“I am not for or against Goethe. A great writer, he used a theory of chemical combination (elective affinities) that was already outmoded by his time, to write a great novel of human relationships using that theory as a metaphor. None has done that since.
Quantum mechanics has in it the key to chemical bonding. I use it, in approximate ways. Affinities – opposites attracting each other, electrostatically, emerge. But also like atoms forming strong, covalent bonds. One can put the results in the language of affinities to describe approximately what happens, and we often do that to beginning students. Also chemists often use anthropomorphic language, and it’s just fine.”
|Hoffmann's 2012 take on Goethe's Elective Affinities, incorrectly describing it as using "outdated theory", which is hardly the case: chemical bonding theory was not upgraded until Edward Franklin and his 1852 "combining power" valency theory (see: history of chemical bonding theory); he compares Goethe to Primo Levi (a very primitive resemblance); and seems to be unaware of Tom Stoppard's Elective Affinities remake, the 1998 Arcadia, where to Stoppard's credit he does incorporate some modern upgrade theory, such as the second law, sexual heat, steam engine theory, chaos theory, among others.|
(a) Goethe did not consider his human affinities theory to be metaphor, as evidenced by his March 23, 1810 advertisement (Morning Paper for the Educated) wherein he summarized or rather defended his position that “there is after all only one nature”, meaning that he considered the view presented therein to be reality;
(b) that at as Helmholtz proved in 1882, the measure of affinity in human reaction conditions (freely-going, isothermal, isobaric, surface-attached, coupled, cyclical, heat-driven chemical reactions) is Gibbs free energy changes, meaning that the modern physical scientist is faced with the oblique task of having to redefine human existence in the language of pure and applied chemical thermodynamics (human chemical thermodynamics), which is a daunting yet wondrous and elusive task, to say the least (meaning in detail that one has to master the 1,158 Gibbs-Clausius equations);
(c) as science historian Henry Leicester has summarized, in his Historical Background of Chemistry (1956), Gilbert Lewis and Merle Randall's influential 1923 textbook Thermodynamics and the Free Energy of Chemical Substances "led to the replacement of the term 'affinity' by the term 'free energy' in much of the English-speaking world", meaning that for chemists educated in the 1930s or later there existed a great unwritten divide or rather disjunct in knowledge between the quest to measure chemical affinity (1718-1923) and the years of modern chemical thermodynamics (1923-present) both of which are tied up in the following equation: