"The way to chastity is not to struggle directly with incontinent thoughts but to avert the thoughts by some employment, or by reading, or by meditating on other things."

"In the absence of any other proof, the thumb alone would convince me of God's existence."

"I build my philosophy upon the shoulders of giants."

"I have studied these things – you have not."

"The changing of bodies into light, and light into bodies, is very conformable to the course of nature, which seems delighted with transmutations."