Newton, Hooke and priority over the inverse square

The publication of the Principia in 1687 was marked by a long, bitter priority dispute with Robert Hooke. Already in 1679 Hooke had written to Newton suggesting that the gravitational force might decrease as $1/r^2$, but without managing to derive Kepler’s elliptical orbits from it. The complete derivation — that the orbits of a $1/r^2$ field are conic sections — came only with Newton (1684), prompted by Edmond Halley. Hooke demanded recognition for the original hypothesis; Newton, furious, threatened not to publish the third volume of the Principia (Dolnick 2011).

Intuiting and proving

The dispute illustrates a recurring mechanism in science: intuiting a law and proving it are two qualitatively different things. Hooke had the $1/r^2$ intuition; Newton built the mathematics to deduce every observable trajectory from it. It is the difference, today, between a “good idea on a whiteboard” and a “predictive theory.” Halley, in the middle, acted as mediator and paid out of his own pocket for the printing of the Principia.

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Topics: Gravitazione Concepts: Legge di gravitazione universale

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