[extropy-chat] Boltzmann Brains

Amara Graps amara at amara.com
Wed Feb 21 09:39:12 UTC 2007

Curious about Boltzmann Brains?


{begin quote from the blog}

Then, though, there are the BB's in the universe: Boltzmann Brains.
Random fluctuations of the fabric of spacetime itself which, most of the
time, are rather insignificant puffs which evaporate immediately. But
sometimes they stick around. More rarely, they are complex. Sometimes
(very very rarely) they are really quite as complex as us human types.
(Actually, "very very rarely" does not quite convey just how rare we are
talking now.) And sometimes these vacuum quantum fluctuations attain the
status of actual observers in the world. But, the rarest of them all,
the BB's, are able to (however briefly) make actual observations in the
universe which are, in fact, "not erroneous" as Don Page put it.

The man was a compelling speaker, and soon I realized there was an
actual intellectual debate underway in the high end of the
cosmology/high energy community as to what the role of these BB's might
be in the universe, in the very far (or maybe not so far) future. We
have a certain prejudice that, well, there just aren't so many of them
out there at this stage of the game, 14 billion years after the Big
Bang. We'd like to think that we have the stage at the moment, we OO's,
um, assuming there are in fact more of us out there. (Any other
non-human OO's out there, could you let us know, please that you are
listening? We have a few questions for youŠ)

The thing is, when you start talking about very veryŠvery rare things
like Boltzmann Brains, you are talking about REALLY long times. Much
longer than we've had on earth (and I mean 4.5 billion years) by many
orders of magnitude. Numbers like 10 to the 60th years were being batted
around like it was next week in this talk. By those times, all the stars
and all the galaxies have gone out, and gone cold, and space has
continued to expand exponentially and things are long past looking
pretty bleak for the OO's still around, who (we presume) need heat and
light and at least a little energy of some sort to survive, even if we
are talking about very slow machine intelligence (even slower than
humans for example).

So eventually, the mere fact that there is, at these long times, just
oodles of space in the universe means that the BB's become more and more
common (even if they are rare) and eventually dominate the, uh,
intellectual landscape of the universe. Of course this immediately
raises all sorts of questions, such as mind/matter duality, the nature
of reality and consciousness and multiple consciousnesses, perceived
versus objective independent reality. Not to mention whether our
"universe" is the only one. Okay, I'll stop nowŠ

Well, at this point in the talk, being new to this and my mind already
quite blown,

{end quote from the blog}


Amara Graps, PhD      www.amara.com
INAF Istituto di Fisica dello Spazio Interplanetario (IFSI), Roma, ITALIA
Associate Research Scientist, Planetary Science Institute (PSI), Tucson

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