Sadi Carnot: Misunderstood for Two Hundred Years

The overall theme is that for two hundred years Sadi Carnot’s 1824 essay has been misunderstood. Carnot’s reasoning has been misrepresented by the dominant mechanistic formulation of the Clausius, Boltzmann, Gibbs tradition. To understand the origin and nature of the misunderstanding it is necessary to recognize that there are the two histories and two current formulations of thermodynamics: the mechanical and the engineering. Both these formulations turn out to have a long history. In examining three historic periods, one just before Sadi wrote. A second period 1650-1750 centered on Huygens and Leibniz. The third period reaches back to the ancient Greek geometers, symbolized in Archimedes’ method. Atkins pointed out that there were two histories of thermodynamic, Boltzmann’s and Carnot’s. These have much longer histories in the Analytic and Synthetic Traditions. Two subthemes run throughout my inquiry helping to distinguish and clarify the two research programs. First are their different ontologies: particles versus metabolic engines. Second is their different perspectives on inquiry itself. The mechanical adopts a detached spectator perspective while the engineering has the perspective of a participant inside reality. Adrian Bejan’s recent recovery of engineering thermodynamics provides both clues and substance pointing to the proper understanding of Carnot’s essay.