# Re: comp and Maxwell demon

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On 16 Jan 2011, at 22:27, Evgenii Rudnyi wrote:```
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Thanks for the answer. My question was due to the fact that comp presumably can simulate more than we observe. Let me check if I have understood your answer correctly. I will cite a paragraph from my text
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http://blog.rudnyi.ru/2010/12/entropy-and-artificial-life.html

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We bring a glass of hot water in the room and leave it there. Eventually the temperature of the water will be equal to the ambient temperature. In classical thermodynamics, this process is considered as irreversible, that is, the Second Law forbids that the temperature in the glass will be hot again spontaneously. It is in complete agreement with our experience, so one would expect the same from statistical mechanics. However there the entropy has some statistical meaning and there is a nonzero chance that the water will be hot again. Moreover, there is a theorem (PoincarĂ© recurrence) that states that if we wait long enough then the temperature of the glass must be hot again. No doubt, the chances are very small and time to wait is very long, in a way this is negligible. Some people are happy with such statistical explanation, some not.
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Have you meant that the Universal Dovetailer will act for such a situation according to PoincarĂ© recurrence?
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The UD will do that an infinity of times, given that the PoincarĂ© recurrence is a computable process. But the physical laws are sum on first person views, based on a continuum of histories, so to relate thermodynamic to the UD is certainly not obvious at all. The UD is just a way to provide the minimal third person ontology (the 'everything') needed when we assume mechanism, and its role is to build a mathematical formulation of the mind-body problem (if only to illustrate that science has not yet choose between Plato and Aristotle).
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Bruno

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on 16.01.2011 17:50 Bruno Marchal said the following:
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```You can simulate it. But you cannot program it. It uses a huge amount
of information that it is hard to extract from the environment. I
would say. In a larger sense, in which we are ourself Maxwell demon,
you can filter it from long computation. They will transform
selective information into energy. they will economize. The Universal
Dovetailer does generate all possible Maxwell daemons, but I guess
they are typically distributed sparsely in the set of all
computations. Quantum Maxwell demon? That might explains the origin
of life, but that might be a too cheap explanation. I should revised
quantum information theory, but I have already hardly the time to do
the real thing, which is to extract the quantum information from
classical information + self-duplication and other self-perturbation
(or to convince others to do the work, or that such a work has to be
done to get both the qualia and the quanta). Interesting but hard
question.

Bruno

On 15 Jan 2011, at 18:22, Evgenii Rudnyi wrote:

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```I am trying to understand what the hypothesis comp is about. It
would be interesting to understand whether the Maxwell demon could
be simulated or not. Any idea?

Evgenii

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