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> Don't put me down. I could have snowed you with differential equations and diagrams instead of what you see everyday. We're being practical and visual rather

> Don't put me down. I could have snowed you with differential equations and diagrams instead of what you see everyday. We're being practical and visual rather than going the math route, essential as that is in chemistry. > The big deal is that all types of energy spread out like the energy in that hot pan does (unless somehow they're hindered from doing so) They don't tend to stay concentrated in a small space. I am trying to loosely connect big ideas here so I might be wrong. If there is fundamental feature of a universal law, then that feature must manifest itself at all scales, as the above statements tries to put forward visually. Maybe this idea of flow spreading out is very general and some kind of summarization of that finer grain flow to coarser flow in the form of Green's theorem or Stoke's Theorem is very general. Kinematic Flow and the Emergence of Time https://arxiv.org/abs/2312.05300 https://arxiv.org/abs/2312.05300

ninetyninenine 2y ago
This is what confuses people. There is this universal law, but you already know about it. It's probability. Increasing Entropy is a result of probability. That's all it is. When you have a bunch of particles and you jostle the particles it is MORE probable for the particles to become spread out then it is to become concentrated in one corner. That probability is what is behind this mysterious force called entropy. Why is it more probable? You just count the amount of possible states. There are MORE possible "spread out" states then there are "concentrated states". In Most systems there are more disorganized states then there are organized states. Think of it in terms of dice. If you roll 10 dice, how likely are you to get some random spread of numbers vs. all the numbers concentrated on 6? Or all numbers concentrated on 1? It's more probable to get a random spread of numbers because there are astronomically more possibilities here. For all numbers concentrated on 1,2,3,4,5, or 6 you only have a total of 6 possible states, all ones, all twos, all threes... all sixes... that's total six states. Random spread occupies 46650 possible states (6^6 - 6). Hence by probability things are more likely to become disordered and spread out simply because there are more possible disordered states. Entropy is a phenomenon of probability. People mistake it for some other fundamental law that mysteriously occurs. No it's not, it makes sense once you understand probability. The real question is, what is probability? Why does it happen to work? Why does probability seem to follow an arrow of time, it doesn't seem symmetrical like the rest of physics.
- lajy 2y ago
  It makes even more sense when you take the law of large numbers into account. The scale we're experiencing most things on is /so/ far removed from the scale on which these probabilities are being expressed. There are more molecules in a cup of water (on the order of 10^24) than there are cups of water in the ocean. If you have a cup of water's worth of matter, you aren't just rolling 10 dice (or even 1000 dice) and looking for mostly 6s. You're rolling a few septillion dice and hoping for a significantly non-normal distribution. It just isn't feasible.
- kgwgk 2y ago
  > Why does probability seem to follow an arrow of time, it doesn't seem symmetrical like the rest of physics. One cannot really oppose probability to "the rest of physics". Probability is not "a part of" physics. Probability is what we use to describe imperfect knowledge of a physical system - and we know more about the past than we do about the future.
  - ninetyninenine 2y ago
    No, probability is a mathematical game with axioms and theorems. Why the rules of this game happens to describe systems where we have imperfect knowledge... nobody knows. Another thing is all of these systems have probability travel in a single direction. Things with high probability are more likely to happen. If time were to go backwards, low probability events will start to spontaneously occur.
    - kgwgk 2y ago
      Ok, so we agree that probability is not a part of physics. I also agree that the question of how to apply probability in physics is interesting. I’m not sure about the “nobody knows” though. I would say that statistical mechanics has been quite successful in “knowing”: https://arxiv.org/pdf/cond-mat/0501322 https://arxiv.org/pdf/cond-mat/0501322
      - ninetyninenine 2y ago

ninetyninenine 2y ago

This is what confuses people. There is this universal law, but you already know about it. It's probability. Increasing Entropy is a result of probability. That's all it is. When you have a bunch of particles and you jostle the particles it is MORE probable for the particles to become spread out then it is to become concentrated in one corner. That probability is what is behind this mysterious force called entropy. Why is it more probable? You just count the amount of possible states. There are MORE possible "spread out" states then there are "concentrated states". In Most systems there are more disorganized states then there are organized states. Think of it in terms of dice. If you roll 10 dice, how likely are you to get some random spread of numbers vs. all the numbers concentrated on 6? Or all numbers concentrated on 1? It's more probable to get a random spread of numbers because there are astronomically more possibilities here. For all numbers concentrated on 1,2,3,4,5, or 6 you only have a total of 6 possible states, all ones, all twos, all threes... all sixes... that's total six states. Random spread occupies 46650 possible states (6^6 - 6). Hence by probability things are more likely to become disordered and spread out simply because there are more possible disordered states. Entropy is a phenomenon of probability. People mistake it for some other fundamental law that mysteriously occurs. No it's not, it makes sense once you understand probability. The real question is, what is probability? Why does it happen to work? Why does probability seem to follow an arrow of time, it doesn't seem symmetrical like the rest of physics.

lajy 2y ago
It makes even more sense when you take the law of large numbers into account. The scale we're experiencing most things on is /so/ far removed from the scale on which these probabilities are being expressed. There are more molecules in a cup of water (on the order of 10^24) than there are cups of water in the ocean. If you have a cup of water's worth of matter, you aren't just rolling 10 dice (or even 1000 dice) and looking for mostly 6s. You're rolling a few septillion dice and hoping for a significantly non-normal distribution. It just isn't feasible.
kgwgk 2y ago
> Why does probability seem to follow an arrow of time, it doesn't seem symmetrical like the rest of physics. One cannot really oppose probability to "the rest of physics". Probability is not "a part of" physics. Probability is what we use to describe imperfect knowledge of a physical system - and we know more about the past than we do about the future.
- ninetyninenine 2y ago
  No, probability is a mathematical game with axioms and theorems. Why the rules of this game happens to describe systems where we have imperfect knowledge... nobody knows. Another thing is all of these systems have probability travel in a single direction. Things with high probability are more likely to happen. If time were to go backwards, low probability events will start to spontaneously occur.
  - kgwgk 2y ago
    Ok, so we agree that probability is not a part of physics. I also agree that the question of how to apply probability in physics is interesting. I’m not sure about the “nobody knows” though. I would say that statistical mechanics has been quite successful in “knowing”: https://arxiv.org/pdf/cond-mat/0501322 https://arxiv.org/pdf/cond-mat/0501322
    - ninetyninenine 2y ago