Well...imagine dropping a cannonball and a feather from the top of a tower. Obviously the cannonball is going to hit the ground first. You can then extrapolate

Well...imagine dropping a cannonball and a feather from the top of a tower. Obviously the cannonball is going to hit the ground first. You can then extrapolate this result to heavier objects and conclude that heavier objects fall faster. To explain the behaviour of a small cannonball and a large cannonball, both of which fall to the ground almost at the same time: you see, as the weight of an object increases, an object starts to behave more and more like an extremely heavy object. Thus the difference in dropping time for a heavy object and a heavier object gets immeasurably smaller as the objects increase in mass. You can come up with all sorts of theories to explain phenomena. It's pretty hard to deduce the underlying rule from observation. But it's pretty easy to explain the phenomenon once you know the underlying rule.