Conventionalism and the Origins of the Inertial Frame Concept

This paper examines methodological issues that arose in the course of the development of the inertial frame concept in classical mechanics. In particular it examines the origins and motivations of the view that the equivalence of inertial frames leads to a kind of conventionalism. It begins by comparing the independent versions of the idea found in J. Thomson (1884) and L. Lange (1885); it then compares Lange's conventionalist claims with traditional geometrical conventionalism. It concludes by examining some implications for contemporary philosophy of space and time.