10 ms·

Boltzmann brain

148 points by josephwegner 2y ago

bee_rider 2y ago
Hmm. Is a Boltzmann brain incompatible with quantum immortality? I guess it is possible, just unlikely, that you’ll end up as a Boltzmann brain that just happens to not dissipate, right?
rzzzwilson 2y ago
Clicked on the link hoping it was a wickedly funny parody but, alas, it's just title gore: *brain*.
- dang 2y ago
  We fixed the title (it was originally "Boltzmann Brian")
  - Vecr 2y ago
    I think someone associated with Stephen Hawking once made that joke.
joegibbs 2y ago
The problem with the Boltzmann brain, and the reason you’re almost certainly not one, is that if you are one then your senses have no relation to reality - including the part of reality where you read about the Boltzmann brain concept, or any measurements you can make about the underlying reality that makes you think you could be one. This is the same with all solipsistic arguments, like simulation hypothesis. If the universe is, in fact, an illusion, then how do you truly know anything about the real world? Sure it could be a computer simulation, but there’s no way to know for sure. The parent universe could actually follow different laws entirely. It could be creating a ”simulation” through entirely different methods. Hell, for all you know it could be an evil demon using magic to trick us, because magic could be real in the parent universe. It’s all unfalsifiable.
- CamperBob2 2y ago
  Also, any line of inquiry that applies probabilistic arguments to evolution-based questions is already off in the weeds. The brains in our bodies didn't arise as a result of pure random organization, but developed incrementally in a direction that maximized reproductive fitness. There is no reason to think that brains appearing in isolated space at random, complete with memories, would ever be a thing. So it's simply not meaningful to ask about the relative odds of these two positions.
  - empath75 2y ago
    > There is no reason to think that brains appearing in isolated space at random, complete with memories, would ever be a thing. There are only a limited amount of physical states possible in a given volume and given an infinite amount of time and space, all of them will happen an infinite amount of times.
    - wutwutwat 2y ago
      I disagree. I once had someone say that if you were to smash an iphone into tiny tiny pieces and put it into a plastic bag and shake it, given enough time, it would reassemble itself into a working iphone, the pieces randomly ending up where they need to be in order to operate like it did originally. While it is technically possible for that to happen, the probability of the intricacies that make up the iphone's circuits and screen, the chemicals that make up the battery, etc, assembling themselves into a complete and working phone, even on an infinite timeline, is not that high. And it could, in theory, never actually happen, since if there is still time that you can move forward into, there's still the chance that the moment the iphone assembles itself into a working phone lies somewhere in the future, and always will. It could just never happen before the heat death of the universe. Possibility does not guarantee probability.
      - kstrauser 2y ago
        I'm not sure. Quantum tunneling is a thing. Given the possibility of particles deciding to spontaneously just up and teleport to a nearby location, the available options increase significantly.
deleted 2y ago
[deleted]
dang 2y ago
Related: You do not need to worry about the argument that you are a Boltzmann brain - https://news.ycombinator.com/item?id=41031300 https://news.ycombinator.com/item?id=41031300 - July 2024 (1 comment) Boltzmann Brain - https://news.ycombinator.com/item?id=22079253 https://news.ycombinator.com/item?id=22079253 - Jan 2020 (149 comments) Boltzmann Brain - https://news.ycombinator.com/item?id=12152658 https://news.ycombinator.com/item?id=12152658 - July 2016 (17 comments) Boltzmann brain - https://news.ycombinator.com/item?id=6999074 https://news.ycombinator.com/item?id=6999074 - Jan 2014 (18 comments)
shagie 2y ago
Seven years ago, PBS Space time did an episode on Are You a Boltzmann Brain? https://youtu.be/nhy4Z_32kQo https://youtu.be/nhy4Z_32kQo (this was also linked in the 2020 post https://news.ycombinator.com/item?id=22080393 https://news.ycombinator.com/item?id=22080393 )
- homebrewer 2y ago
  See also this fantastic podcast (if I remember the episode correctly, although it doesn't matter much as they're all good and he talks about the subject frequently because it's tightly related to his day job) https://www.preposterousuniverse.com/podcast/2022/06/06/200-solo-the-philosophy-of-the-multiverse/ https://www.preposterousuniverse.com/podcast/2022/06/06/200-...
unholiness 2y ago
The way I see it: The reasonable things that continue happening each day in our universe would be extremely unlikely if we are just Boltzman brains. Every bit of sensible reality would be coincidental. The very continuance of that reality is an experiment constant proving the falsehood of Boltzman brains, at a rate of oh maybe millions of sigmas of confidence per second. Now, if you believe the universe came to an initial state due to pure thermodynamic coincidence, millions of sigmas per second is laughably small compared to the chance that a whole universe outside your brain popped into existence, so Boltzman brains are the most believable thing and you should believe in them. This completes a pretty direct argument: Believing the initial state of the universe was a thermodynamic coincidence forces you to believe in Boltzman brains, Boltzman brains force you to believe reality should collapse immediately, and reality does not collapse immediately. Therefore you simply can't believe the first assumption, that initial state of the universe was a thermodynamic coincidence. Accepting this is often called the "Past Hypothesis". It's spoken of in deferential terms and said that it can't ever be proven... But to me this is rock-solid proof, with more sigmas of evidence than any other scientific discovery and increasing by the second! Can't we just call it the Past Theorem already?
- yoru-sulfur 2y ago
  I am mostly playing devil's advocate > and reality does not collapse immediately How do you know that reality does not collapse immediately? At any given instant you could be a fresh brain that just came into existence, all your previous memories which imply a life lived up to this point also formed in that same instant.
  - XorNot 2y ago
    Indeed the bigger issue as I see it is that the only "sensible reality" that can exist is the one you subjectively experience. Since that one is the only sensible one, it's the only one you perceptually would be able to hang around for - even if it's actually a conincidental series of flickers of sapience across trillions and trillions of years. i.e. a time stepped simulation, absent external reference, doesn't know how long it's been between the actual steps - could be seconds, could be hours, could be years. EDIT: Like the real issue with "death" is that it's not "eons on darkness" - which is why I think people get afraid of it (or one of the reasons) - but that actual, literal non-existence is inconceivable even though we all did it - 13 billion years of not-existing in the universe, then suddenly you. So after you die the same problem re-emerges: the conscious experience of "you" ends...but then from the subjective blink of an eye if something happens to restart that information process just right, suddenly again, you - and it has to be you, and no one else, because if it wasn't then well, it would be someone else - i.e. why am I me, and not my wife or son for example?
smokedetector1 2y ago
I dont need to logically disprove theories like this, because I experience myself in a way that you can't argue against. Trying to convince me my experience of myself is an illusion is, in my view, a horrible case of trying to fit reality to your model. Yet it's one that a surprising number of scientifically minded people enjoy doing, for some reason. Beats me.
- kempje 2y ago
  Here's a different way of thinking about it. There are two things that are both very plausible: One - based on your direct personal experience - is that you are a non-boltzmann-brain-human living a normal life on earth. Two - based on well-accepted science - is that it is MUCH more likely for you to be a boltzmann brain than not. Great; these two things are seemingly inconsistent. Which means one must be false. But if either of these is false, it's surprising! Because one is based on our direct experience of ourselves, as you have pointed out, and the other is based on well-established science. So what's interesting about Boltzmann brain (and similar) is that it shows that one part of our body of knowledge must be false. And this ought to motivate us to investigate exactly what it is that we have wrong.
  - NoMoreNicksLeft 2y ago
    None of these are even the interesting points. Arguing about whether you or I are a BB is meaningless. What I want to know is this: will BBs exist in the immeasurably far future? If they will exist, how fast could they possibly think, how long could they last, and what is the limit on their intelligence? Could they comprehend their own existence from first principles? In the short instants that they exist, would they realize how short their life expectancy is? >Two - based on well-accepted science - is that it is MUCH more likely for you to be a boltzmann brain than not. We're not each individual BBs (and you're not a lonely BB imagining the rest of us). It's closer to the truth that our entire universe is one big BB that just blipped into existence one moment billions of years ago. If we accept the concept of a Boltzmann Brain at all, then it must be that some configurations of one where parts of the brain are disconnected from each other and each spawns and intelligence... or even just unintelligent matter/machinery. Scale that up to a few billion light years wide, and that's us.
kempje 2y ago
There is a widely circulated (amongst philosophers) argument against the Boltzmann brain hypothesis made on bayesian grounds. Technical, but very interesting. It's being published next year in what's generally regarded as the top academic journal for philosophy: https://philpapers.org/archive/DOGWIA-6.pdf https://philpapers.org/archive/DOGWIA-6.pdf
- int_19h 2y ago
  Their argument hinges on one particular claim: > As unlikely as it is for a BB to form at all, it’s drastically more unlikely for additional things to simultaneously form around it. And even if additional things did form around the BB, it is not especially likely they will be the kind of stable and sensible objects a brain could even perceive. Therefore, the evidence we have is more likely supposing we are OOs than supposing we are BBs. which doesn't ring true to me. Assuming that universe is indeed dominated by BBs, it's not at all clear to me that any observations we could possibly make "is more likely supposing that we are OOs". While the number of BBs "with decorations" would be dwarfed by the number of BBs without, it is still entirely feasible that there are many more such BBs than there are OOs. I also found their argument as to why all observations shouldn't be considered hallucinations (including "over time", "history of" etc) as a matter of probability to be incomprehensible.
  - crdrost 2y ago
    It's philosophically gauche but I often like to criticize arguments based on “what if they were right?”... So for example the ontological argument putatively argues for the existence of a Perfect Being but it would seem to work even if you restricted the domain somewhat to something smaller than “all beings”, and so presumably also argues for the existence of a perfect Toaster. Similarly here, the claim is that in a BB universe, even though countlessly more brains see the exact same stuff as you, there is something about the Bayesian update factor that you all have where you all still should conclude you are not the Boltzmann Brains and the evidence is never enough. How do you look at that description, and not conclude that according to that argument, Bayesian reasoning is just strictly wrong? Like everyone (more or less) is “it” and everyone (more or less) says “it’s not me!” and everyone (more or less) is wrong and here is our philosopher dusting their hands saying ‘yep! sounds good, solved the problem!’
stevebmark 2y ago
It's intuitive and obvious that nothing remotely like a Boltzmann brain has ever existed nor will ever exist. The misunderstanding comes from the common, but fundamentally wrong belief, that an infinite universe means infinite possibilities.
- 867-5309 2y ago
  let's not elaborate on those fundaments though
throwup238 2y ago
> Over a sufficiently long time, random fluctuations could cause particles to spontaneously form literally any structure of any degree of complexity, including a functioning human brain Can anyone explain this bit to me? The formation of biological brains was a multi-billion year climb against entropy. How would a brain form spontaneously without those random fluctuations tearing the constituent components apart? I’m having trouble understanding the logic here. Random fluctuations don’t imply that any order from those fluctuations can be preserved. The higher order features like brains are path dependent on something resisting those random fluctuations to allow something stable to form, whether that’s an atomic particle, cell, organ, or organism. IANAP and I don’t know what I’m talking about
- quantadev 2y ago
  It's about quantum mechanics and the fact that "empty space" is not really empty. Particles do pop into existence (from nothing), according to QM, so there's a non-zero probability for any "pattern" to pop into existence. Sort of like if you have an infinite number of coin flips then at some place and time you'll land on heads a million times in a row, no matter how unlikely. And for any million-bit sequence you're guaranteed to hit it too. So a human "brain" is just a pattern that's likewise guaranteed to be "encountered". A similar concept is how the first replicator RNA/DNA got created as the beginning of life. If RNA can exist in large numbers of random sequences, then a sequence that can replicate itself only has to "happen" once and then life is started and will never slow down but will grow in complexity, as long as the environment can support it.
  - throwup238 2y ago
    I get the part about popping into existence but how would even so much as a bilipid layer around a single cell form, let alone a whole brain? Where are all the antiparticles in this, except shooting around? Even if all the particles pop into existence perfectly placed for a single quanta of Plank time, aren’t the antiparticles destructively interfering with all the other particles even before they begin to annihilate? I imagine they would prevent any chemical reaction happening at all at that density. What about all the force carriers? Can they even pop into existence in the quantum foam coupled? It wouldn’t really resemble a brain in biological sense of the world because the only stimuli it can and will react to is its own disintegration. It’s hard to justify it even “existing” at all. A “virtual” brain in the sense of virtual particles perhaps, except it seems quantitatively useless.
quantadev 2y ago
The "Big Bang" theory (BBT) is equally as absurd as the Boltzmann brain conjecture, and recent evidence from the James Webb Space Telescope provides even more evidence against the BBT, by showing there are too many mature universes near the theorized "beginning of time" and also the Hubble expansion is off by 8%. I think there's more and more evidence that we're instead in a 3D reality that's the manifold (surface) of an Event Horizon. We're neither inside nor outside a black hole, but on the boundary of one. All Black Holes form from matter "falling in" rather than stuff "exploding out", and that's how our universe formed (as a Black Hole, one dimension higher up than normal 2D black holes we see). The general rule is that any N-dimensional reality is on an Event Horizon and will have contained/embedded within it (N-1)-dimensional other black holes (it's a hierarchy). The JWT also just showed our universe is expanding at a rate that's also inconsistent with our current Big Bang theory, and is off by a whopping 8%. I think the reason we see the expansion is not because of Dark Energy (which likely doesn't even exist), but is because the surface of all Event Horizons only expands over time, or in the case of a 3D (excluding time dimension) Universe we see more and more of volumetric space forming, because it's a volumetric expansion for us, rather than the "area" (2d) expansion on conventional 2D Black Holes. I also think the surface normal vector (perpendicular) vector, at any point on such a manifold (Event Horizon) will be experienced as a "time" dimension. That's why time is a "special" variable. Thus time only moves forward whenever the event horizon "grows" (due to matter falling in from outside it)
- post-it 2y ago
  You can always rely on HN to produce a software guy with a unique hypothesis about how the universe and/or the economy actually works.
  - quantadev 2y ago
    I've been convinced of this theory for about 10 years. I don't know why people can't wrap their heads around a 3D version of the Holographic Principle (as opposed to the standard 2D version of it, per Susskind, etc.), or indeed an N-dimensional-manifold version of it. This guy did tho... (he gets into the good part right at about halfway thru) https://www.youtube.com/watch?v=A8bBhkhZtd8 https://www.youtube.com/watch?v=A8bBhkhZtd8
khana 2y ago
[dead]
Pigalowda 2y ago
Extreme solipsism is a navel gazing Boltzmann brain. The runners up are brains in jars and simulation theory. I feel like a Boltzmann brain knowing that it’s a Boltzmann brain is too good to be true. Might as well make the god of Abraham out of entropy - if you can get a regular Boltzmann brain, why not get the most powerful Boltzmann? Maybe it will take trillions of attempts over trillions of universe births and deaths. But you only need it to work the once.
cakealert 2y ago
A snapshot of an instance of you is just a really large number. A unique transition between two instances of you (@ t and t+1) is also a large number. A slideshow of your entire life's instances is just a really really large number. All these numbers are somewhere on the number line. In fact, the slideshow of every creature is on the number line. Is anything real? Because being instantiated in matter is just another way of animating the slideshow where physics takes care of the transition function. There are unfortunately no insights to be had in this endeavor.
Balgair 2y ago
I just want to point out that the time for one to randomly appear is somewhere between 10^10^50 and 10^10^69, which is is a pretty large gap. Like the difference between the two is just 10^10^69, mostly. I'll point out here that I'm not using units. The article does, but it's not like they really mean anything at these time scales. A plank time (10^-43 s) to the age of the current universe (10^9 yr) to the lower bound for the estimated time until the heat death of the universe (10^109 yr), all of those time units just end up as rounding errors compared to the lower limit of 10^10^50. The article does not go over here the time that such a brain could last for, but given that it's quantum mumbo jumbo, we can again assume something in the times of 10^-43s to 10^109 yr. Which, again, means that such a brain can hardly be said to have ever have existed in the first place compared to the time of it's formation probability. And yes, that means our current universe is in the same 'meh, just round it off' bucket. Like, we get caught up in the minutiae of this thing's mind, it's perceptions, it's sanity, it's soul (?). But if anything the absurdist thought experiment ends as just a mirror aimed at ourselves, with the void now creeping in behind our hats. What am I? What is perception? What is time? Can any of this ever possibly matter compared to these might-as-well-be infinities? Oh God! I've put numbers up here, they are very poor estimates mostly. And then I tell you that these numbers are so huge that, very literally, nothing that will ever exist in our universe can be made to understand that far future in which this absurd quantum brain comes out of. That time ceases to have any meaning at all in this not quite so empty quantum vacuum. So, having looked into this mirror, I don't know what tell you. I'm going for a walk, enjoy the season here, hug the fam, have a coffee, laugh, run, play. The universe has spared us this moment.
Geee 2y ago
I find it weird that they consider "particles which fluctuate", but these particles are a part of the universe already. There's nothing to fluctuate when the universe doesn't exist. However, if something fluctuates somewhere eternally, then I'd say that it's possible that this random fluctuation causes a very simple computer to form which is able to update it's state based on some simple rules, which results in complexity, i.e. our universe. This way you wouldn't need complexity to pop up spontaneously, but just a simple thing which is able to simulate a complex thing.
fourthark 2y ago
> Seth Lloyd has stated, "They fail the Monty Python test: Stop that! That's too silly!"
simonh 2y ago
The problem with this is that the vast majority of such brains would be a mess. Their experience, cognition, etc would be completely incoherent. Only a teeny, tiny, minuscule fraction of them would have coherent experiences that make sense. So if the argument is we're most likely to be such brains, then we are most likely to exist in a haze of incoherence. We don't. Right now I have an experience of a coherent historic memory, intentionality, sensory experiences, all of which make sense in the instant. If I am a random Bolzmann brain none of that should be true. So we'd have to have a reason to suppose that the minuscule fraction of coherent, consistent random Bolzmann brains are more likely than the occurrence of environments that generate 'actual' brains, each of which may generate many, many such brains.
725686 2y ago
I find the idea of a Boltzmman brain ridiculous. It is impossible for a random interactions of particles form such complexity. I find Lee Cronin's assembly index a great argument against this. Complex things such as living organisms, and brains, contain as integral part of themselves time. Not just time, as in infinite time, but evolutionary time.
- GoblinSlayer 2y ago
  Here's a counterexample: https://kundor.github.io/Finding-Waldo/ https://kundor.github.io/Finding-Waldo/
  - 725686 2y ago
    No it is not. A bunch of pixels that form an image has nothing to do with stuff that was generated by evolution. Brains don't get assembled just by pushing together atoms or molecules at random, the evolved over eons going through a lot of intermediate stages.
NoZZz 2y ago
Oh jesus H ch. no one wants Boltzmann's brain, they would go insane.

148 points by josephwegner 2y ago

Hmm. Is a Boltzmann brain incompatible with quantum immortality? I guess it is possible, just unlikely, that you’ll end up as a Boltzmann brain that just happens to not dissipate, right?

rzzzwilson 2y ago

Clicked on the link hoping it was a wickedly funny parody but, alas, it's just title gore: *brain*.

dang 2y ago
We fixed the title (it was originally "Boltzmann Brian")
- Vecr 2y ago
  I think someone associated with Stephen Hawking once made that joke.

joegibbs 2y ago

The problem with the Boltzmann brain, and the reason you’re almost certainly not one, is that if you are one then your senses have no relation to reality - including the part of reality where you read about the Boltzmann brain concept, or any measurements you can make about the underlying reality that makes you think you could be one. This is the same with all solipsistic arguments, like simulation hypothesis. If the universe is, in fact, an illusion, then how do you truly know anything about the real world? Sure it could be a computer simulation, but there’s no way to know for sure. The parent universe could actually follow different laws entirely. It could be creating a ”simulation” through entirely different methods. Hell, for all you know it could be an evil demon using magic to trick us, because magic could be real in the parent universe. It’s all unfalsifiable.

CamperBob2 2y ago
Also, any line of inquiry that applies probabilistic arguments to evolution-based questions is already off in the weeds. The brains in our bodies didn't arise as a result of pure random organization, but developed incrementally in a direction that maximized reproductive fitness. There is no reason to think that brains appearing in isolated space at random, complete with memories, would ever be a thing. So it's simply not meaningful to ask about the relative odds of these two positions.
- empath75 2y ago
  > There is no reason to think that brains appearing in isolated space at random, complete with memories, would ever be a thing. There are only a limited amount of physical states possible in a given volume and given an infinite amount of time and space, all of them will happen an infinite amount of times.
  - wutwutwat 2y ago
    I disagree. I once had someone say that if you were to smash an iphone into tiny tiny pieces and put it into a plastic bag and shake it, given enough time, it would reassemble itself into a working iphone, the pieces randomly ending up where they need to be in order to operate like it did originally. While it is technically possible for that to happen, the probability of the intricacies that make up the iphone's circuits and screen, the chemicals that make up the battery, etc, assembling themselves into a complete and working phone, even on an infinite timeline, is not that high. And it could, in theory, never actually happen, since if there is still time that you can move forward into, there's still the chance that the moment the iphone assembles itself into a working phone lies somewhere in the future, and always will. It could just never happen before the heat death of the universe. Possibility does not guarantee probability.
    - kstrauser 2y ago
      I'm not sure. Quantum tunneling is a thing. Given the possibility of particles deciding to spontaneously just up and teleport to a nearby location, the available options increase significantly.

deleted 2y ago

[deleted]

dang 2y ago

Related: You do not need to worry about the argument that you are a Boltzmann brain - https://news.ycombinator.com/item?id=41031300 https://news.ycombinator.com/item?id=41031300 - July 2024 (1 comment) Boltzmann Brain - https://news.ycombinator.com/item?id=22079253 https://news.ycombinator.com/item?id=22079253 - Jan 2020 (149 comments) Boltzmann Brain - https://news.ycombinator.com/item?id=12152658 https://news.ycombinator.com/item?id=12152658 - July 2016 (17 comments) Boltzmann brain - https://news.ycombinator.com/item?id=6999074 https://news.ycombinator.com/item?id=6999074 - Jan 2014 (18 comments)

shagie 2y ago

Seven years ago, PBS Space time did an episode on Are You a Boltzmann Brain? https://youtu.be/nhy4Z_32kQo https://youtu.be/nhy4Z_32kQo (this was also linked in the 2020 post https://news.ycombinator.com/item?id=22080393 https://news.ycombinator.com/item?id=22080393 )

homebrewer 2y ago
See also this fantastic podcast (if I remember the episode correctly, although it doesn't matter much as they're all good and he talks about the subject frequently because it's tightly related to his day job) https://www.preposterousuniverse.com/podcast/2022/06/06/200-solo-the-philosophy-of-the-multiverse/ https://www.preposterousuniverse.com/podcast/2022/06/06/200-...

unholiness 2y ago

The way I see it: The reasonable things that continue happening each day in our universe would be extremely unlikely if we are just Boltzman brains. Every bit of sensible reality would be coincidental. The very continuance of that reality is an experiment constant proving the falsehood of Boltzman brains, at a rate of oh maybe millions of sigmas of confidence per second. Now, if you believe the universe came to an initial state due to pure thermodynamic coincidence, millions of sigmas per second is laughably small compared to the chance that a whole universe outside your brain popped into existence, so Boltzman brains are the most believable thing and you should believe in them. This completes a pretty direct argument: Believing the initial state of the universe was a thermodynamic coincidence forces you to believe in Boltzman brains, Boltzman brains force you to believe reality should collapse immediately, and reality does not collapse immediately. Therefore you simply can't believe the first assumption, that initial state of the universe was a thermodynamic coincidence. Accepting this is often called the "Past Hypothesis". It's spoken of in deferential terms and said that it can't ever be proven... But to me this is rock-solid proof, with more sigmas of evidence than any other scientific discovery and increasing by the second! Can't we just call it the Past Theorem already?

yoru-sulfur 2y ago
I am mostly playing devil's advocate > and reality does not collapse immediately How do you know that reality does not collapse immediately? At any given instant you could be a fresh brain that just came into existence, all your previous memories which imply a life lived up to this point also formed in that same instant.
- XorNot 2y ago
  Indeed the bigger issue as I see it is that the only "sensible reality" that can exist is the one you subjectively experience. Since that one is the only sensible one, it's the only one you perceptually would be able to hang around for - even if it's actually a conincidental series of flickers of sapience across trillions and trillions of years. i.e. a time stepped simulation, absent external reference, doesn't know how long it's been between the actual steps - could be seconds, could be hours, could be years. EDIT: Like the real issue with "death" is that it's not "eons on darkness" - which is why I think people get afraid of it (or one of the reasons) - but that actual, literal non-existence is inconceivable even though we all did it - 13 billion years of not-existing in the universe, then suddenly you. So after you die the same problem re-emerges: the conscious experience of "you" ends...but then from the subjective blink of an eye if something happens to restart that information process just right, suddenly again, you - and it has to be you, and no one else, because if it wasn't then well, it would be someone else - i.e. why am I me, and not my wife or son for example?

smokedetector1 2y ago

I dont need to logically disprove theories like this, because I experience myself in a way that you can't argue against. Trying to convince me my experience of myself is an illusion is, in my view, a horrible case of trying to fit reality to your model. Yet it's one that a surprising number of scientifically minded people enjoy doing, for some reason. Beats me.

kempje 2y ago
Here's a different way of thinking about it. There are two things that are both very plausible: One - based on your direct personal experience - is that you are a non-boltzmann-brain-human living a normal life on earth. Two - based on well-accepted science - is that it is MUCH more likely for you to be a boltzmann brain than not. Great; these two things are seemingly inconsistent. Which means one must be false. But if either of these is false, it's surprising! Because one is based on our direct experience of ourselves, as you have pointed out, and the other is based on well-established science. So what's interesting about Boltzmann brain (and similar) is that it shows that one part of our body of knowledge must be false. And this ought to motivate us to investigate exactly what it is that we have wrong.
- NoMoreNicksLeft 2y ago
  None of these are even the interesting points. Arguing about whether you or I are a BB is meaningless. What I want to know is this: will BBs exist in the immeasurably far future? If they will exist, how fast could they possibly think, how long could they last, and what is the limit on their intelligence? Could they comprehend their own existence from first principles? In the short instants that they exist, would they realize how short their life expectancy is? >Two - based on well-accepted science - is that it is MUCH more likely for you to be a boltzmann brain than not. We're not each individual BBs (and you're not a lonely BB imagining the rest of us). It's closer to the truth that our entire universe is one big BB that just blipped into existence one moment billions of years ago. If we accept the concept of a Boltzmann Brain at all, then it must be that some configurations of one where parts of the brain are disconnected from each other and each spawns and intelligence... or even just unintelligent matter/machinery. Scale that up to a few billion light years wide, and that's us.

kempje 2y ago

There is a widely circulated (amongst philosophers) argument against the Boltzmann brain hypothesis made on bayesian grounds. Technical, but very interesting. It's being published next year in what's generally regarded as the top academic journal for philosophy: https://philpapers.org/archive/DOGWIA-6.pdf https://philpapers.org/archive/DOGWIA-6.pdf

int_19h 2y ago
Their argument hinges on one particular claim: > As unlikely as it is for a BB to form at all, it’s drastically more unlikely for additional things to simultaneously form around it. And even if additional things did form around the BB, it is not especially likely they will be the kind of stable and sensible objects a brain could even perceive. Therefore, the evidence we have is more likely supposing we are OOs than supposing we are BBs. which doesn't ring true to me. Assuming that universe is indeed dominated by BBs, it's not at all clear to me that any observations we could possibly make "is more likely supposing that we are OOs". While the number of BBs "with decorations" would be dwarfed by the number of BBs without, it is still entirely feasible that there are many more such BBs than there are OOs. I also found their argument as to why all observations shouldn't be considered hallucinations (including "over time", "history of" etc) as a matter of probability to be incomprehensible.
- crdrost 2y ago
  It's philosophically gauche but I often like to criticize arguments based on “what if they were right?”... So for example the ontological argument putatively argues for the existence of a Perfect Being but it would seem to work even if you restricted the domain somewhat to something smaller than “all beings”, and so presumably also argues for the existence of a perfect Toaster. Similarly here, the claim is that in a BB universe, even though countlessly more brains see the exact same stuff as you, there is something about the Bayesian update factor that you all have where you all still should conclude you are not the Boltzmann Brains and the evidence is never enough. How do you look at that description, and not conclude that according to that argument, Bayesian reasoning is just strictly wrong? Like everyone (more or less) is “it” and everyone (more or less) says “it’s not me!” and everyone (more or less) is wrong and here is our philosopher dusting their hands saying ‘yep! sounds good, solved the problem!’

stevebmark 2y ago

It's intuitive and obvious that nothing remotely like a Boltzmann brain has ever existed nor will ever exist. The misunderstanding comes from the common, but fundamentally wrong belief, that an infinite universe means infinite possibilities.

867-5309 2y ago
let's not elaborate on those fundaments though

throwup238 2y ago

> Over a sufficiently long time, random fluctuations could cause particles to spontaneously form literally any structure of any degree of complexity, including a functioning human brain Can anyone explain this bit to me? The formation of biological brains was a multi-billion year climb against entropy. How would a brain form spontaneously without those random fluctuations tearing the constituent components apart? I’m having trouble understanding the logic here. Random fluctuations don’t imply that any order from those fluctuations can be preserved. The higher order features like brains are path dependent on something resisting those random fluctuations to allow something stable to form, whether that’s an atomic particle, cell, organ, or organism. IANAP and I don’t know what I’m talking about

quantadev 2y ago
It's about quantum mechanics and the fact that "empty space" is not really empty. Particles do pop into existence (from nothing), according to QM, so there's a non-zero probability for any "pattern" to pop into existence. Sort of like if you have an infinite number of coin flips then at some place and time you'll land on heads a million times in a row, no matter how unlikely. And for any million-bit sequence you're guaranteed to hit it too. So a human "brain" is just a pattern that's likewise guaranteed to be "encountered". A similar concept is how the first replicator RNA/DNA got created as the beginning of life. If RNA can exist in large numbers of random sequences, then a sequence that can replicate itself only has to "happen" once and then life is started and will never slow down but will grow in complexity, as long as the environment can support it.
- throwup238 2y ago
  I get the part about popping into existence but how would even so much as a bilipid layer around a single cell form, let alone a whole brain? Where are all the antiparticles in this, except shooting around? Even if all the particles pop into existence perfectly placed for a single quanta of Plank time, aren’t the antiparticles destructively interfering with all the other particles even before they begin to annihilate? I imagine they would prevent any chemical reaction happening at all at that density. What about all the force carriers? Can they even pop into existence in the quantum foam coupled? It wouldn’t really resemble a brain in biological sense of the world because the only stimuli it can and will react to is its own disintegration. It’s hard to justify it even “existing” at all. A “virtual” brain in the sense of virtual particles perhaps, except it seems quantitatively useless.

quantadev 2y ago

The "Big Bang" theory (BBT) is equally as absurd as the Boltzmann brain conjecture, and recent evidence from the James Webb Space Telescope provides even more evidence against the BBT, by showing there are too many mature universes near the theorized "beginning of time" and also the Hubble expansion is off by 8%. I think there's more and more evidence that we're instead in a 3D reality that's the manifold (surface) of an Event Horizon. We're neither inside nor outside a black hole, but on the boundary of one. All Black Holes form from matter "falling in" rather than stuff "exploding out", and that's how our universe formed (as a Black Hole, one dimension higher up than normal 2D black holes we see). The general rule is that any N-dimensional reality is on an Event Horizon and will have contained/embedded within it (N-1)-dimensional other black holes (it's a hierarchy). The JWT also just showed our universe is expanding at a rate that's also inconsistent with our current Big Bang theory, and is off by a whopping 8%. I think the reason we see the expansion is not because of Dark Energy (which likely doesn't even exist), but is because the surface of all Event Horizons only expands over time, or in the case of a 3D (excluding time dimension) Universe we see more and more of volumetric space forming, because it's a volumetric expansion for us, rather than the "area" (2d) expansion on conventional 2D Black Holes. I also think the surface normal vector (perpendicular) vector, at any point on such a manifold (Event Horizon) will be experienced as a "time" dimension. That's why time is a "special" variable. Thus time only moves forward whenever the event horizon "grows" (due to matter falling in from outside it)

post-it 2y ago
You can always rely on HN to produce a software guy with a unique hypothesis about how the universe and/or the economy actually works.
- quantadev 2y ago
  I've been convinced of this theory for about 10 years. I don't know why people can't wrap their heads around a 3D version of the Holographic Principle (as opposed to the standard 2D version of it, per Susskind, etc.), or indeed an N-dimensional-manifold version of it. This guy did tho... (he gets into the good part right at about halfway thru) https://www.youtube.com/watch?v=A8bBhkhZtd8 https://www.youtube.com/watch?v=A8bBhkhZtd8

khana 2y ago

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Pigalowda 2y ago

Extreme solipsism is a navel gazing Boltzmann brain. The runners up are brains in jars and simulation theory. I feel like a Boltzmann brain knowing that it’s a Boltzmann brain is too good to be true. Might as well make the god of Abraham out of entropy - if you can get a regular Boltzmann brain, why not get the most powerful Boltzmann? Maybe it will take trillions of attempts over trillions of universe births and deaths. But you only need it to work the once.

cakealert 2y ago

A snapshot of an instance of you is just a really large number. A unique transition between two instances of you (@ t and t+1) is also a large number. A slideshow of your entire life's instances is just a really really large number. All these numbers are somewhere on the number line. In fact, the slideshow of every creature is on the number line. Is anything real? Because being instantiated in matter is just another way of animating the slideshow where physics takes care of the transition function. There are unfortunately no insights to be had in this endeavor.

Balgair 2y ago

I just want to point out that the time for one to randomly appear is somewhere between 10^10^50 and 10^10^69, which is is a pretty large gap. Like the difference between the two is just 10^10^69, mostly. I'll point out here that I'm not using units. The article does, but it's not like they really mean anything at these time scales. A plank time (10^-43 s) to the age of the current universe (10^9 yr) to the lower bound for the estimated time until the heat death of the universe (10^109 yr), all of those time units just end up as rounding errors compared to the lower limit of 10^10^50. The article does not go over here the time that such a brain could last for, but given that it's quantum mumbo jumbo, we can again assume something in the times of 10^-43s to 10^109 yr. Which, again, means that such a brain can hardly be said to have ever have existed in the first place compared to the time of it's formation probability. And yes, that means our current universe is in the same 'meh, just round it off' bucket. Like, we get caught up in the minutiae of this thing's mind, it's perceptions, it's sanity, it's soul (?). But if anything the absurdist thought experiment ends as just a mirror aimed at ourselves, with the void now creeping in behind our hats. What am I? What is perception? What is time? Can any of this ever possibly matter compared to these might-as-well-be infinities? Oh God! I've put numbers up here, they are very poor estimates mostly. And then I tell you that these numbers are so huge that, very literally, nothing that will ever exist in our universe can be made to understand that far future in which this absurd quantum brain comes out of. That time ceases to have any meaning at all in this not quite so empty quantum vacuum. So, having looked into this mirror, I don't know what tell you. I'm going for a walk, enjoy the season here, hug the fam, have a coffee, laugh, run, play. The universe has spared us this moment.

Geee 2y ago

I find it weird that they consider "particles which fluctuate", but these particles are a part of the universe already. There's nothing to fluctuate when the universe doesn't exist. However, if something fluctuates somewhere eternally, then I'd say that it's possible that this random fluctuation causes a very simple computer to form which is able to update it's state based on some simple rules, which results in complexity, i.e. our universe. This way you wouldn't need complexity to pop up spontaneously, but just a simple thing which is able to simulate a complex thing.

fourthark 2y ago

> Seth Lloyd has stated, "They fail the Monty Python test: Stop that! That's too silly!"

simonh 2y ago

The problem with this is that the vast majority of such brains would be a mess. Their experience, cognition, etc would be completely incoherent. Only a teeny, tiny, minuscule fraction of them would have coherent experiences that make sense. So if the argument is we're most likely to be such brains, then we are most likely to exist in a haze of incoherence. We don't. Right now I have an experience of a coherent historic memory, intentionality, sensory experiences, all of which make sense in the instant. If I am a random Bolzmann brain none of that should be true. So we'd have to have a reason to suppose that the minuscule fraction of coherent, consistent random Bolzmann brains are more likely than the occurrence of environments that generate 'actual' brains, each of which may generate many, many such brains.

725686 2y ago

I find the idea of a Boltzmman brain ridiculous. It is impossible for a random interactions of particles form such complexity. I find Lee Cronin's assembly index a great argument against this. Complex things such as living organisms, and brains, contain as integral part of themselves time. Not just time, as in infinite time, but evolutionary time.

GoblinSlayer 2y ago
Here's a counterexample: https://kundor.github.io/Finding-Waldo/ https://kundor.github.io/Finding-Waldo/
- 725686 2y ago
  No it is not. A bunch of pixels that form an image has nothing to do with stuff that was generated by evolution. Brains don't get assembled just by pushing together atoms or molecules at random, the evolved over eons going through a lot of intermediate stages.

NoZZz 2y ago

Oh jesus H ch. no one wants Boltzmann's brain, they would go insane.