Re: Lizard engines and rat engines


"Tim Tyler" <tim@xxxxxxxxxxx> wrote in message news:db2792$2a5b$1@xxxxxxxxxxxxxxxxxxxxxx
> There is another candidate law, along the lines of saying that if
> there are several ways of doing things, thermodynamics often seems
> to favour the one that dissipates the most entropy. It is kind-
> of like the thermodynamic opposite of the principle of least action.
>
> As I've described it, that "law" is in desperate need of cleaning
> up and making presentable. However, that task looks like a
> challenging one to me - and I'm not sure something neat, clean
> and law-like will emerge from the idea at the end of the day.

Well put. I can agree with this.

> There are some more candidate laws on the horizon, though their
> outlines are perhaps less distinct.
>
> Assuming for the moment, that we wind up with two more "laws" -
> roughly along those lines. Should they be "marketed" as laws
> four and five?

We already have two more "laws" that are fairly fundamental.
Onsager's reciprocity relationship and Prigogine's law of
minimum entropy production. Both apply to the "linear" regime
close to equilibrium. Neither has been marketed as a fourth
law of thermodynamics. But their logical status is similar
to that of the second law. They can be derived using statistical
arguments from more fundamental laws of physics. Onsager's
reciprocity law, for example, is a consequence of the time-reversal
invariance of fundamental physics and the principle of detailed
balance.

Coming up with new "laws" that apply to situations far from
equilibrium - especially if they are supposed to apply to ALL
situations far from equilibrium - strikes me as very difficult.
Perhaps we can at least come up with a better characterization
of some special far-from-equilibrium situations - phase transitions,
say, or dynamic steady states.


.

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