Re: [sl4] The Many Worlds of Hugh Everett

From: John Clark (
Date: Fri Aug 20 2010 - 09:12:26 MDT

On Thu, Aug 19, 2010 at 1:03 AM, Matt Mahoney <> wrote:

"Thanks for the excellent book review."

And thank you for your kind words.

"One point where I disagree with Everett is the need for an uncountable
> infinity of universes rather than a countable infinity."

Everett just couldn't get his theory to work with a countable infinite
number of universes, and as far as I'm aware nobody else has managed to do
it either.

"Everett must have been aware that the observable universe has a finite
> description length (about 10^122 bits)."

I'd take that figure with a grain of salt, it assumes we know what happens
when things get so small they approach the Planck length of 1.6* 10^32
centimeters, and we really don't. We won't be sure about that until we have
a quantum theory of gravity.

And even if that figure is true it wouldn't preclude an infinity of worlds
of whatever cardinality. Some of those other universes would be variations
on this one but others would have no point of correspondence to ours at all
and be completely different, including having a different total information
content, even an infinite information content.

  John K Clark



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