Motion in Renaissance Science

Abstract

Aristotle’s ideas, and interpretations of them, dominated theorizing about motion during the Middle Ages. However, local motion [motus localis] or locomotion was, according to the “philosopher” and his followers, only one of four types of change. In addition to change in location, the Peripatetics distinguished change in substance, in quality, and in quantity. Within these four domains of change, change always requires the existence of a potentiality which can be actualized. During the late renaissance, however, the peripatetic views on motion were variously criticized, adapted, rejected, and replaced (Bodnar 2016). Generally speaking, the different kinds of change were all reduced to local motion, and one of the key ideas of the new theory of motion was the principle of inertia. First versions of this concept were introduced by Galileo (1564–1642) and later developed by René Descartes (1596–1650) and Isaac Newton (1643–1727). The seeds of this (r)evolution, though, had already been planted by philosophers such as Johannes Buridanus (c. 1300–1358) during the late Middle Ages, who was himself inspired by the work of John Philoponus (c.490–c.570).

In the geocentric cosmos as conceived of by Aristotle (384–322 BC) and Ptolemy (c.100–c.170), there was a strict, ontological distinction between the sublunary world of change and the celestial world of perfect bodies making perfect, circular motions. However, in 1543, Copernicus (1473–1543) published his De revolutionibus which presented a heliocentric model of the universe, supported by Galileo’s telescopic observations. The collapse of the traditional worldview was completed when Newton introduced his notion of universal gravitation.