Descartes constructed as noble a road of science, from the point at which he found geometry to that to which he carried it, as Newton himself did after him. ... He carried this spirit of geometry and invention into optics, which under him became a completely new art.
I believe that there never was a creator of a philosophical system who did not confess at the end of his life that he had wasted his time. It must be admitted that the inventors of the mechanical arts have been much more useful to men that the inventors of syllogisms. He who imagined a ship towers considerably above him who imagined innate ideas.
All is a miracle. The stupendous order of nature, the revolution of a hundred millions of worlds around a million of stars, the activity of light, the life of all animals, all are grand and perpetual miracles.
It is the poverty connected with our species which subordinates one man to another. It is not inequality which is the real misfortune, it is dependence.