Boltzmann Brains — 2. Solipsism in a Lonely Cosmos
Les nouvelles idées sur la structure du système nerveux : chez l'homme et chez les vertébrés, 1894. Santiago Ramon y Cajal's.
Irà Sheptûn July 11, 2024
‘Our life is shaped by our mind; we become what we think’.
- The Dhammapada, Twin Verses
In Boltzmann Brains Part 1, we defined entropy as a measure of the number of ways you can arrange a system without changing its overall state. The more arrangements there are for a system, the higher the entropy, and by association the system is considered to be more disordered. We discovered that if we were to have some low entropy state, we would have to assume it came from a higher entropy state by fluctuation and will return to maximal entropy over time, as the Second Law of Thermodynamics tells us. One might interpret from this that entropy has a kind of ‘direction’; what we call the Thermodynamic Arrow of Time. In his renowned lecture series, Physicist R. Feynman writes: “For some reason, the universe at one time had a very low entropy for its energy content, and since then the entropy has increased. So that is the way toward the future. That is the origin of all irreversibility, that is what makes the processes of growth and decay, that makes us remember the past and not the future, remember the things which are closer to that moment in history of the universe when the order was higher than now, and why we are not able to remember things where the disorder is higher than now, which we call the future.”
Władysław T. Benda, c.1918.
So what if this low entropy state was a whole world - a Boltzmann Universe, arising as a fluctuation from an ancient ‘dead cosmos’ of maximal entropy? What are the chances that we exist in such a world? Astronomer A. Eddington dismissed this possibility, positing that if random fluctuations from higher entropies are the sole driver of creation, then it’s statistically more probable that intelligent observers such as you or I will randomly fluctuate into existence than for an entire complex world to emerge with intelligent observers in it!
Going one step further, physicists Albrecht and Sorbo toyed with the irrationality of cosmological theories based solely on a statistical argument.They argued that if we accept that large ‘world-like’ fluctuations are exponentially more improbable than smaller fluctuations from maximal entropy, then these smaller fluctuations will occur much more frequently. Following Eddingtons ideas to their logical extremum, their theory predicts any intelligent observer, equipped with a consciousness to justify their own reality, is likely to be one such example of a smaller fluctuation. What constitutes an intelligent observer in this case? Well plausibly, such a being would only need only the very basic anatomies that are essential to cognition and conscious thought – disembodied brains suspended in a dead vacuum complete with a set of false memories of an artificial life. A Boltzmann Brain. All thoughts both complete and distant in these brains are a by-product of the same statistical improbabilities.
“Perhaps everything we understand about the laws of physics, and the cosmological model we have constructed that predicts we are Boltzmann Observers, are also random fluctuations in our minds. Indeed, there is no reason to trust that our own knowledge of present and past is accurate, or that we have even correctly deduced the nature of this cosmological model up to this point.”
The absurdity of a Boltzmann Brain does raise a very interesting cosmological conundrum – is it more probabilistically likely that all the particles that make up an infinite cosmos somehow converge to form new worlds, or a small local group of high energy particles collide in a vacuum spontaneously to create a sentient brain that begins to dream, if only for a brief time? This is an example of reductio ad absurdum, highlighted by Eddington, and often used in cosmology to test scientific theories. It serves to remind us that we cannot forsake the physics in favor of any other kind of argument, statistical or otherwise, no matter how appealing. It’s a little bit like the monkeys on typewriters scenario – it’s far more likely for a hardworking team of monkeys, bashing at random keys on their typewriters, to randomly type up The Hobbit in its entirety than all the complete works in the Library of Congress.
On a Distinct Form of Transient Hemiopsia, 1873. Hubert Airy.
In the same manner of speaking, it’s far more likely that you are a Boltzmann Brain, and not some happy by-product of an incredibly rare and convoluted aging universe full of unresolved energy in all its improbability! That everything held in your memory and construction of reality; from your first kiss to the French Revolution to the invention of radar, was weaved together by your isolated dreaming mind from the same statistical fluke that brought you into creation. Before you get too worried, one should note the high entropy universe that Boltzmann postulated from statistical thermodynamics looks very different from the relatively ordered cosmos that we actually do observe. Many examples of low-entropy states are seen to emerge naturally. Later theories in modern physics suggest a finite past; ordered states hold memory of conditions when things first started. However, the concept of Boltzmann Brains has continued to be compelling in cosmology, as it cannot be so easily ruled out.
While we might know in ourselves that we are not disembodied brains floating in a dead vacuum, we cannot claim that we and our environment haven’t fluctuated into existence from maximal entropy equilibrium, as an example of a more ordered state. Rather, we are Boltzmann Observers born from an ancient, randomly fluctuating chaotic universe. Perhaps everything we understand about the laws of physics, and the cosmological model we have constructed that predicts we are Boltzmann Observers, are also random fluctuations in our minds. Indeed, there is no reason to trust that our own knowledge of present and past is accurate, or that we have even correctly deduced the nature of this cosmological model up to this point. How do we move past this disturbing theory? How can we reconcile our entire lived experience as a fabricated one beyond the certainty of our own consciousness?
“If I am the only being in the cosmos, who I am is also you as the only being in the cosmos. Your thoughts are transient properties that hold no true essence in their universality – I too experience them.”
These ideas, initially inspired by Eddington’s deductions, ushered in one of the first practical examples of the anthropic principle in modern science. The anthropic principle roughly tells us that the laws of physics ‘are what they are’ in order for the constraint that is life to exist. If you remember in Part 1, I left you back in 2006, watching the DVD logo bounce around your TV screen. You must first exist in order to observe the rare chance the logo locks perfectly into a corner, otherwise who’s to say it even happened? With the anthropic comes a fair pinch of solipsism, that we should take center stage in this story of the universe, otherwise why else would we be here?
Subjective Image of the Milky Way, 1902. Pannekoek.
Huayan Buddhism teaches us that both “all phenomena are present in each phenomenon” and that “no phenomenon knows another phenomenon”. In other words, every possible phenomenon is alone in the cosmos, which seems to also paradoxically point to the idea that every other possible phenomenon is also alone in the cosmos. Put even simpler by the Tiantai Buddhists: If I am the only being in the cosmos, who I am is also you as the only being in the cosmos. Your thoughts are transient properties that hold no true essence in their universality – I too experience them. If we accept our minds are made of all the same processes, we can argue that the notion of being a Boltzmann Observer in a randomly fluctuating universe is what D.Z. Albert would call ‘cognitively unstable’. If you can reason with yourself to believe you are a product of such a cosmological system, you also must conclude you have no justification for accepting your own reasoning. There is no reference point for the lonely solipsist.
It does seem a bit self-defeating to grant substantial confidence to the prospect that we have no right to grant substantial confidence to anything. We must satisfy ourselves then with rejecting the cosmological models in which Boltzmann Brains occupy, as they serve us little purpose in our further understanding beyond a resigned cognitive instability. That is not to say that we discard the possibility that you might still be a Boltzmann Brain given the odds. Perhaps the distant memories of 2006 and old movies on the DVD Player are indeed false, after all – how well do you remember the past anyway?
Irà Sheptûn, @iradelune
