we don't understand shyt about it. it's not law.....Youre reaching way too much..ok until the next genius superhuman that can find away to float up instead of falling to ground when they jump off a building then it's a theory..but out of the trillion times of shyt falling to the ground ..Gravity is a law..
it's stuff we think about it because we want to make 'facts' out of shyt falling from the sky like apples.
We don't know why it pulls things to massive objects like earth. We'd need to understand quantum theories yet.... plus We don't 'know' that gravity only pulls..... everything else pull , moves repeals.
The thin line of the creation of the universe is damn near proving an existence of a Creator ( imhO) . Gravity is Weak and fine tuned just right so that everything can exist. But we don't know why
http://www.newscientist.com/article/mg20227123.000-gravity-mysteries-why-is-gravity-finetuned.html
Plus we don't know that gravity 'works', every time. We just think it does.
So Gravity is both a law and theory (as @Type Username Here said) ---- We know somethings happening (law) but we don't know why or how its happening (but we have theories)