Learning is the only thing the mind never exhausts, never fears, and never regrets.

The eye encompasses the beauty of the whole world.

Blinding ignorance does mislead us. O! Wretched mortals, open your eyes!

The lie is so vile, that even if it were in speaking well of godly things, it would take off something from God's grace; and Truth is so excellent, that if it praises but small things they become noble.

It's easier to resist at the beginning than at the end.

If a man has a tent made of linen of which the apertures have all been stopped up, and be it twelve bracchia across (over twenty-five feet) and twelve in depth, he will be able to throw himself down from any height without sustaining injury. [His concept of the parachute.]

When you are painting you should take a flat mirror and often look at your work within it, and it will then be seen in reverse, and will appear to be by the hand of some other master, and you will be better able to judge of its faults than in any other way.