Lo spazio non è immobile. Cosmologia, meccanica e metafisica in Christiaan Huygens

(Space Is Not Motionless: Cosmology, Mechanics, and Metaphysics in Christiaan Huygens)

Abstract

Christiaan Huygens’ scientific work (1629-1695) is situated in the period between Galileo and Descartes on the one side and Leibniz and Newton on the other. He was the greatest geometrician of his times and also gave an extraordinary impulse to mechanics both with his discovery of the laws of collisions, centrifugal force, and the brachistochrone curve (or curve of fastest descent) and with his revolutionary considerations on various foundational physical concepts. In this essay, the author tackles Huygens’ examination of the notion of space, which is marked by a form of relativism much more radical than Lebiniz’s. Through a rigorous application of Galileo’s principle of non-influence of common motion, Huygens reaches a definition of physical space as an infinite entity in which there are neither privileged directions nor absolute places. Through this path, in his later years he reaches a highly original explanation for circular forces, and elaborates a relativistic mechanics that, albeit mostly unpublished, anticipates in a surprising manner the criticisms moved again to Newton by Ernst Mach only two centuries later.