13 ms·

Even more "mind shivering" than this one was a linked article about Boltzman brains (http://en.wikipedia.org/wiki/Boltzmann_brain http://en.wikipedia.org/wiki/B

by kghose 14y ago

Even more "mind shivering" than this one was a linked article about Boltzman brains (http://en.wikipedia.org/wiki/Boltzmann_brain http://en.wikipedia.org/wiki/Boltzmann_brain) which I had never heard of before.

kartman 14y ago
Fascinating, wonder if this can be generalized to - for any local state that has observably occured, its subset will likely occur some where in the universe.
aneth 14y ago
What's more likely: nearly infinite sentient universes complete with false memories of human experiences emerging from entropic chaos, or that we don't quite understand the nature of entropy? The Boltzmann theory is one of those thought experiments that should draw into question it's assumptions out of the pure absurdity of its logical conclusions rather than be taken seriously itself.
- eliben 14y ago
  Isn't this just a simple matter of probability? Given an event, however unprobable it is, it can happen given infinite time? From a purely mathematical standpoint, this is correct.
  - aneth 14y ago
    If your assumption is infinite time and complete entropy, yes it's correct. It's also why some level of common sense (e.g. Occam's razor) should be applied before such silliness is seriously proposed. I don't think Boltzmann assumes infinite time and entropy, just enough for the completely random emergence of sentient life that thinks (perhaps falsely) that it lives in a universe populated by similar beings who created iPads from dirt and water. Does it seem more reasonable that there is infinite time and every possible state of matter and history exists at some point, or that we simply haven't figured out the balancing forces of entropy and order? Infinity is an interesting thought experiment, but it so thoroughly ridiculous that it should cause us to question our assumptions, not believe in absurdity conclusions based on faith in mathematics and unproven postulates that got us there. We might as well believe the Bible is true. Not only is it less absurd, but given the infinite theory, there must exist a universe where it is true, and this could be it (unless it is truly contradictory and impossible even with infinite states of the universe, which we have no reason to believe.)
    - d0mine 14y ago
      To use Occam's razor you need a competing simpler (less assumptions) theory. "Common sense" might be a tool to produce such a theory but it is not a theory by itself.
    - JoachimSchipper 14y ago
      Implying that the Bible is "absurd" does not help the discussion and makes believers feel unwelcome. Please be nice. (I'm an atheist.)
      - aneth 14y ago
        The Bible as historical non-fiction is most certainly absurd, no implications about that. Not saying so out of sensitivity to those who believe otherwise does reason a disservice, just as not calling out Bolzmann because I don't want to offend him. If this makes anyone unwelcome, they should avoid places where their fragile ego might be challenged by rational conclusions. In a place like hacker news, I see no reason to let sensistivity toward faith restrict my speech any more than sensitivity toward programming language choice. Invite me for dinner and I will respect your religious and any other beliefs. Have a scientific debate in a web forum with me, and I will speak without concern for challenging you. It's not a personal attack to say the Bible is absurd - it's the truth.
        JoachimSchipper 14y ago
        By the same standard, "SOPA sucks. Just like PHP/Java." is appropriate. "PHP/Java sucks" may be appropriate when discussing programming languages, but dragging it into a thread about SOPA does not help.
        aneth 14y ago
        I'm not sure I understand your point. "SOPA sucks. Just like PHP/Java" is a useless statement, since the only thing the two have in common is "sucking." The Bible is an alternative theory of the origin and purpose of existence, and is directly analogous to the matter of this thread.
  - possibilistic 14y ago
    Just because something has a nonzero probability doesn't mean it will ever occur. Entropy is just dS = dQ/T. It's simply a thermodynamic property that measures where system energy is. All of these grand notions extrapolated from thermodynamics are crazy. Thermodynamics is/was just a first approach at studying macroscale systems because we didn't yet grasp the underlying quantum behavior. It's incredibly useful when applied to chemical and physical problems, but you can't use it to make wild claims like this.
    - Symmetry 14y ago
      Its certainly possible that the universe will end in a crunch or a rip, and all this speculation will be for naught. But thermodynaics is still a perfectly valid way of looking at these things, and hasn't been changed much by the addition of quantum mechanics except that we now talk about probability distributions within phase space instead of points. Its basically the same stuff, with the same consequences. Entropy is much more than just dS = dQ/T. I mean, that equation is mostly valid the same way that Newton's laws are mostly valid, but you won't be able to get any sort of feel for it approaching the subject that way. Imagine a mathmatical space with six dimensions for every particle, three for position and three for momentum. The state of the universe is a single point moving in this space according to pre-defined rules. Now, we don't know which point or microstate corresponds to our universe, because we can only make crude measurements of statistical aggregates of particles like temperature and pressure and so forth. So by making these measurements we can narrow which universe we're in to a set of these microstates, a 6N-k dimensional region of the 6N dimensional space that we'll call a macrostate. The entropy of an observed macrostate is proportional to the log of the number of microstates that a macrostate contains, S = k log W. In a sense, Entropy is a measure of our ignorance of which universe we're in, which is ultimately why Maxwell's demon doesn't work. Please note, the above does contain simplifying assumptions which don't change the main point. For the full story, go get a physics minor at a good university or start reading Wikipedia[1] and asking your physics major friends questions until you can re-derive the laws of thermodynamics yourself. [1]http://en.wikipedia.org/wiki/Statistical_thermodynamics http://en.wikipedia.org/wiki/Statistical_thermodynamics
- majmun 14y ago
  Error in Boltzman brains theory is that he assumes that universe with brains randomly fluctuated into existance into its current form , and concludes that this form is more complex than just brain and therefore brains without environments are more common (maybe iPhones or Bible are even more common then), and assumes that brain can exist without environment. also second law of thermodynamics states that resulting entropy would never be decreased. and doesnt tells us about entrophy dynamics in intermediate steps.
  - torstesu 14y ago
    So... what your saying is that my master thesis won't write itself by some random fluctuations after all? I might have to alter my strategy.
    - zmj 14y ago
      Sure it will. You might have to turn it in late, though.
  - Symmetry 14y ago
    iPhones or Bibles probably are more common. And an isolated brain without an environment really is much more likely than a brain and body and environment, at least if we're talking about random fluctuations rather than structures created as a consequence of the the availability of useful energy in the environment. If you think about it in terms of the Canonical Ensemble the regions of states that correspond to "a brain and body" are obviously a small subset of the regions that correspond to "a brain". The incompressability of phase space means that this translates directly to the world being less likely to wander into those smaller regions via random fluctuations in direct proportion to their size. In the end, the second law of thermodynamics is only a (very strong) statistical likelihood. If you mix some salt water and fresh water, then wait long enough you'll eventually find all the salt in one side of the glass (in time proportional to 2^N where N is the number of salt ions). Its not something written into the fabric of the universe directly, but a consequence of more fundamental laws and if you take Statistical Mechanics in college you'll get to re-derive it and see why it works that way. In fact, I'd really recommend taking a Stat Mech class to anyone considering it, it was probably the most interesting class I took in college.
jamesjyu 14y ago
Thanks for sending me down hours of engrossed reading in which I constantly question the nature of my existence.
Devilboy 14y ago
We are Boltzman brains, no?
- paol 14y ago
  No, I'm a Boltzmann brain. The rest of you are just a figment of my imagination.
Symmetry 14y ago
The idea of Boltzman brains is a good reason to hope that the universe ends with a big crunch.

by kghose 14y ago

kartman 14y ago

Fascinating, wonder if this can be generalized to - for any local state that has observably occured, its subset will likely occur some where in the universe.

aneth 14y ago

What's more likely: nearly infinite sentient universes complete with false memories of human experiences emerging from entropic chaos, or that we don't quite understand the nature of entropy? The Boltzmann theory is one of those thought experiments that should draw into question it's assumptions out of the pure absurdity of its logical conclusions rather than be taken seriously itself.

eliben 14y ago
Isn't this just a simple matter of probability? Given an event, however unprobable it is, it can happen given infinite time? From a purely mathematical standpoint, this is correct.
- aneth 14y ago
  If your assumption is infinite time and complete entropy, yes it's correct. It's also why some level of common sense (e.g. Occam's razor) should be applied before such silliness is seriously proposed. I don't think Boltzmann assumes infinite time and entropy, just enough for the completely random emergence of sentient life that thinks (perhaps falsely) that it lives in a universe populated by similar beings who created iPads from dirt and water. Does it seem more reasonable that there is infinite time and every possible state of matter and history exists at some point, or that we simply haven't figured out the balancing forces of entropy and order? Infinity is an interesting thought experiment, but it so thoroughly ridiculous that it should cause us to question our assumptions, not believe in absurdity conclusions based on faith in mathematics and unproven postulates that got us there. We might as well believe the Bible is true. Not only is it less absurd, but given the infinite theory, there must exist a universe where it is true, and this could be it (unless it is truly contradictory and impossible even with infinite states of the universe, which we have no reason to believe.)
  - d0mine 14y ago
    To use Occam's razor you need a competing simpler (less assumptions) theory. "Common sense" might be a tool to produce such a theory but it is not a theory by itself.
  - JoachimSchipper 14y ago
    Implying that the Bible is "absurd" does not help the discussion and makes believers feel unwelcome. Please be nice. (I'm an atheist.)
    - aneth 14y ago
      The Bible as historical non-fiction is most certainly absurd, no implications about that. Not saying so out of sensitivity to those who believe otherwise does reason a disservice, just as not calling out Bolzmann because I don't want to offend him. If this makes anyone unwelcome, they should avoid places where their fragile ego might be challenged by rational conclusions. In a place like hacker news, I see no reason to let sensistivity toward faith restrict my speech any more than sensitivity toward programming language choice. Invite me for dinner and I will respect your religious and any other beliefs. Have a scientific debate in a web forum with me, and I will speak without concern for challenging you. It's not a personal attack to say the Bible is absurd - it's the truth.
      - JoachimSchipper 14y ago
        By the same standard, "SOPA sucks. Just like PHP/Java." is appropriate. "PHP/Java sucks" may be appropriate when discussing programming languages, but dragging it into a thread about SOPA does not help.
        aneth 14y ago
        I'm not sure I understand your point. "SOPA sucks. Just like PHP/Java" is a useless statement, since the only thing the two have in common is "sucking." The Bible is an alternative theory of the origin and purpose of existence, and is directly analogous to the matter of this thread.
- possibilistic 14y ago
  Just because something has a nonzero probability doesn't mean it will ever occur. Entropy is just dS = dQ/T. It's simply a thermodynamic property that measures where system energy is. All of these grand notions extrapolated from thermodynamics are crazy. Thermodynamics is/was just a first approach at studying macroscale systems because we didn't yet grasp the underlying quantum behavior. It's incredibly useful when applied to chemical and physical problems, but you can't use it to make wild claims like this.
  - Symmetry 14y ago
    Its certainly possible that the universe will end in a crunch or a rip, and all this speculation will be for naught. But thermodynaics is still a perfectly valid way of looking at these things, and hasn't been changed much by the addition of quantum mechanics except that we now talk about probability distributions within phase space instead of points. Its basically the same stuff, with the same consequences. Entropy is much more than just dS = dQ/T. I mean, that equation is mostly valid the same way that Newton's laws are mostly valid, but you won't be able to get any sort of feel for it approaching the subject that way. Imagine a mathmatical space with six dimensions for every particle, three for position and three for momentum. The state of the universe is a single point moving in this space according to pre-defined rules. Now, we don't know which point or microstate corresponds to our universe, because we can only make crude measurements of statistical aggregates of particles like temperature and pressure and so forth. So by making these measurements we can narrow which universe we're in to a set of these microstates, a 6N-k dimensional region of the 6N dimensional space that we'll call a macrostate. The entropy of an observed macrostate is proportional to the log of the number of microstates that a macrostate contains, S = k log W. In a sense, Entropy is a measure of our ignorance of which universe we're in, which is ultimately why Maxwell's demon doesn't work. Please note, the above does contain simplifying assumptions which don't change the main point. For the full story, go get a physics minor at a good university or start reading Wikipedia[1] and asking your physics major friends questions until you can re-derive the laws of thermodynamics yourself. [1]http://en.wikipedia.org/wiki/Statistical_thermodynamics http://en.wikipedia.org/wiki/Statistical_thermodynamics
majmun 14y ago
Error in Boltzman brains theory is that he assumes that universe with brains randomly fluctuated into existance into its current form , and concludes that this form is more complex than just brain and therefore brains without environments are more common (maybe iPhones or Bible are even more common then), and assumes that brain can exist without environment. also second law of thermodynamics states that resulting entropy would never be decreased. and doesnt tells us about entrophy dynamics in intermediate steps.
- torstesu 14y ago
  So... what your saying is that my master thesis won't write itself by some random fluctuations after all? I might have to alter my strategy.
  - zmj 14y ago
    Sure it will. You might have to turn it in late, though.
- Symmetry 14y ago
  iPhones or Bibles probably are more common. And an isolated brain without an environment really is much more likely than a brain and body and environment, at least if we're talking about random fluctuations rather than structures created as a consequence of the the availability of useful energy in the environment. If you think about it in terms of the Canonical Ensemble the regions of states that correspond to "a brain and body" are obviously a small subset of the regions that correspond to "a brain". The incompressability of phase space means that this translates directly to the world being less likely to wander into those smaller regions via random fluctuations in direct proportion to their size. In the end, the second law of thermodynamics is only a (very strong) statistical likelihood. If you mix some salt water and fresh water, then wait long enough you'll eventually find all the salt in one side of the glass (in time proportional to 2^N where N is the number of salt ions). Its not something written into the fabric of the universe directly, but a consequence of more fundamental laws and if you take Statistical Mechanics in college you'll get to re-derive it and see why it works that way. In fact, I'd really recommend taking a Stat Mech class to anyone considering it, it was probably the most interesting class I took in college.

jamesjyu 14y ago

Thanks for sending me down hours of engrossed reading in which I constantly question the nature of my existence.

Devilboy 14y ago

We are Boltzman brains, no?

paol 14y ago
No, I'm a Boltzmann brain. The rest of you are just a figment of my imagination.

Symmetry 14y ago

The idea of Boltzman brains is a good reason to hope that the universe ends with a big crunch.