Sean Carroll and Boltzmann Brain


Sean Carroll wrote a very interesting article on Cosmology and the Boltzmann Brain.


Of course, every issue can have many different points of view. One old grandmother who is the expert of *daily* phenomena sees this Boltzmann monkey Brain issue with a very different view, from her “bathtub dirt-pattern model”.


When the body dirt was washed into the bath water, it does not settle on the bottom of the tub uniformly but with some stringy patterns with both closed (water not drain) and opened (water drained) situations. She thus made a “bathtub dirt-pattern model”.

a. The dirt distribution in the tub water is totally uniform (random or symmetric).

 b. When two dirt particles collide, they stick together (an interaction).

 c. When first two dirt particles collide, the *total* randomness is no more (symmetry-breaking).

 d. This symmetry-breaking accelerates the further randomness-reduction (pattern [or order] forms).


She quickly formulates a “Randomness dynamics” —- when the members in a *totally* random system has an *interaction* (of any kind), it (the interaction) will spontaneously break the *totality* of that randomness, and some patterns (or orders) will be formed.


On the other hand, the “Act I of Hamlet” emergence from the Boltzmann monkey Brain is a result of totally random chance, not a result of the Randomness Dynamics. Thus, the “Act I of Hamlet” in the Boltzmann monkey universe is dead, without a life.


Sean Carroll wrote, “In other words, a universe with a cosmological constant is like a box of gas (the size of the horizon) which lasts forever with a fixed temperature. Which means there are random fluctuations. If we wait long enough, some region of the universe will fluctuate into absolutely any configuration of matter compatible with the local laws of physics. Atoms, viruses, people, dragons, what have you. … And, let’s admit it, the very idea of orderly configurations of matter spontaneously fluctuating out of chaos sounds a bit loopy, as critics have noted. But everything I’ve just said is based on physics we think we understand: quantum field theory, general relativity, and the cosmological constant. This is the real world, baby.”


Again, those atoms, viruses spontaneously fluctuating out of a box of chaotic gas in the manner of Boltzmann monkey Brain are also lifeless and meaningless for this old grandmother. That is, the Boltzmann monkey Brain cannot be a part of the reality. Yet, as long as there is an interaction of any kind among the members of that box, the patterns and orders will emergent, not by any random chance but by the randomness breaking.


But by all means, ΛCDM (“Λ” stands for the cosmological constant and “CDM” for Cold Dark Matter) is wrong.


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3 thoughts on “Sean Carroll and Boltzmann Brain

  1. I became very interested about this theorem. I call it randomness and the formulation of the complexity. Indeed, I read about biology and specifically about specific areas in biology. For example, how natural selection happens and how nature encourages certain choices that’s by bias selection. Therefore, randomness is not impossible in creating a complex creature, but the possibility is too low, if the possibility is near the zero, it’s certainly not zero. However, if complexity were to be created in accordance to Boltzmann’s theory, I would say it wouldn’t be the normal brain that resides under our skull which requires a tremendous amount of oxygen. The probability that there’s another universes isn’t impossible, and perhaps those universes and including our universe is nothing, but a chaotic fluctuation of particles that occurred in billions of billions of years. The hypothetical monkey experiment for for instance, has the possibility of producing Hamlet, that’s not improbable, however, it takes time, it could be even infinite. But Boltzmann Brain seems like science fiction, because we know the brain as we know it, the brain the requires oxygen is linked to other organs in the body. I think brain isn’t a very precise word, probably consciousness is the result of arbitrary universal fluctuation. However, that statement itself cannot be tested in the lab to make it scientific.

    I look back to hear from you

    • Mansoor.
      Thanks for the comment.

      Boltzmann Brain is a total bullcrap not because that it might have a non-zero probability but because there is a right pathway for the coming of this physics universe and of this life universe.
      First, multiverse is a total nonsense, see and .
      Second, this universe carries Turing computer, capable of managing information intelligently, see .
      Third, this life universe evolves intelligently, see .

      • Thanks for the valuable resources. I promise to delve into theses resources details. It’s already late night here.

        I’d like to add one more thing about Boltzmann Brain. It’s true that water can turn to ice if we observe it for a quite long time. As you know there’s no physical law that prohibits that from happening. However, as you just said it’s not about the probability of that event to occur, but the interpretation of the world in such a way is naive. The idea is basically about randomness. The idea of Boltzmann Brain is centered around the principle of (complete and infinite randomness) which is quite the opposite to what we see in our natural world, especially in the evolutionary process, the formation of the DNA for example or how genes and certain traits are selected in organism not arbitrary (randomly), but through calculation. We’re all familiar with the monkey and typewriter experiment, which somehow illustrated the point here. But I really loved the idea of the Weasel program that was written by Dr. Richard Dawkins. I’m aware of its flaws, but I think it’s sufficient to illustrate the natural process (with other things being held constant). Of course, things in the natural world are quite perplexing to the primitive human brain and there always going to be why after we solve a previous question. But logically speaking, if the formulation of the matter or the non-matter around us is simply nothing, but a process of fluctuation involved with particles or atoms, then we must certainly be able to observe that in this giant universe. Probably, we would see more of creepy creatures than a conscious brain or sentient being! Who knows?

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