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What Is Entropy?

(jasonfantl.com)
287 points jfantl | 1 comments | 14 Apr 25 18:32 UTC | HN request time: 0s | source
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karpathy ◴[14 Apr 25 21:43 UTC] No.43686645[source]▶
What I never fully understood is that there is some implicit assumption about the dynamics of the system. So what that there are more microstates of some macrostate as far as counting is concerned? We also have to make assumptions about the dynamics, and in particular about some property that encourages mixing.
replies(3): >>43686753 #>>43686847 #>>43687472 #
1. oh_my_goodness ◴[14 Apr 25 23:40 UTC] No.43687472[source]▶
In equilibrium we don't have to make an assumption about the dynamics or the mixing. We just expect to see the most probable state when we measure.

It's interesting to try to show that the time average equals the ensemble average. It's very cool to think about the dynamics. That stuff must be happening. But those extra ideas aren't necessary for applying the equilibrium theory.