nshepperd comments on Entropy and Temperature - Less Wrong

26 Post author: spxtr 17 December 2014 08:04AM

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Comment author: Lumifer 17 December 2014 07:21:12PM 2 points [-]

so temperature is in the mind

I am not quite sure in which way this statement is useful.

"..and for an encore goes on to prove that black is white and gets himself killed on the next zebra crossing." -- Douglas Adams

Comment author: nshepperd 18 December 2014 06:23:09AM 1 point [-]

I am not quite sure in which way this statement is useful.

Is that because you didn't read the rest of the post?

"Temperature is in the mind" doesn't mean that you can make a cup of water boil just by wishing hard enough. It means that whether or not you should expect a cup of water to boil depends on what you know about it.

(It also doesn't mean that whether an ice cube melts depends on whether anyone's watching. The ice cube does whatever the ice cube does in accordance with its initial conditions and the laws of mechanics.)

Comment author: Lumifer 18 December 2014 04:56:13PM *  0 points [-]

So now that you've told me what it does NOT mean, perhaps you can clarify what it DOES mean? I still don't understand.

In particular, the phrase "in the mind" implies that temperature requires a mind and would not exist if there were no minds around. Given that we are talking about classical systems, this seems an unusual position to take.

Another implication of "in the mind" is that different minds would see temperature differently. In fact, if you look into the original EY post, it explicitly says

Is the water colder, because we know more about it? Ignoring quantumness for the moment, the answer is: Yes! Yes it is!

And that makes me curious about phase changes. Can I freeze water into ice by knowing more about it? Note: not by doing things like separating molecules by energy and ending up with ice and electricity, but purely by knowing?