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.

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.

Spots are on the surface of the solar body where they are produced and also dissolved, some in shorter and others in longer periods. They are carried around the Sun; an important occurrence in itself.

The Divine intellect indeed knows infinitely more propositions [than we can ever know]. But with regard to those few which the human intellect does understand, I believe that its knowledge equals the Divine in objective certainty.

It is necessary for the Bible, in order to be accommodated to the understanding of every man, to speak many things which appear to differ from the absolute truth so far as the bare meaning of the words is concerned.

I do not feel obliged to believe that the same God who has endowed us with senses, reason, and intellect has intended us to forego their use.

Nature is written in mathematical language.