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I find this question really fun: "Am I a Boltzmann brain, or a real human?". If there exists both a human and a Boltzmann brain with your current mental state,

I find this question really fun: "Am I a Boltzmann brain, or a real human?". If there exists both a human and a Boltzmann brain with your current mental state, then it doesn't make sense to try to answer this question with a single answer. Your line of reasoning will be identically executed in both, so your line of reasoning can't result in a single answer and be correct. Instead, one way to address the confusion about whether you're a Boltzmann brain or not, is to realize that in the case you're a Boltzmann brain, none of your thoughts or decisions matter at all. Even if you admit there's some probability that you're a Boltzmann brain, there's no use factoring it into your decision processes besides as a curiosity. Your decisions only matter in the case that you're an actual human, so that's the only possibility worth considering while coming up with decisions. (Similarly, if a coin was going to be flipped in a moment, and a bunch of things depended on which way the coin landed, including that you were going to be immediately executed with no possibility of escape if the coin landed on heads, then all your plans for the future should be exactly the same as if you expected the coin to land on tails with 100% certainty. It's the only path that any of your decisions matter.)

cma 7y ago
A Boltzman half-brain with random fluctuations filling in the missing hemisphere's activations is much more thermodynamically likely than a full Boltzman brain. And a quarter of one even more so, etc.
- czep 7y ago
  That certainly explains why I'm so forgetful.
jdkee 7y ago
What if you are a recurring sequence of Boltzmann brains pooping into existence, lasting mere seconds but correctly temporally sequenced as to form a continuous consciousness?
- klodolph 7y ago
  If you like these thought experiments, consider that I’m not actually responding to your comment, but I am actually mashing the keys randomly and it only appears to form a response by coincidence. We are not actually communicating with each other.
  - dsr_ 7y ago
    You are not mashing the keys, because nothing happens except that God wills it so. It just happens that God keeps making miracles that you have interpreted as the effects of your actions on the world.
    - dsr_ 7y ago
      This is the first time I've been downvoted for paraphrasing David Hume :) https://en.wikipedia.org/wiki/David_Hume https://en.wikipedia.org/wiki/David_Hume
- kelnos 7y ago
  That's not necessary (and is even less likely): the "you" at any given instant would be a Boltzmann brain with the memory of existing at previous instants.
- fredsanford 7y ago
  >> recurring sequence of Boltzmann brains pooping into existence I think this finally explains current pop music to me. Justin Beibers pooping into existence...
- AgentME 7y ago
  There's no reason to expect that your decisions would affect the next Boltzmann brain in the sequence, so there's still no need to put value of the Boltzmann brains' decisions. I don't think it makes sense to put more weight on the specific series of Boltzmann brains where the decisions seem to be followed by a subsequent Boltzmann brain than on the much more likely series of Boltzmann brains that just resemble your mental state but don't have any seemingly-causal relationships between each other. If you're allowed to put more weight on specific extremely-improbable sequences of Boltzmann brains, then you can propose all sorts of nonsense scenarios like "Imagine the series of Boltzmann brains where if one thinks of a purple elephant, then the next Boltzmann brain experiences the subsequent thought but also a lot of pain. Should you avoid thinking of purple elephants because of the fact this unordered sequence will happen eventually in an infinite universe?". I think in order to really reason about this sort of thing, you need to start considering theories of the universe like UDASSA (https://news.ycombinator.com/item?id=20119513 https://news.ycombinator.com/item?id=20119513, http://fennetic.net/irc/finney.org/~hal/udassa/ http://fennetic.net/irc/finney.org/~hal/udassa/), which provides a framework for how we should expect to anticipate different events, and Boltzmann brains and especially specifically-selected sequences of Boltzmann brains have so little measure compared to other things including our human selves that they're not worth considering, even if their decisions actually did have a causal effect on some part of a world (which would also have minuscule measure compared to ours).
john111 7y ago
>Your decisions only matter in the case that you're an actual human Why do you say that decisions matter if you're a human? At least, why would decisions matter more as a human than if you're a Boltzmann brain?
- AgentME 7y ago
  I'm not using "matter" in a very deep way here. As a human, your decisions matter to yourself in the sense that you're going to experience the consequences of them. If you choose to eat an inedible object, then you're going to have a bad time. But if a Boltzmann brain chooses to eat an inedible object, it does not matter because the Boltzmann brain can't execute that decision in reality and is going to stop existing in a moment.
  - deleted 7y ago
    [deleted]
  - officialjunk 7y ago
    in the sense that we could be "brains in boxes" like in the matrix, one could argue that this reality we experience could happen to a boltzmann brain as well. similar to a dream, in which the dream reality is a result of feeding all the senses with data from within.
    - dahfizz 7y ago
      An important distinction is that a boltzman brain only "works" for an instant before the harsh environment of space destroys it. There's simply no time for a whole dream matrix reality to play out.
      - quakeguy 7y ago
        Why? The time passed for the Boltzmann Brain won’t necessarily be tied to its real frame of existence i think, it may simulate any timeframe imaginable, depending on its starting conditions.
Quekid5 7y ago
Yes. You're a Boltzmann brain. Now what? a) You have no choice in the matter, and b) You can't change your reality anyway, so... why rebel? (I observe that point b is predicated on the abject failure of a... in which case why was the everloving f. of everybody privvy to his non-detailed-death. Secrets ppl? WTF IS WHAT?)
- KerrickStaley 7y ago
  I don't understand the point you're trying to make in this post.
  - Quekid5 7y ago
    Yeah, I kind of went off the rails there, didn't I? My point was merely: How do you recgocnize a brain (and its very special cousisn the BB) at all? I wager it's just because you see a human before you. But if you really want to question things... then you're in for a very bleak time.
    - blurps 7y ago
      Just like one can't disprove solipsism, one can only brush it aside as pragmatically useless. Just because a theory is internally consistent or even accurate, does not mean it is a good all-around theory: simplicity and elegance counts too. And having to agree on who is the solipsist among all figments is inelegant and an impossibly complex task. > According to the most extreme form of this view the only way by which one could be sure that a machine thinks is to be the machine and to feel oneself thinking. One could then describe these feelings to the world, but of course no one would be justified in taking any notice. Likewise according to this view the only way to know that a man thinks is to be that particular man. It is in fact the solipsist point of view. It may be the most logical view to hold but it makes communication of ideas difficult. A is liable to believe ‘A thinks but B does not’ whilst B believes ‘B thinks but A does not’. Instead of arguing continually over this point it is usual to have the polite convention that everyone thinks. -- Alan Turing
      - 7y ago
draw_down 7y ago
This was my big problem with the western philosophy classes I took in college. It’s a bunch of Descartes staring at a candle, saying, am I real? Is this candle real? It doesn’t matter because if the answer is no there is nothing to be done about it.
petters 7y ago
But if you are a Boltzmann brain (Bb), it would be a very big coincidence if all of your memories were internally consistent. Since they presumably mostly are, you are likely not a Bb.
- lacker 7y ago
  That conclusion isn’t quite logically rigorous. You need to have a prior on the odds of being a Boltzmann brain in the first place. If that prior is extremely high, your conclusion won’t hold.
- ken 7y ago
  You can hide a lot behind "presumably mostly"! My memories aren't entirely internally consistent. Memories fade over time, too, so even if they formed perfectly, I certainly misremember many events. The earliest ones are from when I was a kid, when I didn't understand the world, so I naturally place the least faith in their accuracy. When I do have conflicting memories, I use logic and common sense to try to figure out which is correct, and hedge my bets against memories which might be false. So if I were an intelligent brain formed with random memories, over time my natural tendency, in order to remain sane, would be to correct my memories to be internally consistent, as much as needed, and not examine the rest too closely.
cgriswald 7y ago
I think the proof that I am not a Boltzmann Brain is that my memories are chronological and all feature me as the self. If it is infinitely more likely that I am a Boltzmann Brain than not, isn’t it also extremely more likely that I’d be one with any number of random memories rather than a group of memories that form a more or less coherent whole?
- NobodyNada 7y ago
  A dream is a totally incoherent result of random fluctuations, but it seems real and coherent until you wake up. A Boltzmann brain only exists for a very short period of time — on that small of a timescale, your existence is really just a single instantaneous snapshot of a state of mind, and there’s no time to recall a sequence of memories or think through logical propositions. Even though existence feels coherent, that feeling would be just a false memory.
  - glenstein 7y ago
    I would disagree that a dream is 'totally' incoherent or truly random, and I don't think it's necessarily inevitable that existence would feel coherent, which I take to be GP's point. There's a wide swath of possible sets of memories I could be given. Some coherent and belonging to a self. Some that seem to but that, given sufficient relfection, would turn out not to be, as when you wake up from a dream, and then some that, even when lucidly regarded in the moment appear to be nonsensical on their face. Of this range of possibilities, ones giving you a seemingly coherent and ordered timeline of experiences, or one that is disordered but close enough to order that it can be readily can be interpreted as ordered, would appear to be more improbable. >on that small of a timescale, your existence is really just a single instantaneous snapshot of a state of mind, and there’s no time to recall a sequence of memories or think through logical propositions. I think this is very true. Even being around long enough to pose the question to yourself gives you reasonably strong confidence that you've 'tested out' of being a boltzman brain. Though I think that consideration is being momentarily set aside for purposes of this variant of the thought experiment.
  - misterman0 7y ago
Thorrez 7y ago
It's very easy to tell you're not a Boltzmann brain. As long as your consciousness lasts more than a few seconds, you're not a Boltzmann brain. A Bolzmann brain appears in the vacuum of space and will quickly die due to the vacuum and not being in a body. > Typically, a quantum Boltzmann brain would suddenly appear from the vacuum (alongside an equivalent amount of virtual antimatter), remain only long enough to have a single coherent thought or observation, and then disappear into the vacuum as suddenly as it appeared.
- OscarCunningham 7y ago
  But at any given moment you don't know if your consciousness has lasted more than a few seconds or if you've just appeared with the false memories of having been conscious for a long time.
  - rezmason 7y ago
    It begs the question, how few "true" memories and perceptions does consciousness require? I don't know 5^4, but I know I can know it; but couldn't my knowledge of all math be a false memory as well? Could a consciousness comprise of just a single, false perception— that there are further memories and perceptions? What would it take for such a "mind" to manifest in our universe? Probably almost nothing; I can't imagine the difference between this and an inert object, or even an instantaneous event. It has no real memory, so it doesn't need to exist for more than an instant. (Uh, you can stop reading here if you want. Just a warning.) This has some parallels to Bill Gosper's "HashLife", an implementation of Conway's Game of Life that effectively hashes every event at every scale and timescale. The simulation accelerates rapidly by skipping events whose cause and effect are already coded into those of larger events, and so on, up and up and up; every portion of the simulation ends up being a key for a value in the cosmic hash table. So who's to say what in the simulation is real, and what is symbolic of something more complex?
namanyayg 7y ago
Almost all commenters below here seem to be stuck with how insufficient appearing like a continuous stream of consciousness is. It's a dhamma, impermenant, easily fakeable.
kromem 7y ago
It's also interesting to consider other Boltzmann "objects" as well. In theory, just as it can be argued that it'd be more thermodynamically probable that a single brain would occur than an entire universe - what about a single quantum computer running a simulation of such a universe? But why even necessitate the physical at all? Could there simply be a Boltzmann simulation - a collection of abstract information and rules representing a multi-dimensional physical universe? In particular, if it contained techniques internally similar to procedural generation, a great deal of abstracted information could be represented by a much more compact collection of algorithms and rules. Of course, some might even take the concept further, reducing from a Boltzmann simulation to simply a Boltzmann architect - a purely information based intelligence capable of creating and sustaining such a simulation without the need of any physicality at all, and spawning off child threads to extend that property of "consciousness." Such a foundational basis for existence (in either the ontological spontaneous simulation or intelligent designer cases) might both be argued to be more likely to occur than the massive physical universe itself.
- AgentME 7y ago
  The book Permutation City explores a concept like this. I really recommend it.
- glenstein 7y ago
  This is all really awesome from my perspective, but I kiiinda got lost about here: >Of course, some might even take the concept further, reducing from a Boltzmann simulation to simply a Boltzmann architect - a purely information based intelligence capable of creating and sustaining such a simulation without the need of any physicality at all, and spawning off child threads to extend that property of "consciousness." I guess the concept of 'pure information' or 'abstracted information' is where I start to get confused. You'd still need that instantiated on some physical medium. A bunch of hydrogen atoms (or whatever) would have to jostle into place to represent the needed information, right? Unless this is a variant of a Kalam cosmological argument that takes minds to be different from, and simpler than, physical things? Or is this non-physical 'stuff', and if so, does that non-physical stuff get subjected to the random jostling the same way as physical stuff? >and sustaining such a simulation without the need of any physicality at all, and spawning off child threads to extend that property of "consciousness." And where are we here? I'm not clear what physical medium the intelligence/simulation/pure information is on, or if there's no physical medium, I'm not clear on what way the intelligence/simulation/pure information is popping into existence or what it means to spawn child threads. Maybe for your purposes physicalism is entirely assumed away at this point? Then there's the 'foundational basis for existence' which I think departs from the terms of the original thought experiment, which presupposes that a certain kind of universe already got there, and that Boltzmann Objects are already busy poofing into and out of existence within it. Though I take your more general points that (1) there's a whooole taxonomy of Boltzmann "objects" that can be imagined and (2) among those objects, some of them will be relatively simple and make for interesting considerations about what's most likely to poof into existence.
glenstein 7y ago
>I find this question really fun: "Am I a Boltzmann brain, or a real human?". If there exists both a human and a Boltzmann brain with your current mental state, then it doesn't make sense to try to answer this question with a single answer. While probably not entirely in the spirit of your question, I would emphasize this part of the wiki article: >Like any brain in such circumstances, it would almost immediately stop functioning and begin to deteriorate. I think if you pause long enough to consider whether you're a Boltzmann brain, you've probably lasted longer than one and aren't one.
- joshuaissac 7y ago
  A Boltzmann brain can form with a false memory that it had paused to consider whether it is a Boltzmann brain. In other words, take a real human considering whether they are a Boltzmann brain and deciding that they are not. Any single moment in that human's existence can be simulated by a Boltzmann brain existing momentarily, including the moment where the human concludes that they are a real human, and the moment where the human reflects on its conclusion that it is not a Boltzmann brain.
  - glenstein 7y ago
    You're right. It can, and I see this has been discussed elsewhere in the thread. So it's certainly in play. But each variant of a boltzman brain that accounts for the passage of time, passes that 'test' at the cost of being less probable overall. Most boltzman brains won't pass that test, but some will. And then you throw in the other tests people have mentioned: a feeling that your memories are somehow internally coherent and consistent. Most won't pass that test either, but some will. And 'some' could be so many that, if you were picking out of a hat, they are still more likely than that your experiences have really happened. I guess the interesting question is whether you can collect together enough 'tests' that filter out BBs, that you can pare down the range of possible BBs that pass the tests, to the point that they become a less probable explanation than the actual spontaneous emergence of life in the universe.
    - lonelappde 7y ago
pattisapu 7y ago
The shape of this argument reminds me of Pascal's wager.

cma 7y ago

A Boltzman half-brain with random fluctuations filling in the missing hemisphere's activations is much more thermodynamically likely than a full Boltzman brain. And a quarter of one even more so, etc.

czep 7y ago
That certainly explains why I'm so forgetful.

jdkee 7y ago

What if you are a recurring sequence of Boltzmann brains pooping into existence, lasting mere seconds but correctly temporally sequenced as to form a continuous consciousness?

klodolph 7y ago
If you like these thought experiments, consider that I’m not actually responding to your comment, but I am actually mashing the keys randomly and it only appears to form a response by coincidence. We are not actually communicating with each other.
- dsr_ 7y ago
  You are not mashing the keys, because nothing happens except that God wills it so. It just happens that God keeps making miracles that you have interpreted as the effects of your actions on the world.
  - dsr_ 7y ago
    This is the first time I've been downvoted for paraphrasing David Hume :) https://en.wikipedia.org/wiki/David_Hume https://en.wikipedia.org/wiki/David_Hume
kelnos 7y ago
That's not necessary (and is even less likely): the "you" at any given instant would be a Boltzmann brain with the memory of existing at previous instants.
fredsanford 7y ago
>> recurring sequence of Boltzmann brains pooping into existence I think this finally explains current pop music to me. Justin Beibers pooping into existence...
AgentME 7y ago
There's no reason to expect that your decisions would affect the next Boltzmann brain in the sequence, so there's still no need to put value of the Boltzmann brains' decisions. I don't think it makes sense to put more weight on the specific series of Boltzmann brains where the decisions seem to be followed by a subsequent Boltzmann brain than on the much more likely series of Boltzmann brains that just resemble your mental state but don't have any seemingly-causal relationships between each other. If you're allowed to put more weight on specific extremely-improbable sequences of Boltzmann brains, then you can propose all sorts of nonsense scenarios like "Imagine the series of Boltzmann brains where if one thinks of a purple elephant, then the next Boltzmann brain experiences the subsequent thought but also a lot of pain. Should you avoid thinking of purple elephants because of the fact this unordered sequence will happen eventually in an infinite universe?". I think in order to really reason about this sort of thing, you need to start considering theories of the universe like UDASSA (https://news.ycombinator.com/item?id=20119513 https://news.ycombinator.com/item?id=20119513, http://fennetic.net/irc/finney.org/~hal/udassa/ http://fennetic.net/irc/finney.org/~hal/udassa/), which provides a framework for how we should expect to anticipate different events, and Boltzmann brains and especially specifically-selected sequences of Boltzmann brains have so little measure compared to other things including our human selves that they're not worth considering, even if their decisions actually did have a causal effect on some part of a world (which would also have minuscule measure compared to ours).

john111 7y ago

>Your decisions only matter in the case that you're an actual human Why do you say that decisions matter if you're a human? At least, why would decisions matter more as a human than if you're a Boltzmann brain?

AgentME 7y ago
I'm not using "matter" in a very deep way here. As a human, your decisions matter to yourself in the sense that you're going to experience the consequences of them. If you choose to eat an inedible object, then you're going to have a bad time. But if a Boltzmann brain chooses to eat an inedible object, it does not matter because the Boltzmann brain can't execute that decision in reality and is going to stop existing in a moment.
- deleted 7y ago
  [deleted]
- officialjunk 7y ago
  in the sense that we could be "brains in boxes" like in the matrix, one could argue that this reality we experience could happen to a boltzmann brain as well. similar to a dream, in which the dream reality is a result of feeding all the senses with data from within.
  - dahfizz 7y ago
    An important distinction is that a boltzman brain only "works" for an instant before the harsh environment of space destroys it. There's simply no time for a whole dream matrix reality to play out.
    - quakeguy 7y ago
      Why? The time passed for the Boltzmann Brain won’t necessarily be tied to its real frame of existence i think, it may simulate any timeframe imaginable, depending on its starting conditions.

Quekid5 7y ago

Yes. You're a Boltzmann brain. Now what? a) You have no choice in the matter, and b) You can't change your reality anyway, so... why rebel? (I observe that point b is predicated on the abject failure of a... in which case why was the everloving f. of everybody privvy to his non-detailed-death. Secrets ppl? WTF IS WHAT?)

KerrickStaley 7y ago
I don't understand the point you're trying to make in this post.
- Quekid5 7y ago
  Yeah, I kind of went off the rails there, didn't I? My point was merely: How do you recgocnize a brain (and its very special cousisn the BB) at all? I wager it's just because you see a human before you. But if you really want to question things... then you're in for a very bleak time.
  - blurps 7y ago
    Just like one can't disprove solipsism, one can only brush it aside as pragmatically useless. Just because a theory is internally consistent or even accurate, does not mean it is a good all-around theory: simplicity and elegance counts too. And having to agree on who is the solipsist among all figments is inelegant and an impossibly complex task. > According to the most extreme form of this view the only way by which one could be sure that a machine thinks is to be the machine and to feel oneself thinking. One could then describe these feelings to the world, but of course no one would be justified in taking any notice. Likewise according to this view the only way to know that a man thinks is to be that particular man. It is in fact the solipsist point of view. It may be the most logical view to hold but it makes communication of ideas difficult. A is liable to believe ‘A thinks but B does not’ whilst B believes ‘B thinks but A does not’. Instead of arguing continually over this point it is usual to have the polite convention that everyone thinks. -- Alan Turing
    - 7y ago

draw_down 7y ago

This was my big problem with the western philosophy classes I took in college. It’s a bunch of Descartes staring at a candle, saying, am I real? Is this candle real? It doesn’t matter because if the answer is no there is nothing to be done about it.

petters 7y ago

But if you are a Boltzmann brain (Bb), it would be a very big coincidence if all of your memories were internally consistent. Since they presumably mostly are, you are likely not a Bb.

lacker 7y ago
That conclusion isn’t quite logically rigorous. You need to have a prior on the odds of being a Boltzmann brain in the first place. If that prior is extremely high, your conclusion won’t hold.
ken 7y ago
You can hide a lot behind "presumably mostly"! My memories aren't entirely internally consistent. Memories fade over time, too, so even if they formed perfectly, I certainly misremember many events. The earliest ones are from when I was a kid, when I didn't understand the world, so I naturally place the least faith in their accuracy. When I do have conflicting memories, I use logic and common sense to try to figure out which is correct, and hedge my bets against memories which might be false. So if I were an intelligent brain formed with random memories, over time my natural tendency, in order to remain sane, would be to correct my memories to be internally consistent, as much as needed, and not examine the rest too closely.

cgriswald 7y ago

I think the proof that I am not a Boltzmann Brain is that my memories are chronological and all feature me as the self. If it is infinitely more likely that I am a Boltzmann Brain than not, isn’t it also extremely more likely that I’d be one with any number of random memories rather than a group of memories that form a more or less coherent whole?

NobodyNada 7y ago
A dream is a totally incoherent result of random fluctuations, but it seems real and coherent until you wake up. A Boltzmann brain only exists for a very short period of time — on that small of a timescale, your existence is really just a single instantaneous snapshot of a state of mind, and there’s no time to recall a sequence of memories or think through logical propositions. Even though existence feels coherent, that feeling would be just a false memory.
- glenstein 7y ago
  I would disagree that a dream is 'totally' incoherent or truly random, and I don't think it's necessarily inevitable that existence would feel coherent, which I take to be GP's point. There's a wide swath of possible sets of memories I could be given. Some coherent and belonging to a self. Some that seem to but that, given sufficient relfection, would turn out not to be, as when you wake up from a dream, and then some that, even when lucidly regarded in the moment appear to be nonsensical on their face. Of this range of possibilities, ones giving you a seemingly coherent and ordered timeline of experiences, or one that is disordered but close enough to order that it can be readily can be interpreted as ordered, would appear to be more improbable. >on that small of a timescale, your existence is really just a single instantaneous snapshot of a state of mind, and there’s no time to recall a sequence of memories or think through logical propositions. I think this is very true. Even being around long enough to pose the question to yourself gives you reasonably strong confidence that you've 'tested out' of being a boltzman brain. Though I think that consideration is being momentarily set aside for purposes of this variant of the thought experiment.
- misterman0 7y ago

Thorrez 7y ago

It's very easy to tell you're not a Boltzmann brain. As long as your consciousness lasts more than a few seconds, you're not a Boltzmann brain. A Bolzmann brain appears in the vacuum of space and will quickly die due to the vacuum and not being in a body. > Typically, a quantum Boltzmann brain would suddenly appear from the vacuum (alongside an equivalent amount of virtual antimatter), remain only long enough to have a single coherent thought or observation, and then disappear into the vacuum as suddenly as it appeared.

OscarCunningham 7y ago
But at any given moment you don't know if your consciousness has lasted more than a few seconds or if you've just appeared with the false memories of having been conscious for a long time.
- rezmason 7y ago
  It begs the question, how few "true" memories and perceptions does consciousness require? I don't know 5^4, but I know I can know it; but couldn't my knowledge of all math be a false memory as well? Could a consciousness comprise of just a single, false perception— that there are further memories and perceptions? What would it take for such a "mind" to manifest in our universe? Probably almost nothing; I can't imagine the difference between this and an inert object, or even an instantaneous event. It has no real memory, so it doesn't need to exist for more than an instant. (Uh, you can stop reading here if you want. Just a warning.) This has some parallels to Bill Gosper's "HashLife", an implementation of Conway's Game of Life that effectively hashes every event at every scale and timescale. The simulation accelerates rapidly by skipping events whose cause and effect are already coded into those of larger events, and so on, up and up and up; every portion of the simulation ends up being a key for a value in the cosmic hash table. So who's to say what in the simulation is real, and what is symbolic of something more complex?

namanyayg 7y ago

Almost all commenters below here seem to be stuck with how insufficient appearing like a continuous stream of consciousness is. It's a dhamma, impermenant, easily fakeable.

kromem 7y ago

It's also interesting to consider other Boltzmann "objects" as well. In theory, just as it can be argued that it'd be more thermodynamically probable that a single brain would occur than an entire universe - what about a single quantum computer running a simulation of such a universe? But why even necessitate the physical at all? Could there simply be a Boltzmann simulation - a collection of abstract information and rules representing a multi-dimensional physical universe? In particular, if it contained techniques internally similar to procedural generation, a great deal of abstracted information could be represented by a much more compact collection of algorithms and rules. Of course, some might even take the concept further, reducing from a Boltzmann simulation to simply a Boltzmann architect - a purely information based intelligence capable of creating and sustaining such a simulation without the need of any physicality at all, and spawning off child threads to extend that property of "consciousness." Such a foundational basis for existence (in either the ontological spontaneous simulation or intelligent designer cases) might both be argued to be more likely to occur than the massive physical universe itself.

AgentME 7y ago
The book Permutation City explores a concept like this. I really recommend it.
glenstein 7y ago
This is all really awesome from my perspective, but I kiiinda got lost about here: >Of course, some might even take the concept further, reducing from a Boltzmann simulation to simply a Boltzmann architect - a purely information based intelligence capable of creating and sustaining such a simulation without the need of any physicality at all, and spawning off child threads to extend that property of "consciousness." I guess the concept of 'pure information' or 'abstracted information' is where I start to get confused. You'd still need that instantiated on some physical medium. A bunch of hydrogen atoms (or whatever) would have to jostle into place to represent the needed information, right? Unless this is a variant of a Kalam cosmological argument that takes minds to be different from, and simpler than, physical things? Or is this non-physical 'stuff', and if so, does that non-physical stuff get subjected to the random jostling the same way as physical stuff? >and sustaining such a simulation without the need of any physicality at all, and spawning off child threads to extend that property of "consciousness." And where are we here? I'm not clear what physical medium the intelligence/simulation/pure information is on, or if there's no physical medium, I'm not clear on what way the intelligence/simulation/pure information is popping into existence or what it means to spawn child threads. Maybe for your purposes physicalism is entirely assumed away at this point? Then there's the 'foundational basis for existence' which I think departs from the terms of the original thought experiment, which presupposes that a certain kind of universe already got there, and that Boltzmann Objects are already busy poofing into and out of existence within it. Though I take your more general points that (1) there's a whooole taxonomy of Boltzmann "objects" that can be imagined and (2) among those objects, some of them will be relatively simple and make for interesting considerations about what's most likely to poof into existence.

glenstein 7y ago

>I find this question really fun: "Am I a Boltzmann brain, or a real human?". If there exists both a human and a Boltzmann brain with your current mental state, then it doesn't make sense to try to answer this question with a single answer. While probably not entirely in the spirit of your question, I would emphasize this part of the wiki article: >Like any brain in such circumstances, it would almost immediately stop functioning and begin to deteriorate. I think if you pause long enough to consider whether you're a Boltzmann brain, you've probably lasted longer than one and aren't one.

joshuaissac 7y ago
A Boltzmann brain can form with a false memory that it had paused to consider whether it is a Boltzmann brain. In other words, take a real human considering whether they are a Boltzmann brain and deciding that they are not. Any single moment in that human's existence can be simulated by a Boltzmann brain existing momentarily, including the moment where the human concludes that they are a real human, and the moment where the human reflects on its conclusion that it is not a Boltzmann brain.
- glenstein 7y ago
  You're right. It can, and I see this has been discussed elsewhere in the thread. So it's certainly in play. But each variant of a boltzman brain that accounts for the passage of time, passes that 'test' at the cost of being less probable overall. Most boltzman brains won't pass that test, but some will. And then you throw in the other tests people have mentioned: a feeling that your memories are somehow internally coherent and consistent. Most won't pass that test either, but some will. And 'some' could be so many that, if you were picking out of a hat, they are still more likely than that your experiences have really happened. I guess the interesting question is whether you can collect together enough 'tests' that filter out BBs, that you can pare down the range of possible BBs that pass the tests, to the point that they become a less probable explanation than the actual spontaneous emergence of life in the universe.
  - lonelappde 7y ago

pattisapu 7y ago

The shape of this argument reminds me of Pascal's wager.