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Re: Order being born from disorder?



David contributes:

Warning! Excessively long post to follow!

ending with

[my tag line]
On rereading this I'm not sure I've done anyone a service, but I expect
that I'll attract some potshots, and that should focus discussion on
something interesting.

I hope you (Leigh) don't consider this post as anything more than a few
potshots. Unfortunately, (as is the usual case with my posts) it is too
long and its length may make it seem more like a machine gun burst (which
it is not meant to be).

You clarified a few things quite nicely, David, and I don't feel at all
perforated. We could write a textbook a la Galileo's "Two New Sciences".
Of course we'd need a third collaborator...

I learned from your note that von Neumann is responsible for the confusion
generated by the usurpation of the term "entropy". *He* didn't understand
it, something I can relate to in a mathematician. Entropy is a physical
idea. Boltzmann et al. gave it a microscopic mathematical interpretation
and subsequently many took that to be the fundamental meaning. Do not
forget that the macroscopic and microscopic definitions are of *exactly*
the same quantity, and the empirical basis for the validity of classical
thermodynamic predictions in which entropy plays a part are based mainly
on the classical, not the statistical, definition of the concept. For
example, your comment about photons accompanying the performance of
reversible exchange in the positions of cores is gratuitous. When we
speak of such processes we speak in ideal terms; it is in principle, but
not in practice, possible to exchange cores reversibly. The ideal is
approached as the rapidity with which the exchange is made diminishes.
There are a couple of other nits I might pick, but like your first post,
this is on the whole a very nice contribution. I'm glad I stuck my neck
out if it inspired you to write it.

Leigh