Volume 7, Issue 1, Spring 2018
The Mathematization of Natural Philosophy between Practical Knowledge and Disciplinary Blending
Descartes and Roberval
The Composite Pendulum and its Center of Agitation
This paper deals with Descartes’s and Roberval’s attempts to devise and describe the center of agitation of a composite pendulum. This episode has received some attention in the recent literature. It is usually depicted as the first step in the development of a general procedure for establishing the center of oscillation of a pendulum. My aim is to explore the different physical concepts and assumptions which informed the two mathematical accounts of the composite pendulum. I will argue that force, agitation, heaviness, or resistance of air essentially meant different things for Descartes and Roberval. As a result, the physical phenomena covered by the two geometrical procedures were quite distinct, and both mathematicians envisaged different roles of these phenomena within their agenda of studying nature.