Although scholars have long recognized the importance of "elective affinity" as a key word in Weber's sociology, surprisingly little systematic research has gone into understanding this metaphor in Weber's writing, or the source from which he drew the term. For Weber, this was an implicit reference to Goethe's novel, well known to Weber's educated German audience, entitled Elective Affinities. In this article, I provide a systematic account of Goethe's conception of elective affinity as a chemical metaphor, and of the way (...) that it is related to Weber's uses of the term in the Protestant ethic essays and in his critical rejoinders. By understanding elective affinity as a Goethean chemical metaphor we can better understand the causal claims that Weber makes in his famous essay: Weber's argument is best understood as an analysis of emergence in the chemistry of social relations. (shrink)