About Isaac Newton
His 1687 book *Philosophiæ Naturalis Principia Mathematica* unified physics and founded classical mechanics. Newton also did important work in optics and, together with Gottfried Wilhelm Leibniz, developed infinitesimal calculus. He helped refine the scientific method, and his ideas are seen as a key part of the Scientific Revolution and the Enlightenment.
![“The best and safest way of philosophising seems to be, first to enquire diligently into the properties of things, and to establish those properties by experiences [experiments] and then to proceed slowly to hypotheses for the explanation of them. For hypotheses should be employed only in…” quote by Isaac Newton](https://sms4smile.com/q/img-quotes/943/isaac-newton-1226_employed_the-best-and-safest-way-of-philosophisin_2816749.jpg)
![“[1.] And first I suppose that there is diffused through all places an aethereal substance capable of contraction & dilatation, strongly elastick, & in a word, much like air in all respects, but far more subtile. 2. I suppose this aether pervades all gross bodies, but yet so as to stand rarer in…” quote by Isaac Newton](https://sms4smile.com/q/img-quotes/11c/isaac-newton-1226_air_1-and-first-i-suppose-that-there-is-diff_2720566.jpg)
