T-symmetry 6.2 | Loschmidt’s paradox 4
This drew the objection from Loschmidt that it should not be possible to deduce an irreversible process from time-symmetric dynamics and a time-symmetric formalism: something must be wrong (Loschmidt’s paradox).
The resolution (1895) of this paradox is that the velocities of two particles after a collision are no longer truly uncorrelated. By asserting that it was acceptable to ignore these correlations in the population at times after the initial time, Boltzmann had introduced an element of time asymmetry through the formalism of his calculation.
— Wikipedia on Molecular chaos
If an observer insists to monitor all the microstate information of the observed and the environment, i.e. without leaving any microstate information, that observer would see a time symmetric universe, in the sense that the second law of thermodynamics would not be there anymore.
It would then be meaningless to label any of the two directions of time as “past” or “future”.
— Me@2020-10-12 08:10:27 PM
So in this sense, as long as an observer wants to save some mental power by ignoring some micro-information, the past and future distinction is created, in the sense that there will be the second law of thermodynamics.
— Me@2020-10-12 08:12:25 PM
Time’s arrow is due to approximation. Time’s arrow is due to the coarse-grained description of reality. In other words, you use an inaccurate macroscopic description on an actually microscopic reality.
— Me@2020-10-12 10:41:48 PM
2020.10.13 Tuesday (c) All rights reserved by ACHK