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From: gjphw@iham1.UUCP
Newsgroups: net.origins
Subject: Re: Thermodynamics
Message-ID: <214@iham1.UUCP>
Date: Tue, 18-Sep-84 14:30:39 EDT
Article-I.D.: iham1.214
Posted: Tue Sep 18 14:30:39 1984
Date-Received: Tue, 25-Sep-84 03:23:13 EDT
References: <282@uwmacc.UUCP>
Organization: AT&T Bell Labs, Naperville, IL
Lines: 135



   In a recent submission, N. Sharp posted a comment concerning an  application
 of  nonequilibrium  thermodynamics.   In reply, P. DuBois provided a quotation
 from a two part article that appeared in *Physics Today*  (vol  25,  Nov.  and
 Dec.  1972)  entitled  *Thermodynamics  of  evolution*  which  was  written by
 I. Prigogine et al.  Also included was a second  quotation  (from  *Impact  of
 Science on Society*) that I have not checked.

      > ..."The point is that in a non-isolated system there exists a
      > possibility for formation of ordered, low-entropy structures
      > at sufficiently low temperatures.  This ordering principle is
      > responsible for the appearance of ordered structures such as
      > crystals as well as for the phenomena of phase transitions.
      >
      > Unfortunately this principle cannot explain the formation of
      > biological structures.  The probability that at ordinary
      > temperatures a macroscopic number of molecules is assembled
      > to give rise to the highly-ordered structures and to the
      > coordinated functions characterizing living organisms is
      > vanishingly small.  The idea of spontaneous genesis of life
      > in its present form is therefore highly improbable, even on
      > the scale of the billions of years during which prebiotic
      > evolution occurred."
      >
      > Prigogine, Nicolis and Babloyantz, "Thermodynamics of Evolution."
      > Physics Today, 1972, v. 25.
      >
      > Speaking of dissipative structures and order through fluctuations,
      > Prigogine writes,
      >
      > "...let us have no illusions - our research would still leave us
      > quite unable to grasp the extreme complexity of the simplest
      > of organisms."
      >
      > Prigogine, "Can Thermodynamics Explain Biological Order?"  Impact
      > of Science on Society, 1973, v. 23(3).
      >
      > (i) WRT the second quote: this is not to say that no progress
      > can be made in the direction of understanding such complexity.
      > I say this explicitly in the attempt to ward off the spate of
      > non-arguments such as were seen in the variable 'c' affair, in
      > which I was alleged to be arguing for a variable value of 'c'.
      > I didn't say 'c' varies there, and I don't say here that thermo
      > will never explain or describe biological complexity.
      > But perhaps one might reasonably express skepticism about the
      > place of evolution in producing that complexity?
      >
      > (ii) creationists are said to be "notorious" for quoting out
      > of context.  If you think I'm doing so here, explain why,
      > please.

   With respect to the first of Mr. DuBois' comments (i), the recognition  that
 the  second quotation of Prigogine makes a cautionary statement concerning his
 research is indeed important.  However, with respect to the first, and  longer
 quotation,  of  Prigogine (ii), I intend to show that it has been taken out of
 context.

   Allow me to continue the text from the  *Physics  Today*  article  with  the
 paragraph  that  follows  the  above quotation and which is used to finish the
 section dealing with equilibrium thermodynamics:


        The conclusion to be drawn from this analysis is that the apparent
     contradiction between biological order and the laws of physics - in
     particular the second law of thermodynamics - cannot be resolved as
     long as we try to understand living systems by the methods of the
     familiar equilibrium statistical mechanics and equally familiar
     thermodynamics.


   There is no dispute that the empirically discovered and idealized rules  for
 equilibrium  systems  (i.e.,  the  four  laws of thermodynamics) are unable to
 explain any increase in order.  Indeed, equilibrium thermodynamics  (classical
 thermodynamics) does not permit any increase in order, or even the maintenance
 of locally ordered systems.  What does cause a furor is the inappropriate  and
 naive  application of equilibrium thermodynamics (typified by uniform tempera-
 ture, pressure, mole fractions) to  nonequilibrium  conditions  (systems  with
 gradients  or spatial and time variations in temperature, pressure, and chemi-
 cal concentrations).

   The out-of-context charge arises because we are led to believe from the ori-
 ginal quotation that Prigogine was referring to nonequilibrium thermodynamics.
 In fact, the quotation comes from the leading section of the  article  showing
 that  while  equilibrium thermodynamics does allow ordered systems at very low
 temperatures (interesting to me, though reasonable), it does not  support  the
 spontaneous formation of order at ordinary (e.g., room) temperatures.

   Systems are given one of three classifications in thermodynamics.  The first
 is  called  isolated  where no energy or matter can be exchanged.  A second is
 called closed because while energy can be exchanged between the system and the
 outside environment, matter cannot be exchanged.  The third category is called
 open, with both matter and energy being exchanged.  Prigogine's  reference  to
 *nonisolated*  was  with  respect to the closed system that he used to control
 the equilibrium temperature of the example system under discussion.  It is due
 to  the  incorrect impression that the section quoted from the *Physics Today*
 article was in reference to nonequilibrium thermodynamics, rather than  merely
 a  closed  system at equilibrium, that merits the out-of-context label.  (Note
 also that the designation of the whole universe as closed is not the  same  as
 classifying a thermodynamic system as closed.)

   Allow me to continue on my soapbox.  The studies of thermodynamics and  sta-
 tistical  mechanics  cover  three distinct regimes.  The first is the familiar
 equilibrium thermodynamics, with its four laws (numbered 0 - 3).  This  occurs
 for  systems  having  uniform temperatures, pressures, and chemical concentra-
 tions.  The second is thermodynamics in the linear regime, also known  as  the
 thermodynamics  of  irreversible processes.  Applied a posteriori, this occurs
 in systems of shallow or weak gradients.  These gradients can only be  linear,
 and  spontaneous increases in order are not possible.  (It was for his work on
 the thermodynamics of irreversible processes that Prigogine received his Nobel
 prize in physics.)

   A third regime is called nonequilibrium thermodynamics.   Systems  to  which
 this  applies,  again a posteriori, have strong gradients which are not neces-
 sarily linear.  Prigogine has already shown that in certain chemical  systems,
 spontaneous  increases  in local order are possible in strongly nonequilibrium
 conditions (open systems).  It is these nonequilibrium conditions  which  seem
 to  apply  to  virtually all observed situations on Earth (at least within the
 biosphere) and appear to be most promising for further work.  Prigogine et  al
 are  busily  trying  to  discover  the mathematical formulations that describe
 these systems that are far from equilibrium.

   Even in his technical writings and monographs,  Prigogine  has  been  making
 claims  that  his work in nonequilibrium thermodynamics can be used to explain
 all kinds of phenomena, especially living systems.  These claims have all  too
 often been difficult to substantiate or understand at this time.  The *Physics
 Today* quotation struck me as out of character for Prigogine,  so  I  explored
 it further.  The *Impact* quotation is refreshingly cautious.

-- 

                                    Patrick Wyant
                                    AT&T Bell Laboratories (Naperville, IL)
                                    *!iham1!gjphw