From: jlg@cochiti.lanl.gov (Jim Giles)
Subject: Re: sci.skeptic FAQ version 0.2.
Organization: Los Alamos National Laboratory
Distribution: na
Date: Tue, 1 Sep 1992 23:19:03 GMT

In article <25915@dog.ee.lbl.gov>, sichase@csa1.lbl.gov (SCOTT I CHASE) writes:
|> [...]
|> You *really* need to study some physics.  All the microstates available
|> to the particles in the box have exactly the same energy.  I have no 
|> idea what "conservation law" you are refering to here.

You *really* need to read a person's article in its entirety before making
ad-hominem remarks.  You claimed that the entropy was changed because the 
particles in the box happened to cluster in the corner.  Entropy, like
internal energy, is a state variable and is *constant* if the system 
is in equilibrium - no matter which corner the particles cluster in,
or fail to cluster in.  In short, you were wrong.  Yet, I did not imply
that *your* knowledge of physics was negligible - even if your memory
of this particular point was faulty.

Further, *you're* the one telling *me* that a state variable of a 
thermodynamic system is *not* conserved in a closed system -  and you 
claim that *I* don't know anything about physics!

|> [...]
|> You don't understand what "equilibrium" means in statistical physics.
|> Imagine putting your box in contact with the traditional heat bath.
|> "Equilibrium" refers to the partition of energy between your system
|> and the heat bath - not to any particular microstate of the box at the
|> equilibrium energy (or temperature).   There is no single "equilibrium"
|> configuration in the sense you are trying to use it.  

In statistical mechanics, the term equilibrium refers to the entire
set of available micro-states and their relative probabilities.  If
that is fixed, then you are in equilibrium.  Period.   The *specific* 
one of those states that a system occupies at any given time is irrelevant.  
That's why it's irrelevant whether all the particles gather to the corner 
or not.  Which is what *you* claimed *DOES* matter.

You're also the one who claimed that entropy was only relevant to
static equilibrium - when, in fact, it's *defined* in terms of
differential quantities.  In short, you were wrong.  Yet, you 
consistently state that *I* don't know any physics.  Well, maybe 
so, maybe not.  But if I *don't* understand physics, I know someone 
who shares that distinction with me - and I'm responding to him right 
now.  Now, can we cut the one-upsmanship and discuss this reasonably?

|> [...]
|> >The term `order' is not part of the *thermodynamic* definition of
|> >the second law nor of entropy.  In statistical mechanics (a related
|> >but different field), the *definition* of entropy is in terms of the
|> 
|> Statistical mechanics is the entire modern basis of classical thermodynamics.
|> I'm not sure how different that makes it.  But let's not pick nits.

But, I'm demanding to pick a particular nit - namely the use of 
the inappropriate term `order' in discussions of the second law 
of thermodynamics.  Please find *any* reference that uses the term 
`order' in a technical way or admit that your use was in error.

|> [...]
|> You don't need to coin new lingo to explain the physics.  Order is most
|> definitely an appropriate concept when dealing with entropy.  The statement
|> "closed systems tend to a more disordered state" can be made precise with the
|> language of stat mech, creationist misuse of the phrase notwithstanding.

"You say your office is messy - or *disordered*?  Let me turn on the
air conditioner and cool it down.  The decrease in entropy will
increase the *order* in your office."  Hmm. the word `disorder' 
doesn't seem to correspond to the concept you're trying to convey.

Yes, you can make the statement "closed systems tend to a more 
disordered state" be a quite precise one.  But only by redefining 
`disorder' to have a meaning which is *completely* different from 
its meaning in normal discourse.  How is using a term in such
a completely unfamiliar way *appropriate*?  You don't need to coin 
new lingo to explain the physics.  So don't.  Meanwhile, the phrase 
"closed systems tend toward the maximum diversity of energy states"
captures the concept in statistical mechanics quite precisely.

In the meantime, why are you so intent on defending the use of this
term in this way?   I've got six undergraduate thermodynamics texts
and only *one* of them uses the word at all (and then, only *once*
in an informal discussion).  It's not like the word was engrained
in this new meaning without hope of extracting it.  I've not seen
the term in texts *above* the undergaduate level at all.

-- 
J. Giles