Models and Mechanisms

This chapter analyzes the role of mechanical modeling in nineteenth-century physics, showing how precisely mechanical models were used to enhance scientific understanding. It discusses the work and ideas of William Thomson (Lord Kelvin), James Clerk Maxwell, and Ludwig Boltzmann, who advanced explicit views on the function and status of mechanical models, in particular, on their role in providing understanding. A case study of the construction of molecular models to explain the so-called specific heat anomaly highlights the role of conceptual tools in achieving understanding and shows that intelligibility is an epistemically relevant feature of mechanical models. Next, the chapter examines Boltzmann’s Bildtheorie, an interpretation of mechanical models that he developed in response to problems and criticisms of the program of mechanical explanation, and his associated pragmatic conception of understanding. The final section discusses the limitations of mechanical models and Ernst Mach’s criticism of the mechanical program.