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The evolution of the concept of cycle: from common sense to method of reasoning and calculation

Raffaele Pisano

Group of History of the Physics - Department of Physical Sciences - University of the Studies in Naples "Federico II°"

Abstract

What was a cycle before its introduction in the Réflexions sur the Puissance Motrice du Feu of Sadi Carnot? And still before the birth of Volta's Pile?
It's known that Aristotle only considered perfect the motions that were closed, or rather, those orbital of the planets. The Copernican point of view will confine the concept of cycle to the only common knowledge and geometric calculations, (i.e.) regarding number and the quadrature of the circle. Later, the concept of cycle appears (again) in the History of Science when, a young Italian scientist, A. Volta, proposed an electric cyclical path: a physical instruments called "electric artificial organ" (1799) - known today as Volta's Pile (column's effect).
Here, I will show as the concept of cycle will evolve to become the principal instrument of theory; further than becoming the original method of arguing, in the (case-study of the) thermodynamics of Sadi Carnot (1824): thermal machine cycle and synthetic method. In order to show this, it is necessary to explain why Sadi Carnot uses curiously the sentence "to suppress the adiabatic" when he considers his cycle. And I will mention the point of view of Lazare Carnot's synthetic method: he used it - in the case of the analysis (mathematics, XVIII cent) - as an original technical arguing that) gives an alternative instrument of study; in Réflexions, Sadi Carnot used it both calculation analytical method and method of arguing. In the end, I will consider other applications of the synthetic method and I will draw a general table of all these applications in the Réflexions. Therefore, the case-study of Sadi Carnot, shows the first concrete passage (in the History of the Science) of the concept of cycle, from tied up concept to the common concept of knowledge on which to theorize scientifically.
  I will conclude this writing adding other applications of the cycle that, by means of synthetic method, show as Sadi Carnot problem theory regarding the closing cycle has a clear solution.

Pisano R.: "The evolution of the concept of cycle: from common sense to method of reasoning and calculation", in Proceedings of I.P.E. Congress, Common Sense and Philosophy of Science, Naples, 2002, in press