Styles of Experimental Reasoning in Early Modern Chemistry

The science of chemistry has undergone two major transformative changes during the early modern period, both closely related to two of the most revolutionary episodes in the history of Western science. The dissertation consists of a historical-analytical comparative exploration of early modern chemical thought and practice based on two series of interconnected case studies related, respectively, to the seventeenth-century Scientific Revolution and the eighteenth-century Chemical Revolution. Although rarely considered together in the context of the history of chemistry, during both Revolutions, similar forces combined to generate crises in chemical knowledge and practice, to use a well-known Kuhnian notion. Differences in nature and historical evolution notwithstanding, both instances featured attempts at quantification and physicalist reductions of chemistry: during the 1660s-1680s Boyle advanced a reconciliation of chymical experimental knowledge with the budding mechanical philosophy, predicated upon the physically governed laws of matter and motion; during the last third of the eighteenth-century, Lavoisier (et al.) submitted chemical phenomena to the ‘rule of the balance’, as a part of an all-encompassing experimentalist, theoretical and linguistic reformation anchored in the conservation of weight principle. Concerned with the ‘losers’ (the chemists par excellence) rather than the ‘winners’, the study analyzes the reactions of leading contemporary chemists. Part I explores a critique of Boyle’s experimental philosophy and mechanist agendas conducted by French Royal Academician Samuel C. Duclos (1598-1685). In face of what he perceived as the unwarranted mechanical reduction of chymistry, Duclos set out to rehabilitate traditional chemical philosophy, drawing upon Paracelsian and Helmontian notions. This critique (1667-68) sparked a lengthy debate over cohesion and coagulation between academicians of diverging chymical and physical persuasions, culminating in the 1669 dispute over pesanteur and gravity. Part II examines Joseph Priestley’s and Richard Kirwan’s defenses of phlogistic chemistry and their respective versions of chemical experimentalism, followed by a broader contextualizing inquiry into the nature of the metaphysical, epistemological and rhetorical commitments that were defended under the banner of the phlogistic chemical worldview during the late stages of the Chemical Revolution. The category of Style of Experimental Reasoning (SER)—derived from A. C. Crombie and I. Hacking—is introduced, developed and used for capturing salient features of early modern chemical knowledge as it was dynamically molded at the confluence of discourse and practice. In contrasting contemporary chemists’ reactions to the physicalist challenges, the two revolutionary episodes mutually illuminate each other; the category of SER affords a reconstruction of the chemists’ unique realm of action and subsequent production of chemical knowledge. Inquiring into the dialectics of continuity-versus-discontinuity between the two perceived Revolutions, the study redraws the line between the ‘chymical’ and the ‘physical’, providing a new understanding of the metaphysical and experimental complexities involved in the birth of modern chemistry.

Advisor: Levere, Trevor