Who needs far-out religious myths – walked on water! resurrected from the dead!— when science is able to come up with equally mind-blowing hypotheses that have the advantage of being plausible?
Take the case of Boltzmann brains. These aren't actual brains, but most likely are free-floating conscious entities that pop out of random quantum fluctuations in the vacuum that pervades the universe.
None have been observed. In fact, a New Scientist article on the subject (August 18 issue) says:
A Boltzmann brain is so improbable, in fact, that there is essentially no chance that even a single one has appeared in the 13.7-billion year history of our universe. But factor in the accelerating expansion of the universe, and the picture changes: it points to an infinitely large space that will last an infinitely long time, with ongoing fluctuations in the vacuum.
This will be a cold, dark and inhospitable place for conventional creatures, but a perfect breeding ground for Boltzmann brains, which would see only empty space around them.
Pretty creepy. From our point of view. However, if you're a Boltzmann brain you've just arisen spontaneously out of nothing. No history. No evolution. No words like "creepy" in your consciousness.
So it's impossible to say how a Boltzmann brain would see things. Which is why the New Scientist article has this sub-heading: Cosmologists are afraid – very afraid.
This is what I find most interesting about Boltzmann brains: how they point to the subjectivity of Homo sapien'ish conceptions of the cosmos. This is what scares some scientists, because our understanding of the laws of nature is necessarily founded on how we go about understanding things.
Cosmology, indeed most of science, assumes that we humans are typical observers in the grand scheme of things…So here's the problem: some well-established cosmological models predict that, trillions of years in the future, Boltzmann brains could vastly outnumber "ordinary observers" like us, who depend on aeons of evolution and life support.
If that is true, then over the lifetime of the universe, they – not we – might be the typical ones. That's scary, because models suggest that their view of the cosmos would be strikingly different from ours.
Um, let's see. Would (1) a disembodied consciousness that just sprang into existence from a quantum vacuum fluctuation look upon the universe differently than (2) a human being acculturated by other people, all of whom perceive the world through physical organs? Sure seems so.
Now some people who are skeptical about science likely are going to jump on the Boltzmann brain bandwagon and say, "Told you so! Science is just one way of looking at reality. The so-called 'laws of nature' are just artifacts of human cognition, not how things really are.'"
OK, there's some truth to that.
But to my mind the possibility of Boltzmann brains undercuts a lot more than the scientific method. It demolishes the objectivity of everything – including every defined form of spirituality, religion, and mysticism, which usually are promoted by science skeptics as being more valid ways of knowing.
What I love about Boltzmann brains is how they stretch (or blow to smithereens) our usual assumption that human consciousness is the template for every sort of consciousness. Rather, says the New Scientist article:
What exactly might these things be? In theory, they could take on almost any form, but the larger and more complex they are, the less likely it is that they will appear, according to the laws of probability and quantum mechanics.
They could be disembodied brains with eyeballs, floating in outer space. They could consist of a whole body, encased in a space suit and equipped with an oxygen tank. They could be human brains, animal brains, or an intelligent alien species made of gas.
What matters is that they qualify as conscious – by whatever definition researchers agree on.
Well, if I was a Boltzmann brain I might take issue with that last sentence. Hey, humans! I'll decide whether I'm conscious! Not you. Things look differently out here in the infinite vacuum.
I've enjoyed pondering a cosmos with no consciousness. As well as a cosmos that is only consciousness. Boltzmann brains stimulate the notion of another alternative: a cosmos with a freakingly inconceivably different form of consciousness from ours.
Some attributed quotes:
Physicist Arthur Eddington. "Not only is the universe stranger than we imagine, it is stranger than we can imagine."
Biologist J.B.S. Haldane: "Now my own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose."
Sounds like a blown mind is a lot closer to truth than a certain mind.