Re: Entropy, Objectivity, and Timescales

[jmclean@chem.ucsd.edu (James Mclean)]

David Bowman says:
> However, Leigh quotes Dan and then comments:
> > ...
> > > Look, I don't want to argue quantum mechanics here.  But I've never
> > > before heard anyone claim that you need to understand quantum
> > > indeterminacy to understand entropy.
> >
> > You don't have to know anything about quantum mechanics to understand
> > entropy. It can be understood entirely as a macroscopic classical
> > phenomenon.
>
> I'm glad to see that both Dan and Leigh (and me) can now agree on (at
> least) this.

I'm not sure about the nature of this agreement, because of uncertainty
about the word "understand".

Certainly entropy can be understood at the level of thermodynamics without
resorting to QM.  That's the level of understanding reached before the turn
of the century.  And it is the level of understanding to which I thought
Leigh was refering in the above quote.

But this discussion has been about a 'deeper' understanding*, at the level
of statistical mechanics.  One in which microstates become a topic for
discussion, and the entropy is descibed in terms of numbers of accessible
microstates.

Is it true that all agree that QM is unneccessary to understand entropy at
this *statistical mechanics* level?

-- 
--James McLean
jmclean@chem.ucsd.edu
post doc
UC San Diego, Chemistry

* I put deeper in quotes because I don't mean to claim that it is 'better'
in any particular way.