[Fis] Fwd: Entropy, the Second Law, and Life

Mon Jan 18 12:32:37 CET 2021

Dear Pedro,
Sorry  for the long delay in my answer.
I will answer briefly since a long answer would take too much time and
space.
1. I fully agree that entropy and SMI should be given different names. The
fact that Shannon called his measure ( the SMI ) entropy, was a grave
mistake.
This has caused great confusion in both thermodynamics and information
theory. ( confusing entropy with SMI and SMI with “information” is very
common)
2. I agree that in some specific processes the entropy change may be
associated with increase in “freedom” or with “spreading.”
This is also true for “disorder” however, none of these interpretations can
be derived from the definition of entropy. So, in general, they are not
correct interpretation of entropy.
3.  Of course the Gibbs energy is the quantity which is more fundamental in
a system at constant T and P. The formulation of the second law in terms of
entropy is valid only for isolated systems.
Best wishes
Arieh

On Wednesday, January 13, 2021, Pedro C. Marijuan <pcmarijuan.iacs at aragon.es>
wrote:

> Dear Arieh and FIS Colleagues,
>
> Again, regarding the interpretation of entropy as information or
> uncertainty (respect locations & momenta), my suggestion is that we should
> call "something else" to the extensive magnitude we are measuring.
> Otherwise, we easily give room to all those pseudo-interpretations you
> wonderfully describe and the general confusion with information. When I was
> teaching a bio-discipline for engineer students, I was using the term
> "freedom". You are measuring the degrees of freedom of the system, I was
> telling, how much they have changed either increasing or decreasing along
> the process. And that quantity of degrees of freedom when multiplied by the
> temperature gives the energy gained or lost via entropy change. So, the
> application of SMI to the system what tells us is about the degrees of
> freedom statistical measurement. In short: the new freedom status of the
> system. It may not be a terrific theoretical interpretation, but my
> students loved it (I confess that previously I was using Lambert's
> "dispersal", until I saw your criticisms in the web).
>
> All of this is well depicted in Gibbs' formula for the free energy of
> chemical reactions, with the part due to ENTHALPY change (basically
> internal energy), and the part due to ENTROPY change x Temp. Given than
> most biological --all!-- occur to room temperature (or far lower), the
> resulting contribution of entropy is pretty moderate. Actually I was
> checking chemical tables of many biological reactions, and the contribution
> of entropy was generally an order of magnitude lower than enthalpy--around
> 10% or less. I wonder --following Howard's comment days ago-- all the
> obsession with entropy and the universal neglect of enthalpy. It is
> enthalpy (or internal energy, or free energy) the big concern of all
> biological systems, "the food of today", rather than the negentropy or low
> entropy you graciously comment.
>
> I had also a comment regarding Joseph's and Jerry's on Pauli Exclusion
> Principle, but better for another day.
>
> Best wishes to all--Pedro
>
> El 08/01/2021 a las 19:22, Arieh Ben-Naim escribió:
>
> Dear Pedro and everyone else interested.
>
> I will briefly answer your questions, as I have discussed these in more
> details in my previews publications.
> Regarding the interpretation of entropy as a measure of information and as
> uncertainty.
> In my view these are the only valid interpretations of entropy, provided
> that one specifies information about what, and uncertainty with respect to
> what. Both of these are discussed in my book on “Information Theory” and in
> “Entropy: the Greatest Blunder in the History of Science.”
>
> Regarding the question of dimensions for entropy, I have also discussed
> that in my book on “Farewell to Entropy.”
> In my view this is a result of historical “accident” that temperature was
> given a special dimensions that were not used before in physics:”degrees”
> If temperature was given the dimensions of energy, then entropy would
> become dimensionless. This would ease the acceptance of the only correct
> interpretation of entropy either as a measure of information or a measure
> of uncertainty (in both cases the information and uncertainty with respect
> to the distribution of locations and momenta of all particles of the system
> at equilibrium)
>
> In my recent book I have criticized both Shermer’s and Pinker’s misuses of
> the concept of entropy in their books.
>
> I hope I have answered your questions, though very briefly.
> Best regards
> Arieh
>
> On Fri, Jan 8, 2021 at 15:40 Pedro C. Marijuan <pcmarijuan.iacs at aragon.es>
> wrote:
>
>> Dear Arieh & FISers,
>>
>> My appreciation for your elegant and lively contribution. Reading about
>> labeling the food on their "negentropy content"  or advising on low
>> entropy food (icy water!) was a most humorous way to criticize all the
>> nonsense and "mystical mystery tours" around entropy. Particularly,
>> Atkins (& Dawkins) quasi-religious views have always been unswallowable
>> for me. Anyhow, two further aspects I would like to hear from you.
>>
>> First, to put it most briefly, what basic, visual image would you convey
>> for an intuitive understanding of entropy beyond the technicality of
>> SMI? Uncertainty, chaos, disorder, diffusion, dispersal... some many
>> terms around!  I could see years ago some heated exchanges you had with
>> Frank Lambert, the champion of entropy as energy dispersal. There is
>> also a longish comment on how Steven Pinker approaches
>> entropy-information-evolution-cognition as the four fundamental concepts
>> in our scientific understanding of the world. He is wrong (IMO) in all
>> of them! Although it he is an extraordinary social psychologist the
>> basic sci. background he proposes is tainted. If we could give a more
>> sound "tetrad" even with those same concepts, it would be a great
>> outcome. Clarifying entropy in all aspects we could advance would a
>> terrific step.
>>
>> And second (maybe to be discussed later on) do you accept "dimensions"
>> for entropy? The units of jules/degreeK aren't they derived from having
>> entered the Boltzmann's constant? Why do we need at all separate units
>> for temperature and energy?
>>
>> Thanks for all the exchanges so far!
>>
>> Best--Pedro
>>
>> --
>> -------------------------------------------------
>> Pedro C. Marijuán
>> Grupo de Bioinformación / Bioinformation Group
>>
>> pcmarijuan.iacs at aragon.es
>> http://sites.google.com/site/pedrocmarijuan/
>> -------------------------------------------------
>>
>>
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> --
> Prof. Arieh Ben-Naim
> Department of Physical Chemistry
> The Hebrew University of Jerusalem
> Jerusalem, 91904
> Israel
>
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> --
> -------------------------------------------------
> Pedro C. Marijuán
> Grupo de Bioinformación / Bioinformation Group
> pcmarijuan.iacs at aragon.eshttp://sites.google.com/site/pedrocmarijuan/
> -------------------------------------------------
>
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-- 
Prof. Arieh Ben-Naim
Department of Physical Chemistry
The Hebrew University of Jerusalem
Jerusalem, 91904
Israel
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