Brian Keating's Lurid Pink Podcast - Did Stephen Wolfram Finally Prove the Second Law of Thermodynamics?

Well I don't know, because I haven't read his book, but see The Second Law: Resolving the Mystery of the Second Law of Thermodynamics by Stephen Wolfram. 

At 24:43 I always get lost at this point in the description of physical entropy. "Entropy is: You know a certain number of things about a system, a certain amount about a system, and you say 'there are gas molecules and they're all in this box, and there are a billion of them' and that's all you know. Then the question is 'well, how many possible configurations of the system could there be that are consistent with those constraints that they have?' ... as Boltzmann originally said, it's sort of quantized, and that the gas molecules are just in some grid of possible positions, and you say 'how many possible positions are they in?' and entropy is just the exponent, of how many possible configurations there are." My problem is that all you know is how many molecules are in that box, but what is it you need to know about what particular configuration they are in within the box? surely it's some macroscopic measurement of the whole contents of the box, but one which somehow doesn't require your knowing more than the total NUMBER of particles? That's usually temperature, isn't it? Or mean free path or average speed or something like that. And that is something more than just the number of particles in the box. To know that you have to make a measurement and affect the particles in some way, by sticking the bulb of a thermometer into some part of the box or something. Logically, this is more than just knowing how many particles are in there: it's knowing something about the fact that they are separate entities in different places (parts of the grid) so that is an assumption you are implicitly making "these molecules are all separate distinguishable things" and then how does any sort of counting of configurations tell you anything about what is really going in there? You assume, for example, that they are separate indistinguishable things, all identical, apart from their positions and velocities, or apart from what 'ensemble' of positions and velocities they have or something, but then on what basis are you counting the number of possible internal states of the system? Is it the same state when all the particles are in one box (3,1,5) as when they are in box (3,5,1) of an n by n by n cube? Presumably not. But why not? Because you put your thermometer in box (3,5,1) and they aren't there? This is how Ilya Prigogine explained it in terms of correlations between the particles (which Wolfram calls 'encryption' of the past states in the present state). Prigogine explained it by saying that the evolution of the system is irreversible because at the moment you get the information about the present state of the box the system is thermodynamically open and you cannot affect any reversal of the evolution of the system without opening it in this way. Prigogine was talking about microscopic correlations, not macroscopic statistical correlations however. It seems to me that Wolfram is gung-ho about reducing the phenomena to atoms and molecules, and then he posits "irreducible computation" to explain the things he can't explain otherwise. But that is not how science is supposed to work is it? We don't prove scientific statements, we test them, and then we produce theories which further test those assumptions, so when you 'prove' the second law of thermodynamics, assuming the atomic nature of the particles you are not really doing physics. But it's over thirty years since I read Prigogine and Stengers' book "Order out of Chaos" so maybe I am misrepresenting them. It's a great book though. See Order Out of Chaos: Man's New Dialogue With Nature By Ilya Prigogine and Isabelle Stengers.

I have only listenend to this up to 40:56. Maybe later, ...

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I really enjoyed this talk from last August, but I didn't post it on my blog because the poor woman is a Chemical Engineer and, ... well. 

Katie Robertson - A history of thermodynamics in 15 minutes (from 'The demons of thermodynamics)

See the full talk here: The demons of thermodynamics.

See this paper from 200/2001: The Origins of Time-Asymmetry in Thermodynamics: The Minus First Law by Harvey R. Brown and Jos Uffink which you can read right now, if you want to!

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