For some time, I have been wondering whether the Boltzmann brain paradox is a genuine one. Here’s how Wikipedia describes the paradox (emphases are mine):
In physics thought experiments, a Boltzmann brain is a self-aware entity that arises due to extremely rare random fluctuations out of a state of thermodynamic equilibrium. For example, in a homogeneous Newtonian soup, theoretically by sheer chance all the atoms could bounce off and stick to one another in such a way as to assemble a functioning human brain (though this would, on average, take vastly longer than the current lifetime of the universe).
The idea is indirectly named after the Austrian physicist Ludwig Boltzmann (1844–1906), who in 1896 published a theory that the Universe is observed to be in a highly improbable non-equilibrium state because only when such states randomly occur can brains exist to be aware of the Universe. One criticism of Boltzmann’s “Boltzmann universe” hypothesis is that the most common thermal fluctuations are as close to equilibrium overall as possible; thus, by any reasonable criterion, human brains in a Boltzmann universe with myriad neighboring stars would be vastly outnumbered by “Boltzmann brains” existing alone in an empty universe.
Boltzmann brains gained new relevance around 2002, when some cosmologists started to become concerned that, in many existing theories about the Universe, human brains in the current Universe appear to be vastly outnumbered by Boltzmann brains in the future Universe who, by chance, have exactly the same perceptions that we do; this leads to the absurd conclusion that statistically we ourselves are likely to be Boltzmann brains. Such a reductio ad absurdum argument is sometimes used to argue against certain theories of the Universe.
The two assumptions I’d like to question in this post are: (i) the assumption that a Boltzmann brain could self-assemble in the first place, given enough time; and (ii) the assumption that the spontaneous self-assembly of such a brain is more likely than the spontaneous formation of human observers.
Concerning (i), I would like to point out that the brain is a multi-layered organ containing 86 billion neurons, each of which is supported by glial cells and astrocytes. Within each neuron is a nucleus, surrounded by a cell body which receives signals via dendrites and sends signals along an axon, which in turn is insulated with a myelin sheath. The idea that individual atoms could arrange themselves into a brain containing tens of billions of these multi-layered structures is simply absurd, because such a “brain” would fall apart long before it formed. Without stable intermediate stages, a brain cannot spontaneously self-assemble out of atoms, even when given an infinite amount of time.
As for (ii): it seems to me that the main argument in its favor is that thermodynamically speaking, it’s easier for an infinite box of gas in equilibrium to assemble into X than it is for the gas to assemble into X + Y. Hence the spontaneous formation of a brain alone is far more likely than the self-assembly of a brain attached to a human body, which in turn is more likely to form spontaneously than an entire planet full of organisms (including humans), which is more likely to form spontaneously than a universe full of stars and planets (including our Earth). But this kind of reasoning ignores the possibility of “springboards,” or transitional stages which generate multiple paths, some of which lead to the desired target.
Thus the likelihood of a brain forming from a box of gas is far greater if the gas is first allowed to assemble into a primordial cell, as such a cell is capable of evolving into various kinds of organisms (including humans with brains). But evolution can only proceed in a physical environment; hence we need a planet for the cell and its descendants to live on. But a planet needs a source of energy to power the chemical reactions leading to life, which in turn requires energy to power its own internal processes; hence we need a star as well. And the formation of stars is rendered more likely by the postulation of an initial Big Bang, starting from a hot, dense state. In short: while the spontaneous formation of a universe, holus bolus, is many orders of magnitude less likely than the spontaneous formation of a brain, the formation of a human being possessing a brain within the framework of a Big Bang universe which is capable of generating stars and planets, some of which are capable of generating life, which subsequently evolves into the dazzling array of creatures we see on Earth, is far more likely than the spontaneous self-assembly of a Boltzmann brain – an event whose probability I have already argued is zero.
I’d like to finish with a closing thought. Is there something wrong with the way we define entropy? Currently, physicists define it in terms of the number of possible micro-states of a system which are consistent with its macro-description (e.g. “a human brain”). This, in essence, is what Boltzmann’s entropy formula expresses. However, such a definition ignores a system’s history, and makes no attempt to calculate the number of pathways by which the atoms in the system can reach their macro-level target. Boltzmann’s definition of entropy also leads many well-meaning but misinformed laypeople to mount fallacious arguments against biological evolution. Isn’t it about time we came up with a better definition, which doesn’t generate silly paradoxes? What do readers think?
Personally the Boltzman brain thing looks like an incomprehensible mess!
Possibly false premise. It rules out the possibility the state of low entropy was the result of creation rather than a random event. The fact the premise leads to absurdities suggests the premise is false. This is a argument/proof by contradiction something is wrong with the starting assumptions!
If everything is just a major accident, well, yeah, you can guess we just might be accidentally having illusory perceptions and that we are really alone in the universe just imagining all the events around us.
It also makes the likely false assumption self-awareness is material origin. Some interpretations of Quantum Mechanics insist there must be a non-material entity (like God) in reality to make QM work, otherwise it leads to absurd paradoxes. The book Quantum Enigma of consciousness argues (implicitly) reality requires MIND to be fundamental to physics.
Boltzmann committed suicide after devoting himself to the study of statistical mechanics and thermodynamics. Very sad, but, being a fan of Darwin and being an atheist, I suppose if he thought his soul was just the product of a random roll of the dice, then killing himself was consistent with his beliefs on some level. All accounts suggest he was a decent caring man. Sad.
Makes no sense. If this life is all we get, better make it count. Which Boltzmann did.
PS seems likely he was suffering from clinical depression. Not sure whether religious belief has any bearing on one’s chances of being prone to periods of depression.
PPS one might also ask does atheism cause depression or does depression cause atheism – assuming there is any statistical link at all.
I am not sure why you say one has taken over the other. They are two separate hypotheses. BBs are a consequence of our best physics. The Simulation Hypothesis is an interesting thought experiment in philosophy.
It is true that both are global skeptical hypotheses, in the philosophical family of Plato’s cave, Descartes’ evil demon, Putnam’s brain-in-a-vat, The Matrix, and so on.
BB is different though, in that it is a scientific prediction, not just a thought experiment.
Although I suppose that if you thought ID was a science, then the simulation designer could be what it predicts. Then one could argue about a deistic simulation designer versus a tinkerer, and whether such tinkerings were detectable by our science.
Oh, wait, maybe we are already having that argument?
SC is taking BBs as an ideology, not a science.
That computer would have to be a quantum computer to simulate the experiments we do based on Bell’s results, I believe. Although maybe not if the SH included superdeterminism. Also, I suppose I am making the unwarranted assumption that we have any handle on the physics of the simulator’s world.
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Also, “action at a distance” if it means signaling is not in our quantum world (it would violate SR). QM just adds non-local correlations, but these cannot be used to signal classical bits (ie the bits we can use to make decisions; those with causal influence)
Perhaps God is in fact the simulation designer and that designer (Designer?) has chosen to reveal within-simulation knowledge to you. That would be Simulation Theology, I suppose.
Also, regarding your nested BBs and simulation hypothesis post: if you have not seen the movie Inception, you might enjoy it. It has a similar premise.
The Poincare recurrence relation is valid in say an idealized situation where molecules bounce in a box and don’t get together to become a black hole! If the universe is expanding, then the Poincare relation also fails. Hence, if the universe becomes so spread out, everything is so disconnected from each other, a “fluctuation” becomes meaningless since entropy goes to infinity. Recall that if you expand a volume of gas letting it expand isothermally and adiabatically (no heat added or subtracted or work done) into a bigger chamber, the entropy automatically increases! Expanding the universe increases entropy in an irreverisble way, hence you can’t have a fluctuation deep into the future that is a meaningful fluctuation because you just have a measily atom floating by its lonesome causally separated from all other atoms as space expands.
SO we ARE in a privileged time, and there is Time’s arrow, we are NOT, as far as we can tell, in a recurring universe. As Lawrence Krauss said:
The reductio ad absurbdum of Boltzman brains is confirmed, showing the premises are likely wrong or at least not consistent with what we regard as reality. We have to start with the assumption after all, that something is real, like pain!
I am not sure I understand what you mean by bring in the HT. Can you be more specific?
Not exactly,
God is honest and trustworthy. He could not reveal false information
A simulation is by definition not reality.
It’s one of my favorites.
I think the realization that sans God we are simply incapable of knowing whether we are dreaming or the product of someone else’s dream should be pondered till it’s weight sinks in. Usually we just skip over it and move on.
No one actually thinks that we are BBs or part of a simulation but the atheist can’t possibly justify that belief. For him it’s simply an act of blind faith in something that is very unlikely.
I’d say that understanding probably weighed on Boltzmann
peace
BruceS,
Holographic principle.
Quantum computers might just be a line of code put in after a weekend bender.
peace
Yes, I knew that was what T was referring to. I don’t understand its relevance non-locality. I do understand both are related to quantum information and that the correlations shown in comparing measurements of entangled systems are grounded in quantum information (or at least, I think I understand that).
But I am guessing that T is saying HT/HP is an explanation or grounding of this entanglement. But that is where I’d like to understand T’s point better.
Well, of course, that is exactly the type of “knowledge” a simulation designer would reveal to you.
You like SC are using BBs to make ideology claims, not scientific or philosophical claims. As I have posted, I would agree that philosophy is needed to argue you are not currently a BB. But science says BBs must exist in the far future (but this claims needs to make the assumptions documented in the second Carroll link and also respond to Allan’s arguments).
BruceS,
Doesn’t look like it’s been tested yet or even that there is consensus on what such a test could involve.
Surprisal. If I’m some sort of simulation, how come I’m continually surprised? Or does that just refute solipsism?
If it is a simulation a la Bostrom, then there is no reason to think you would be any different than you are now. So Scott A says, correctly IMHO, that Bostrom’s idea can be ignored in practice.
If by “refute solipsism” you mean logically rule out, then nothing can, I suspect. On the other hand, why ask such a question unless maybe you think the answer is buried in your solipsist subconscious and asking yourself will make it conscious?
Here is a possibly relevant philosophical anecdote related to the simulation stuff. There is another anecdote related to the solipsist question which I leave as an exercise for the Googler.
[start of anecdote]
“Tell me,” Wittgenstein’s asked a friend, “why do people always say, it was natural for man to assume that the sun went round the earth rather than that the earth was rotating?” His friend replied, “Well, obviously because it just looks as though the Sun is going round the Earth.” Wittgenstein replied, “Well, what would it have looked like if it had looked as though the Earth was rotating?”:
You might like this:
https://www.academia.edu/33781223/Beliefs_in_a_Vat?source=swp_share
It’s physical structure capable of carrying a thought. The same issues apply, even when one decides to appeal to physical structures not known to exist. In fact, the problems I’m alluding to would apply to a simple house-brick.
If materialism is true it may still be the case that thoughts require a structure along the lines of our own
No, but practicality is. Thinking structures might be possible in a black hole plasma or a diffuse collection of photons, but I see no reason to simply accept this as a given.
Here’s a question – a rhetorical one: if you are a BB, how come you arose out of physics which you only imagined?
Allan Miller,
That’ll surprise him!
That is not a rhetorical question at all. It is exactly the question that leads to the philosophical argument concluding that you are not a BB. That’s the argument that the philosopher David Albert develops, Carroll repeats, and I try to quote upthread. Rumraket makes a similar philosophical point upthread.
The only adjustment would be to add that it is not coherent for you to argue you are a BB on the basis of physics, since if you are, there is no rational basis for the physics you are using.
That was fun in the same way BBs are. I do admit I ran out of intellectual gas in the latter part where she applies Wittgenstein’s PLA to the objections.
However, I suspect the paper’s argument would not meet the KeithS standard for refuting his Cartesian skepticism. Whether that should enter be one’s standard for irrefutable logic, I will leave as rhetorical red cape wave for him, should he be lurking.
The argument also seemed to rely on the assumption that one is an isolated brain in a vat. But I don;t think it works for the Matrix, where there is a community of people communicating in language about a common world which is a causal source for their perceptions. Just not the source we think it is when we are not doing philosophy.
I think the same issue arises if the argument were to be applied to a Bostrom simulation.
Ha ha, nope. That’s not only not true, it’s also inconsistent with Reid, who you claim to understand and admire.
I don’t think you understand what universal Turing machines are.
If thoughts are computations then any ole computer will do. For the same reason that you can run Microsoft software on a apple computer. The simplest computer possible can do any computation it just takes longer.
Of course you could argue that thoughts aren’t like computations and brains are not like computers. That is a position I happen to agree with. But most folks here think that strong AI is at least a possibility.
peace
LOL here we go again
Here is the quote from Reid that Walto and I discussed earlier.
quote:
I thank the Author of my being, who bestowed it upon me before the eyes of my reason were opened, and still bestows it upon me, to be my guide where reason leaves me in the dark. And now I yield to the direction of my senses, not from instinct only, but from confidence and trust in a faithful and beneficent Monitor, grounded upon the experience of his paternal care and goodness. In all this, I deal with the Author of my being, no otherwise than I thought it reasonable to deal with my parents and tutors. I believed by instinct whatever they told me, long before I had the idea of a lie, or thought of the possibility of their deceiving me
end quote: (Reid, Inquiry, in Works of, I.184).
That is exactly my position!!!!!!.
My position is not just consistent with Ried it’s literally exactly the same as his in this regard.
And it’s a position that is simply impossible to hold sans God.
I will grant that Reid did not spend a lot of time asking atheists to ponder where the principles of common sense come from but he knew full well he owed his confidence to God’s graciousness.
Of course It was a different time. He was involved in an argument with folks who denied that we could trust our senses. But he would never ever pretend that we could trust our senses if God did not exist.
peace
P.S.
Also notice that Ried considers normal everyday sense experience to be “dealing with the author of my being”. It sounds a lot like what I’m getting at when I say revelation.
Yes and his deceitfulness in this area would prove that he was not God and therefore not worthy of my worship.
It would also mean that I could not trust his truthfulness in other areas.
The only way I can ever trust that the impressions of my senses and reasoning faculties are veridical is if they were given to me by a loving and faithful God.
peace
Regarding the Poincare recurrence theorem and Boltzman’s Universe, suppose you have 10 fair coins. Every now and then ( like say 1 out 2^10 trials on average), you’ll get all heads. In principle you can take this out to N-number of coins, but then this becomes and absurd number, but ok, on infinite time scales it will repeat.
The problem is the recurrence theorem works well when you have an infinite universe where numerous trials can take place. By way of analogy, if some sort of permanent glue were used to glue the coins down so they won’t flip anymore, then one will not have recurrence of the same coin configuration! In analogous manner, there are some irreversible features of the universe where recurrence can’t happen, hence the Boltzman universe can’t have those fluctuations in the future even on infinite timescales since stuff will just be plain spread out to oblivion in a Big Bang scenario. And if Christian God made the universe in miraculous act of creation, then the universe is winding down and coming apart irreversibly. Forget any fluctuations from equilibrium in the distant future.
My point is, there are simpler more elegant ways to argue features of the universe without resorting to in-elegant proof-by contradiction that involves multiple premises, where you can’t tell specifically which premise is actually falsified.
There are several premises, or at least two I can identify:
1. eternal universe
2. a thermal fluctuation is sufficient to create a Boltzman Brain in an empty universe (huh?) and that brain can give us all of our experiences
I don’t know if I can go on. The whole argument looks like a mess.
A question’s rhetorical nature is not determined by its originality!
So if I make a computer out of basketballs and have snails shuffle them around, the system will suffer existential angst? Prove it.
Allan, to fifth:
Fifth doesn’t believe that it will:
BruceS,
Irrefutable! 🙌
Alan:
We’ve been over this before:
Alan:
keiths:
Alan:
keiths:
keiths,
I know. You never disappoint in this regard.
Alan,
If a simulation of a processor chip can surprise its creators, why do you think that no simulation could ever surprise you?
Another example: Edward Lorenz was surprised by the behavior of his weather simulations, leading to his pioneering work on chaos theory and the coining of the term “butterfly effect”.
That’s undecidable.
Not following. Because Lorentz was surprised at something that indicates that BBs are possible? I say BBs are undecidable but Allan’s point is persuasive.
I’m misreading perhaps. I’m talking solipsism. Not surprisal by a simulation, surprisal as a simulation.
Alan:
No. We’re talking about simulations, not Boltzmann brains, though you appear to have been confusing the two in this exchange with Bruce:
Bruce:
Alan:
My point is that simulations can behave in surprising ways. Lorenz was surprised by the behavior of his weather simulations. My colleagues and I have been surprised (many times) by the behavior of our chip simulations. Talk to scientists and engineers across a broad range of disciplines and you’ll hear similar stories.
So when I wrote this…
…and you responded with this…
…your response made no sense.
Simulations can surprise, and they are certainly imaginable.
Just so. The problem as I see it is that you cannot tell the two possibilities apart.
It’s quite possible to hold both positions: human brains do not operate like digital computers and also strong AI is possible. As in fact I do.
That of says nothing about phenomenal experience, only intelligence.
Just to be clear, I meant rhetorical in the sense of “asked merely for effect with no answer expected”.
So your post was not rhetorical in that sense, that is in terms of importance to the debate on whether one is currently a BB. Of course, I make no claims about your motives in posting!
ETA: The italicizing of ‘philosophical’ in my post to you was also meant to be non-rhetorical.
Maybe this post is rhetorical, however.
Wait a minute. AI is based on the idea that intelligence can be “simulated” by a computer.
If you hold that you can’t get there that way but can still get there by some other route you are not talking about AI but something else entirely.
peace
I can tell them apart if God chooses to reveal himself to me. He can do that because he is omnipotent.
If something or someone is knowable I can know because …….God.
peace
I agree I am not talking about AI the way you understand it. Rather, I am talking AI the way modern science and philosophy understands it.
Nothing in that logical contradicts my point. Hint: Focus on the “if” part.
You are going to have to show me some research in AI that does not involve computers.
In essence what you are claiming is that you can’t ever know a person as he truly is.
I would beg to differ.
peace
An AI system competed against a human debate champion. Here’s what happened
The article makes an important point about the role of emotion in human judgments of the winner’s debate.
But is also makes a mistake when it says”
“Of course, the AI wasn’t inventing ethical positions of its own and trying to push them on us humans. It was just pulling from statements humans have already made and strategically spitting those back at us.”
The mistake is this: implying this is a constitutive difference between human and AI intelligence. For how much of the above is true of humans as well? That question needs to be addressed.
Well, you can actually argue the reverse: that you can never know yourself except through both the interactions with others and the world in general. Wittgenstein’s PLA and Putnam’s externalism about meaning are two ways of doing that.
And with that I will bow out of this exchange.
BruceS,
The AI definitely involved a computer in that paper.
What else do you have?
peace