Aristotle's gravity "theory" survived unchallenged for TWO MILLENNIA because apparently nobody thought to drop two different objects from a height and watch what happens. Galileo finally did the experiment around 1590 and was like "um, guys, they hit the ground at the same time." The scientific method was clearly on backorder for 2,000 years! Though to be fair, without YouTube to post their results, how would ancient scientists get those sweet validation likes?