Vision, I say, is related to light itself. But of this sensation and the things pertaining to it, I pretend to understand but little; and since even a long time would not suffice to explain that trifle, or even to hint at an explanation, I pass over this in silence.

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual.

The greatest wisdom is to get to know oneself.

Being infinitely amazed, so do I give thanks to God, Who has been pleased to make me the first observer of marvelous things, unrevealed to bygone ages.

What ever the course of our lives, we should recieve them as the highest gift from the hand of God, in which equally reposed the power to do nothing whatever for us. Indeed, we should accept misfortune not only in thanks, but in infinite gratitude to Providence, which by such means detaches us from an excessive love for Earthly things and elevates our minds to the celestial and divine.

Mathematics is the key and door to the sciences.

E pur si muove. "Albeit It does move". (That's what Galileo purportedly muttered after torturers forced him to recant his theory that the earth orbits the sun.)