
A 2002 "human chemistry" interpretation of Goethe's theory of elective affinities. [2]

In science, Goethe's human chemistry, or Goethe's "human chemical theory", refers to the version of human chemistry conceived by German polymath Johann Goethe, from 1796 to 1832, the time of his end, called by him "elective affinities", as largely presented as a set of coded "principles", as he stated, in his 1809 physical chemistry based novella Elective Affinities.

Overview
Goethe viewed people as "metamorphosized", a term he adopted from Ovid, types of human chemical species that react with each other in relationships, both intimate, social, and political, are no different than chemical species and that just as the relationships of chemical species are predetermined by the laws of affinity (the precursors to the laws of quantum valency and chemical thermodynamics) as detailed on affinity tables, then so to are the relationship lives of people. [1]

This theory, the notes of which he destroyed, was published in cryptic form in the 1809 novella Elective Affinities. This was written when Goethe was sixty-one and he considered it his greatest work. Although each chapter in the novella depicts a basic human chemical reaction described in story form, in the famous "chapter four" is the characters intermingle the chemical theory with human existence to a brilliant effect.

Categorization
In categorization terms, Goethe's human chemistry, might be well compared to Empedocles human chemistry (450BC), whom Goethe cites, Schopenhauer’s human chemistry (1818), who was Goethe's student, Carey’s human chemistry (1858), Huxley’s human chemistry (1871), Adams’ human chemistry (1885), Drier’s human chemistry (1910), Fairburn’s human chemistry (1914), Thims’ human chemistry (1995), Tarnopolsky’s human chemistry (2009) (see: HC pioneers).


Étienne Geoffroy's 1718 affinity table.

Étienne Geoffroy's 1718 affinity table.

Laws of affinity
In the history of chemistry, there are at least a dozen or more laws of affinity, depending on which chemist is sourced. One of the first, was Plato's c. 390 BC affinity law that "like tends towards like". Over the years, these affinity laws became more elaborate and complex as new chemical discoveries occurred.

The seed for the theoretical structure of Goethe's novella was Geoffroy's first law of affinity as stated in 1718 by French physician and chemist Étienne Geoffroy, that "whenever two substances are united that have a disposition to combine and a third is added that has a greater affinity with one of them, these two will unite, and drive out the other." To expound on this law, using data from the 1718 edition of Newton's Opticks (query 31), Geoffroy made a sixteen-column, eight-row, affinity table containing twenty-four reacting species, showing specifically what affinity reactions would occur between various combinations of reactants.

At the head of each column is a header species with which all species below can combine or have a rapport with. The latter are so placed such that any higher species replaces all others lower in the column from their compounds with that at the head of the table. In other words, the species at the head of the table can potentially react with any species below it. All the species below the header species are ranked by chemical affinity preferences relative to the top species, with a higher rank corresponding to a higher affinity tendency. The species at the bottom of each column, for instance, have the least amount of affinity for the header species. If the bottom species is in a weakly bonded relationship with the header species, any species above it can potentially displace it from its attached partner.

Goethe, in turn, viewed Geoffroy’s affinity table as though it were filled with different chemically reactive people with varying amounts of bonding affinity for one another. Each header species, for example, would represent a different man or women. The species below each person would be the various reactants with which that specific header person could potentially react with, arranged according to unique chemical affinity preferences. Goethe believed these relations to exist in human life, owing to the fact that the logic of this affinity table chemistry was based on a well established law of nature.

Chapter four

See main: Chapter four

In the Goethe's 1809 Elective Affinities, people are described as chemical species whose amorous affairs and relationships were pre-determined via chemical affinities similar to the pairings of alchemical species. Goethe outlined the view that passion, marriage, conflict, and free-will are all subject to the laws of chemistry and in which the lives of human species are regulated no differently than the lives of chemical species. In the novella, the central chemical reaction that takes place is a double displacement reaction (double elective affinity), between a married couple Eduard and Charlotte (BA), at the end of their first year of marriage (for each their second marriage), and their two good friends the Captain and Ottilie (CD), respectively.

The first marriages, for both Eduard and Charlotte, are described as having been marriages of financial convenience, essentially arranged marriages. Specifically, when they were younger, Eduard was married off to a rich older women through the workings and insatiable greed of his father; Charlotte, likewise, when her prospects were none the best, was compelled or obliged to marry a wealthy man, who she did not love. In the fourth chapter, the characters detail the world’s first ever verbally-depicted human double displacement chemical reaction.

The chapter begins with description of the affinity map (reaction map) or ‘topographical chart’ as Goethe calls it. On this reaction map, we are told that on it ‘the features of the estate and its surroundings were clearly depicted, on quite a large scale, in pen and in different colors, to which the Captain had give a firm basis by taking trigonometrical measurements’. Next, to explain the reaction, we are told:

“‘Provided it does not seem pedantic,’ the Captain said, ‘I think I can briefly sum up in the language of signs. Imagine an A intimately united with a B, so that no force is able to sunder them; imagine a C likewise related to a D; now bring the two couples into contact: A will throw itself at D, C at B, without our being able to say which first deserted its partner, which first embraced the other’s partner.’”

This is shown below, in modern reaction terms:

$AB + CD \to BD + AC \,$

“‘Now then!’ Eduard interposed: ‘until we see all this with our own eyes, let us look on this formula as a metaphor from which we may extract a lesson we can apply immediately to ourselves. You, Charlotte, represent the A, and I represent your B; for in fact I do depend altogether on you and follow you as A follows B. The C is quite obviously the Captain, who for the moment is to some extent drawing me away from you. Now it is only fair that, if you are not to vanish into the limitless air, you must be provided with a D, and this D is unquestionably the charming little lady Ottilie, whose approaching presence you may no longer resist.’”

(add discussion)

Discussion
Although there have been dozens of argumentative papers published, being either for or against Goethe's use of chemical theory, one of the best was German historian Jeremy Adler's 1987 "Goethe’s Elective Affinity and the Chemistry of its Time", wherein he made educated guesses as to which chemist Goethe sourced during each scene or chapter.

References
1. (a) Adler, Jeremy. (1987). “Eine fast magische Anziehungskraft”. Goethe’s “Wahlverwandtschafte” und die Chemie seiner Zeit (“An almost Magical Attraction”). Goethe’s Elective Affinity and the Chemistry of its Time), Munich.
(b) Thims, Libb. (2007). Human Chemistry (Volume Two), (preview), (ch. 10: "Goethe's Affinities", pgs. 371-422). Morrisville, NC: LuLu.
(c) Smith, P.D. (2000). “Elective Affinity: a Tale of Two Cultures”, Prometheus, 46-65.
2. Swales, Martin and Swales, Erika. (2002). Reading Goethe: a Critical Introduction to the Literary Work (pg. 73). Camden House.