Oscar_Cunningham comments on The Second Law of Thermodynamics, and Engines of Cognition - Less Wrong

58 Post author: Eliezer_Yudkowsky 27 February 2008 12:48AM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (65)

Sort By: Old

You are viewing a single comment's thread. Show more comments above.

Comment author: Oscar_Cunningham 18 December 2013 09:27:21PM *  0 points [-]

Why doesn't observed entropy decrease as well, since phase space is preserved with the following?

X2Y1 -> X1Y1
X4Y1 -> X1Y2
X6Y1 -> X1Y3
X8Y1 -> X1Y4

(I guess DaveInNYC won't read this but I guess someone else might.)

If you lump together X's starting state into X2-X8 then you can't be sure that it isn't actually X3, X5 or X7. So you have to look at where those possibilities go as well. Then the entropy can't go down (since by Liouville's Theorem they have to go somewhere different from X2, X4, X6 and X8).