Originally posted in August 2007.
There was a New Scientist feature last week on Boltzmann Brains. Now I hadn’t heard of these before, and so I thought it may be worth a blog post. A Blotzmann Brain is an intelligent, self-aware entity which arises as the result of a random fluctuation in the entropy of the universe.
I have put this post back on the front page for a while as it has generated some comments since the New York Times ran an article on the same topic (Link)
Lugwig Boltzmann suggested, by invoking the anthropic principle, that we are all here thanks to an extremely unlikely low-entropy fluctuation. If you consider the notion of a virtually infinite inflationary universe then such an organised blip is not only possible but eventually inevitable.
This leads to an interesting conclusion. Our planet sits here with myriad trillions of extremely organised organic beings, not to mention billions of intelligent human brains (mostly). If we can exist here, representing a very high order system indeed, then any lower order systems must also exist in greater numbers. An example of a lower order system would be a Boltzmann Brain, simply a conscious being floating in the universe, able to know what it is.
So are we in fact outnumbered in this universe of ours by Boltzmann Brains? If so then Cosmology is heading for trouble. Much of cosmology is based on the idea that we are typical observers in a typical part of the universe. If the Boltzmann Brains are sitting out there in their trillions, all over the dark void of empty space then we are not typical, they are. Does this change the nature of cosmology, or of the nature of the universe as we understand it.
Let me add one final odd point to this peculiar topic. It is far more likely that rather than a solar system and a planet on which sit six billion individual, intelligent brains, the universe would actually create a singular brain pre-programmed with false memories and experiences, unaware of its true nature as giant floating head. So maybe our individual experience is not so different to that of a Boltzmann Brain after all.
September 4th, 2007 at 1:25 am
There is evidendce that the observed complexity we now perceive is the result of applying an iterative process with simple rules, from exceedingly simple beginnings - and this would trump even the above scenario in complexity and probability of occurrence.
January 19th, 2008 at 11:29 pm
I’m not a scientist, merely a curious layperson who first became aware of the Boltzmann brain theory through an article recently read in New Scientist. Since then I’ve become intriged with this theory. Reading a few blogs on this idea, I keep coming across the theory of a “singular brain pre-programmed with false memories and experiences unaware of its true nature as giant floating head” (as quoted from this blog). I would like to take this a step further and ask all those physicists out there some of the following questions: Why would “a singular brain” which the universe created have FALSE memories? What would lead to that theoraetical conclusion? Why would a singular Boltzmann brain be “unaware of its true nature”? Would the “false memories” be anthropromorphic in nature, or would they be “mirror” memories of possibilities from a divergent universe? Why does this theory assign human psychological needs (the essence of memory & experience) to a singular Boltzmann brain? Why can’t self-awareness exist merely as being “the one” different from “the other ” or surroundings? Furthermore, where does the “hard science” depart form the merely “philosphical” in the Boltzmann brain theory?? I would like to delve further into this mystery. Plesse suggest additional readings. I would greatly appreciate a response, either way. Thank you, SJSTARKMA@msn.com
January 19th, 2008 at 11:40 pm
Is it possible that the “false memory” comes from a backwards relction on a state of high entropy from which our universe is a low entropy fluctuation? SJSTARKMA@msn.com
January 19th, 2008 at 11:41 pm
the word is backwards “reflection”