O conceito de éter nos trabalhos de Isaac Newton

Abstract

Designed by Aristotle (4th century BC) as a kind of subtle raw material matter, ether would be the "fifth element" which, besides being at the origin of the four elements of nature, would have generated the immutable and perfect celestial bodies. As well known, several of the earlier theories on the constitution of matter already refer to something similar to ether. However, it is in Aristotelian cosmology that this imponderable and subtle matter receives its own contours, from this; it occupies a very special position in future studies and debates, throughout the centuries. Even experiencing many changes, the ether did not disappear, not even when new insights on matter and the cosmos become frequent, especially during the first modernity. Particularly centered in the 17th Century, this dissertation focuses on Sir Isaac Newton (1642-1727), because there are clear indications that this outstanding scholar has introduced many modifications to his ideas about the ether, according to the phase of his works. In order to better verify these modifications, a small sample of the Newtonian writings, which point in this direction, is analyzed here. The selection of these writings was supported by an extensive historiographical review, and covers, particularly, the beginning of Newton's career and the phase in which he developed Optics, when his more mature version of ether appears to emerge