From Bob Clark (931214.1700 EST)
With reference to my definition of entropy, Martin Taylor (931208
18:30) notes:
Some textbooks of thermodynamics do define entropy in this form, yes.
And proceeds with reference to Physics Today with an article
elaborating the definition of entropy. Seems like an interesting
paper.
However, my main point was in my next sentence, not included by
Martin:
There is a well known proof that it is intrinsically positive, that
is, it can never decrease in a _closed_ system. A "closed system"
has boundaries which energy cannot pass across.
Could have been stated better. The point is, that entropy applies
_only_ to a system closed to transfer of energy either into or out of
the system. Living systems, at least those of interest, are not
closed in this sense. They ingest and excrete, etc -- take energy in
from their environment and put energy out into their environment.
Therefore, entropy has nothing to do with living systems.
Regards, Bob Clark