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 the persecutors declare against each other mortal war, while the philosopher, oppressed by them all, contents himself with pitying them.

We are astonished at thought, but sensation is equally wonderful.

The longer we dwell on our misfortunes, the greater is their power to harm us

"I have no more than twenty acres of ground," he replied, "the whole of which I cultivate myself with the help of my children; and our labor keeps off from us the three great evils - boredom, vice, and want."

He was my equal in beauty, a paragon of grace and charm, sparkling with wit, and burning with love. I adored him to distraction, to the point of idolatry: I loved him as one can never love twice.

True power and true politeness are above vanity.