When Newton writes that the apple and the Moon “fall” in the same way, he is saying something philosophically explosive. For two thousand years, from Aristotle onward, the physics of the heavens had been considered different in nature from that of the Earth: celestial bodies were made of pure ether, eternal, incorruptible, moved by divine intelligences; earthly bodies of coarse, mortal matter, subject to decay and rectilinear motion.
Newton, in a single stroke, abolishes this distinction: one mathematical law governs domestic falls and cosmic orbits alike. The sky is “made earthly.” It is perhaps the first time in the history of Western thought that a single formula, the same , claims to hold everywhere in the universe: an act of daring that we now take for granted, but which required Newton years of caution before committing it to print in the Principia (Newton 1687; Dolnick 2011).
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Topics: Gravitazione Concepts: Legge di gravitazione universale
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