Aristotle had an excellent answer to the question why do rocks fall when you drop them? Galileo proposed not a different answer or a better one, but no answer at all. People do not “know a thing until they have grasped the ‘why’ of it,” Aristotle insisted, but Galileo would have none of it. To ask why things happen, he declared, was “not a necessary part of the investigation.” And that change was only the beginning.
