Chúng ta không thể dạy bảo ai bất cứ điều gì. Chúng ta chỉ có thể giúp họ phát hiện ra những gì còn tiềm ẩn bên trong con người họ. - Galileo Galilei

I have been in my bed for five weeks, oppressed with weakness and other infirmities from which my age, seventy four years, permits me not to hope release. Added to this (proh dolor! [O misery!]) the sight of my right eye — that eye whose labors (dare I say it) have had such glorious results — is for ever lost. That of the left, which was and is imperfect, is rendered null by continual weeping.

Among all the great men who have philosophized about this remarkable effect, I am more astonished at Kepler than at any other. Despite his open and acute mind, and though he has at his fingertips the motions attributed to the earth, he nevertheless lent his ear and his assent to the moon's dominion over the waters, to occult properties, and to such puerilities.

Of such are the mathematical sciences alone; that is, geometry and arithmetic, in which the Divine intellect indeed knows infinitely more propositions, since it knows all. But with regard to those few which the human intellect does understand, I believe its knowledge equals the Divine in objective certainty, for here it succeeds in understanding necessity, beyond which there can be no greater sureness.