

Crystallizations as a form of scientific semantic change
the case of thermodynamics
pp. 209-230
in: Bernd-Olaf Küppers, Udo Hahn, Stefan Artmann (eds), Evolution of semantic systems, Berlin, Springer, 2013Abstract
When considering the diachronic structure of scientific disciplines, four ideal types of change in the semantic systems constituting them may be distinguished: (1) (normal) evolution; (2) (revolutionary) replacement; (3) embedding (of one conceptual system into another); and (4) (gradual) crystallization of a conceptual framework. In the literature on diachronic philosophy of science, the last type has been unduly neglected in spite of its great significance for understanding the history of science. It consists in a piecemeal but nevertheless fundamental change of the conceptual framework of a discipline during a relatively long period of time. In this paper, an attempt is made to characterize as precisely as possible what the general semantic features of crystallization are and to illustrate them by analysing the gradual emergence of phenomenological thermodynamics in the middle of the nineteenth century, in particular as due to the work of Rudolf J. Clausius between 1850 and 1854. The (formal-semantic) notion of classes of models as understood in the structuralist metatheory of science will be used for that purpose. Three different conceptual nets will formally be distinguished in Clausius's papers corresponding to as many steps in the crystallization of what is now known as (phenomenological) thermodynamics. The reconstruction makes explicit the way Clausius's concepts evolved during the historical period under consideration.