How to investigate the underpinnings of sciences? The case of the element chlorine

Abstract

In recent publications, Harre and Llored (in: Javenovic (ed) Challenges of cultural psychology, Routledge, London, pp 189–206, 2018a; Philosophy, 93:167–186, 2018b; The analysis of practices, Cambridge Scholars Publishing, Newcastle upon Tyne, 2019) take the role of philosophy of science as a digging out of the ‘hinges’, that are the tacit elements of a discipline. In this perspective, the philosophy of chemistry consists, at least partly, in making explicit the hinges on which chemistry turns and in examining their origins and logical status. In this paper, we propose to query Harre and Llored’s research approach in the case study of the element chlorine. Whereas most early nineteenth-century textbooks define the element as the endpoint of chemical decomposition, the controversy surrounding the element chlorine reveals implicit criteria that surpass operational indivisibility. From 1810 onwards, Davy argued that chlorine was a simple substance; yet, even though it had been known to be indecomposable using the strongest instruments available, the widespread acceptance of chlorine took until 1816–1818. The main factor that contributed to the resolution of the debate was the discovery of iodine, an analogous element which provided new theoretical coherence between explanations of different phenomena (Chabot, in: Du nouveau dans les sciences. Groupe rech. philos. langag., Universite des sciences sociales de Grenoble, St-Martin-d’Heres, pp 121–169, 2006; Golinski in Science as public culture: chemistry and enlightenment in Britain, 1760–1820, Cambridge University Press, New York, 1992; Gray et al. in An element of controversy: the life of chlorine in science, medicine, technology and war, British Society for the History of Science, London, pp 41–72, 2007; Siegfried in Isis 54(2):247–258, 1959). Thus, the idea that elements should qualitatively resemble each other is an implicit belief which appears to have been shared by many prominent chemists of the time, despite the fact that it was not stated as part of the definition of the chemical element. Could we assert that this idea was a ‘hinge’ around which the notion of chemical element revolved? Our talk will answer this question.