Ghosts masquerading as truths

In Zen and the Art of Motorcycle Maintenance, Robert  Persig has his main character, at one point in the story, discuss the irony of modern westerners mocking Native American cultures for their beliefs in the supernatural, even ghosts.  He goes on to say that many of our scientific beliefs are or have actually been just that: beliefs.

Gravity is the example he used.  He mentioned, in particular, the Law of Gravity, and the fact that the concept of gravity did not really exist in the human mind before the law became "fact."  Certainly, humans knew that they were not drifting around aimlessly prior to this pronouncement, but they also believed that the Earth, somehow, was at the center of all existence, and that God's universe was constructed around this nucleus.  After various discoveries, not the least of which were those of Copernicus and Columbus, those ghosts were exorcised.  The paradigm shift was immense.  The scope of the Earth and the universe exploded in the human mind, setting off the Enlightenment, the Age of Reason, and a whole new deluge of mental ghosts.

Today, the question seems to be: "Is gravity pulling us to the planet, is the large mass drawing smaller masses towards its center, or is the universe pushing us down to it?"  Einstein theorized that gravity was not a force at all, that it was rather an illusion caused by the space-time continuum.  What is the difference to us?

I know that when I jump, I expect to come back down, firmly on terra firma.  When Matthew Stafford throws a bomb to Megatron, he, after many years of preparation and repetition, launches the football skyward to a space high in the air.  His mind, even his arm "knows" how much force to apply to the pass, what trajectory to launch it on, and what point the ball will likely approach the Earth again.  What does Matthew Stafford know about gravity in this case?  He knows, intuitively, how to manipulate the ball in such a way that he can use gravity to his advantage.  He uses no equations, no formulas, no slide-rules.  His mind - and mind you, I think the entire body is mind, since neurons permeate every fiber of us - does all of these calculations intuitively.  Muscle memory knows when to squeeze the ball a little harder, when to shift the weight on his feet, and at what point in the throwing arc the ball should be released to achieve the desired result.

So, what do we know?  Gravity is a multifaceted concept, viewable from the perspectives of a number of different paradigms.  In the end, we know, mostly, what goes up must come down.  But why?