"Nor do I doubt that learned and skillful mathematicians will agree with me if they are willing to give not superficial but profound attention to the arguments I adduce in this work."

"I consider the planets themselves to be divine, living creatures."

"The spheres of the planets do not revolve about the earth as their center, but about the sun."

"For the universe, wrought for us by a supremely good and orderly Creator, is from the very start constructed with the very best and most beautiful design."

"For it is manifest that the movements of the planets are not uniform, but sometimes faster, sometimes slower, sometimes direct, sometimes retrograde."