Boltzmann brains

[unixronin]

New Scientist for August 18-24 contains an article talking about Boltzmann brains and the nature of the Universe.  (The concept of the Boltzmann brain is basically this:  We know elementary particles are constantly popping in and out of existence from quantum vacuum fluctuations.  Occasionally, entire atoms pop into existence in this way.  The more complex a construct, the lower the probability of its spontaneous appearance.  Theoretically, given a sufficiently large space and a sufficiently long time, quantum fluctuations should cause complete functioning consciousnesses able to observe the Universe to spontaneously pop into being.)  Much of the thread of the article seems to center around discussion of how crucial it is that Boltzmann brains never outnumber physical human observers, because if that happened we wouldn't be typical of the Universe, and everything we know might go poof.

Oh, boy.  There's that old anthropic bugbear raising its head again.  Let us suppose that tomorrow, some theorist irrefutably proves that, 10^{10^30} years from now, Boltzmann brains will dominate the Universe.  Would his proof cause the universe as we know it to suddenly disappear in a flash of logic?  I rather doubt it.  (In fact, were we able to somehow prove that Boltzmann brains becoming the majority obeservers of the Universe would cause the end of existence as we know it, it would logically follow that, at least for now, such quantum observers do not outnumber us.)  Does it even MATTER whether we are typical observers of the Universe, or whether our little corner of it is typical?  Again, I rather doubt it.  Nothing that happens to the Universe in the deep future can possibly affect the demonstrable fact that right now, we and our little hospitable corner of the Universe exist.

I propose that we will never fully understand the Universe, so long as our theories about the nature of the Universe are unconsciously built atop a foundation that says it is necessary we remain somehow significant to the Universe, even if only by virtue of being a typically representative sample of it.  I roll to disbelieve that the Universe as a whole gives a blind tinker's damn (figuratively speaking, of course) whether we exist or not.

This, I think, is modern science's version of arguing about how many angels can dance on the head of a pin.

Comments

[unixronin.livejournal.com]

Personally, I think even assumption #1 is highly suspect in itself. I think the whole idea that we have to be somehow significant in the universe is a kind of cosmic tunnel vision. We may have abandoned first the geocentric universe, then the heliocentric one, but it seems we still simply cannot conceive of the idea of a cosmos to which our existence is utterly irrelevant. We seem to have a psychological need to believe that somehow, it matters to the universe that we're here. Isn't it enough that we are here?

As you point out, there are many maybe's involved in the entire chain of reasoning, and considering that the probable timeframe for the appearance of significant numbers of Boltzmann brains exceeds the believed lifetime of the universe so far by more orders of magnitude than there are believed to be elementary particles in the universe, I find it pretty hard to get excited about the possibility. And let's face it - by that time, the universe WILL BE radically different anyway according to current theories, because all baryonic matter will have long, long, LONG since decayed.

There's a word for this type of speculation, but I can't quite bring it to mind. Not sophistry, not solipsism ... but something akin to those.