Theory Choice in the Seventeenth Century: Robert Boyle Against the Paracelsian Tria Prima

Abstract

This is a postprint version of chapter 3 in E. Tobin and C. Ambrosio (eds.), Theory Choice in the History of Chemical Practices, SpringerBriefs in History of Chemistry, 2016. Robert Boyle's famous Sceptical Chymist (1661) is a dialogue on matter theory, between a Peripatetic Aristotelian (Themistius), a Chymist (Philoponus) and a Sceptic (Carneades), and moderated by a supposedly impartial individual (Eleutherius). At first glance, the book seems to offer an ideal case in which to study theory choice. Boyle introduces at least three types of competing theories of matter: the four-element theory of Aristotle, the three-principle theory of Paracelsus and the atomistic theory. In fact, the discussion actually focusses on one system only, the Paracelsian theory of the 'three principles' of Sulphur, Mercury and Salt, also referred to as the tria prima. The promise of theory choice between three competing systems hence thwarted, a more fruitful avenue of research is to analyse the book from the point of view of a mitigated type of theory choice, that between acceptance of the tria prima theory or its rejection and exploration of other theories. History of Science, Jan Baptist van Helmont, Robert Boyle, History of Chemistry, and History of alchemy