We see only the simple motion of descent, since that other circular one common to the Earth, the tower, and ourselves remains imperceptible. There remains perceptible to us only that of the stone, which is not shared by us; and, because of this, sense shows it as by a straight line, always parallel to the tower, which is built upright and perpendicular upon the terrestrial surface.
Galileo GalileiTheir 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.
Galileo GalileiI 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.
Galileo GalileiWith regard to matters requiring thought: the less people know and understand about them, the more positively they attempt to argue concerning them.
Galileo Galilei