Thomson, Stokes, Rankine, and Thomson and Tait
Maxwell viewed his contributions to electromagnetism in the context of the work of his immediate predecessors and was often explicit about his sources of inspiration. We therefore turn our attention to a few physicists who made methodological claims to which Maxwell explicitly responded. We analyze the methodological contributions of four prominent physicists which serve as background to Maxwell’s study of electromagnetism: (1) Thomson’s formal analogy between physical systems; (2) Stokes’s concept of jelly which offers an analog to the ether with jelly as an idealization for facilitating mathematical treatment; (3) Rankine’s energeticist program; and, finally, (4) Thomson and Tait’s novel approach to Newtonian mechanics which served as the immediate background to Maxwell’s Treatise of electricity and magnetism (1873). To be sure, Maxwell was well aware of the contributions of other physicists, but he did not respond to their methodologies. Maxwell did not restrict himself to Thomson’s conservative practice, for he moved to a mathematical analogy in which one domain was imaginary; he thus modified Thomson’s conception of analogy; at the same time, Maxwell distanced himself from Stokes’s usage of idealization, a limiting argument, which was too restrictive for Maxwell’s purposes. Maxwell adopted Rankine’s conception of energy within the framework of electrodynamics, and he applied Thomson and Tait’s methodology of “abstract dynamics” to electromagnetic phenomena. Maxwell responded creatively to his sources, transforming their methodologies to suit his commitments and goals. Our interest is limited to the actual practice of physics, and not to general philosophical debates (e.g., Whewell vs. Mill).