A circumstance which has always appeared wonderful to me, is that such sublime discoveries should have been made by the sole assistance of a quadrant and a little arithmetic.
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.
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.
Every one should be his own physician. We ought to assist, and not to force nature. Eat with moderation...Nothing is good for the body but what we can digest. What medicine can procure digestion? Exercise. What will recruit strength? Sleep.
It requires twenty years for a man to rise from the vegetable state in which he is within his mother's womb, and from the pure animal state which is the lot of his early childhood, to the state when the maturity of reason begins to appear. It has required thirty centuries to learn a little about his structure. It would need eternity to learn something about his soul. It takes an instant to kill him.