Flat Earth
If the Earth were flat then it'd be a lot easier for man to comprehend.
He cannot imagine himself sticking to the outside of a ball, like an ant, not really. He may imagine a theory where that's the case, but in the mind of man the Earth is flat, and not just because it seems flat from the surface.
Man always feels the tension between the limited and the infinite in his heart; if he goes in this direction forever does he hit a wall, a final extent which cannot be passed, or does he walk forever further, in a world without end?
Truly, though, man cannot tolerate the idea that the Earth on which he stands is both and neither of these.
He reaches the pole, a kind of final extent, only then to pass it and return to the mundane world; he goes on forever, but only in circles around a globe, frustrated, repeating himself endlessly.
And he cannot understand gravity. Yes, he may have a theory of it, but the lower reaches of his mind cannot hold such an idea.
When he takes to objects in his hand they are not drawn together, and so he thinks that only tangible forces can move objects. He knows that there is an up and down, but for things to move up is uncanny, even in the case of birds, and for things to move down is frightening, and sometimes thrilling, such as in the case of skiing.
But he does not call this downward movement "gravity", he calls it "falling", or "sliding". By gravity, he means that something has weight and is important, it feels heavy to him in his hands, but he does not feel the weight when the object is failing, he only feels shock.
But if a man does truly see himself as standing on a bright marble hanging on nothing then he is not free, he simply recreates the notion that he lives in a world which goes on far beyond his understanding.
It is possible that the universe has no edge, and yet the common conception is that it does, and that it must. Man sees all physical things as being finite, and when he starts to see physical things as being infinite then he begins to imagine what wonders lie far into that infinite place.
When he goes so far out to sea that he can no longer see the shore line then he enters the world of dragons, and he finds far shores which are filled with monsters, and fairies, and strange people.
In truth, a man who stands on the flat earth is more grounded, for he has divided the earth from the Deep below it, and the sky above it, and the sky above that.
The man who stands on the orb is a wizard, but he forms no clean divisions, and all of his frontiers roll into each other, and he is confused.
Where does the Deep go when he believes that he is standing on a ball made of rock and magma? How can he push away the dark abyss while keeping himself above it, and while remembering the tightrope he walks on above it?
A man with no abyss is a man without gravity, for there's nothing below him to drag him down. Instead his abyss becomes the cosmic forces beyond his ken, the forces which underpin his reality, and which he is apart from. When he looks to science, and into these cosmic forces then he feels that he looks into the abyss, that he becomes small in the face of the cataclysmic power of creation.
Gravity hurls objects through space like the ball on the end of a flail, and the learned man fears this, and that is his abyss.
But where does the man on the ball find his burning heavens, beyond his celestial sphere? Where is the realm of God, of seraphim, divine light, music, and beauty?
He cannot find it beyond his ball, for that is the realm of chaos and the unknown, and deep with in his ball is only mundane matter, and so he can only find his heavenly realm within himself.
But when he looks within, all he sees is blood, and guts, and unfulfilled longing.