I would say here something that was heard from an ecclesiastic of the most eminent degree: The intention of the Holy Spirit is to teach us how one goes to heaven, not how the heavens go.

I have never met a man so ignorant that I couldn't learn something from him.

Their vain presumption of knowing all can take beginning solely from their never having known anything; for if one has but once experienced the perfect knowledge of one thing, and truly tasted what it is to know, he shall perceive that of infinite other conclusions he understands not so much as one.

Some, merely to contradict what I had said, did not scruple to cast doubt upon things they had seen with their own eyes again and again.

I, Galileo, son of the late Vicenzo Galilei, swear that I never said that the prime numbers are useless. What I said was that you cannot count lunar craters by counting 2, 3, 5, 7.

Oh, my dear Kepler, how I wish that we could have one hearty laugh together. Here, at Padua, is the principal professor of philosophy, whom I have repeatedly and urgently requested to look at the moon and planets through my glass, [telescope] which he pertinaciously refuses to do. Why are you not here? what shouts of laughter we should have at this glorious folly! and to hear the professor of philosophy at Pisa laboring before the grand duke with logical arguments, as if with magical incantations, to charm the new planets out of the sky.

Nothing can be taught to a man, only it's possibly to help him to discover it inside.