The laws of nature are written by the hand of God in the language of mathematics.

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.

You cannot teach a person something he does not already know, you can only bring what he does know to his awareness.

The greatest wisdom is to get to know oneself.

In regard to the philosophers, if they be true philosophers, i.e., lovers of truth, they should not be irritated that the earth moves. Rather, if they realize that they have held a false belief, they should thank those have shown them the truth; and if their opinion stands firm that the earth doesn't move, they will have reason to boast than be angered.

They who depend upon manifest observations will philosophize better than those who persist in opinions repugnant to the senses.

Nature is relentless and unchangeable, and it is indifferent as to whether its hidden reasons and actions are understandable to man or not.