Possibly the most influential thinker ever, Aristotle wrote on logic, nature, and physics, the origins of the Earth and universe, on species and much more. He was influential for centuries after the Greek civilization disappeared. At the time of Galileo most people still thought that Aristotle’s view of the universe was right.
He believed that the Earth was at the centre of the universe and the planets and stars were fixed in crystal spheres that moved around it. The word planet is Greek for wandering star.
Aristotle didn’t believe in experiment. He wrote; “what must logically be the case must be true.” With regard to falling objects, he said, that the speed an object falls at is proportional to its weight. So if you have a ball weighing 100g, and one weighing 1kg, the heavier one will fall ten times as fast. If he had experimented he would have realised his mistake.
