Entropy, Function and Evolution

My emails to the biosemiotics list.

02.06.2013 17:52

http://www.mdpi.com/1099-4300/12/2/197

Carsten Herrmann-Pillath, Entropy, Function and Evolution: Naturalizing Peircian Semiosis, Entropy 2010, 12(2), 197-242; doi:10.3390/e12020197

I have browsed the paper. As I have expected, the entropy the author talks about has nothing to do with the thermodynamic entropy that has been introduced by Clausius, Kelvin and Gibbs.

p. 204 “Following Gibbs, Jaynes [46] had shown that entropy always refers to a state of ignorance about a physical system.”

The term “the Gibbs/Jaynes version” or “the Gibbs/Jaynes notion” in the paper is completely misleading. Gibbs has nothing to do with Jaynes’ interpretation of the entropy. The entropy considered by Jaynes or in Herrmann-Pillath’s paper has nothing to do with the entropy that we find in Gibbs works.

p. 208 ‘This helps to further clarify the Jaynes statement that entropy is an “anthropomorphic concept.” On first sight, this means that entropy is a notion that is epistemologically objective, because it relates to physical laws, but ontologically subjective, because it relates with particular experimental settings which fix the degrees of freedom of the observed macrostate; the settings themselves reflect mental states of the experimenter.’

This statement shows that apparently the author has not done a lab in experimental thermodynamics and has never used thermodynamics tables to compute equilibrium composition. If you have not done it as well, a good starting point is

JANAF Thermochemical Tables (Joint Army-Naval-Air Force Thermochemical Tables) (ca. 230 Mb)
http://www.nist.gov/data/PDFfiles/jpcrdM9.pdf

where one find a nice introduction.

Let me remind that

(1)  (dS/dT)_p = Cp/T

(2)  (dH/dT)_p = Cp

Provided one assumes that the entropy is an “anthropomorphic concept”, from (1) follows that Cp must be an an “anthropomorphic concept” as well. Thereafter the energy (Eq 2) must also be an “anthropomorphic concept”. There is no difference in this sense between the entropy and the energy.

Finally, provided the author talks about Peircian Semiosis, it would be good to look at Herrmann-Pillath’s paper through Peirce’s pragmatic maxim (Chapter 7 in Cornelis de Waal, Peirce: A Guide for the Perplexed):

Consider what effects, which might conceivably have practical bearing, we conceive the object of our conception to have. Then, our conception of these effects is the whole of our conception of the object.”

One can infer the pragmatic role of the entropy in the JANAF Tables even from the name: Joint Army-Naval-Air Force Thermochemical Tables. To this end, I will also quote from the JANAF Introduction:

Beginning in the mid-1950s, when elements other than the conventional carbon, hydrogen, oxygen, nitrogen, chlorine, and fluorine came into consideration as rocket propellant ingredients, formidable difficulties were encountered in conducting rigorous theoretical performance calculations for these new propellants. The first major problem was the calculational technique. The second was the lack of accurate thermodynamic data.”

By the end of 1959, the calculation technique problem had been substantially resolved by applying the method of minimization of free energy to large, high speed digital computers. At this point the calculations become as accurate as the thermodynamic data upon which they were based. However, serious gaps were present in the available data: For propellant ingredients, only the standard heat of formation is required to conduct a performance calculation. For combustion products, the enthalpy and entropy must be known, as a function of temperature, in addition to the standard heat of formation.“

I am not sure though if Herrmann-Pillath’s paper will survive the application of Peirce’s pragmatic maxim.

02.06.2013 20:30

My comment was about the use of the entropy in the paper and my point was that the entropy in the paper was different from the normal thermodynamic entropy.

As I have just read about Peirce’s pragmatic maxim, I have just tried to use it. This was my first try though to think along such a maxim.


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