Changes

Newton’s education at Cambridge was classical, focusing on Aristotelian rhetoric, logic, ethics, and physics. Bound to Aristotelian scholasticism by statutory rules, [[CiteRef::Christianson (1984)|p. 33]] the curriculum had changed little in decades, despite the incompatibility of Aristotelian natural philosophy with Copernican heliocentrism [[CiteRef::Westfall (1980)|p. 81-90]][[CiteRef::Smith (2009)]] Like many of the more ambitious students, Newton is known to have distanced himself from classical metaphysics and instead studied the works of the French natural philosopher [[René Descartes]](1596-1650) on his own. By 1664, Newton is known to have read the 1656 Latin edition of Descartes' ''Opera philosophica'', a one volume compilation which included ''Meditations on First Philosophy'', ''Discourse on Method'', ''Dioptrics'', and ''The Principles of Philosophy'Descartes'major works. [[CiteRef::Smith (2009)]] Descartes had died just over a decade prior, and his major these works had first been published within the preceding thirty years. They were gaining in popularity and by about 1680 would become the [[Theory Acceptance|accepted]] centerpiece of the Cambridge curriculum, as they also would in Paris by 1700. [[CiteRef::Barseghyan (2015)|p. 190]]

Both Newton’s physics and philosophy were heavily influenced by Descartes’ ideasand were a challenge to what had by then become the Cartesian orthodoxy. Descartes' '''mechanical natural philosophy''' was derived from ancient Greek atomism. He was the most prominent member of a community of '''corpuscularist''' thinkers, who maintained that visible objects were made of unobservably tiny particles, whose relations and arrangement were responsible for the properties of visible bodies. Particles influenced one another only by direct physical contact, which was the cause of all motion, and ultimately all change. [[CiteRef::Disalle (2004)]] Aristotle had explained the properties of visible bodies in terms of their form, rather than in terms of the arrangement of their constituent parts. He maintained that heavy objects, composed of the element earth, tended towards their natural place; the center of the universe. The concept of a sphere of earth at rest in the center of the universe was central to Aristotle's entire cosmology. Motion in the terrestrial and celestial realms were seen as fundamentally different.[[CiteRef::Bodnar (2016)]] Descartes' theories explained gravity as due to a swirling vortex of particles around the Earth, which pushed things towards its center. Celestial motions were not different in kind. In accord with Copernican heliocentrism, Descartes posited that a larger vortex surrounded the sun, with the smaller planetary vorticies caught in a larger solar vortex [[CiteRef::Garber (1992)]][[CiteRef::Disalle (2004)]]. In Newton's time, major champions of the mechanical natural philosophy included Christiaan Huygens (1629-1695) and Gottfried Wilhelm Leibniz (1646-1716), who was to become a major rival of Newton's. By the time Newton published his magnum opus, ''Philosophiae Naturalis Principia Mathematica'' (''Mathematical Principles of Natural Philosophy'')in 1687, Descartes' views had been accepted at Cambridge. The title of Newton's work suggests he intended it to be in dialog with Descartes' ''Principia Philosophiae'' (''Principles of Philosophy'') published in 1644. Newton contested Cartesianism as the orthodoxy he sought to overturn.

Descartes saw the ultimate justification of knowledge claims to lie with human reason and the absence of doubt. He relied on classical methods of theorizing and conjectured hypotheses in order to construct scientific propositions.[[CiteRef::Janiak (2016)]] Such a '''rationalist''' approach to knowledge was also championed by Baruch Spinoza (1632-1677), Nicolas Malebranche (1638-1715), and by Gottfried Wilhelm Leibniz. [[CiteRef::Lennon (2014)]] In But, by the early 17th century , Galileo Galilei and Robert Boyle (1627-1691) had already begun to elaborate and practice an experimental approach to knowledge. Much of Newton's natural philosophy was adapted from Descartes' views, but Newton he was skeptical of Descartes' rationalism and rejected his method of hypotheses outright.[[CiteRef::Janiak (2016)]] Instead, his epistemological views drew from Galileo and Boyle and were similar to those of his contemporary and friend John Locke (1632-1704), who maintained that all knowledge came from experience. [[CiteRef::Rogers (1982)]]