxes of instantiation of
repeated experience, to see if these simpler and more concrete levels
of parallel universes can shed any light on the problem.
Hal
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