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.
What is tolerance? It is the consequence of humanity. We are all formed of frailty and error; let us pardon reciprocally each other's folly - that is the first law of nature.
Our character is composed of our ideas and our feelings: and, since it has been proved that we give ourselves neither feelings nor ideas, our character does not depend on us. If it did depend on us, there is nobody who would not be perfect. If one does not reflect, one thinks oneself master of everything; but when one does reflect, one realizes that one is master of nothing
I have lived eighty years of life and know nothing for it, but to be resigned and tell myself that flies are born to be eaten by spiders and man to be devoured by sorrow.