Originally Posted by Botnst

Say for example there's a man in a box without windows. He suddenly finds himself thrown against the floor with great violence. After a time, he adjusts and it seems that stability is reached. Then suddenly he starts floating upward and suddenly he careens toward the ceiling. He finds himself flattend against the ceiling and then slowly struggles to his feet.

The hapless man things that maybe there is a machine outside of his box, like a giant magnet, pulling him this way or that. Or maybe somebody has his box on a bungie.

How can this man know the truth of his circumstances without having special knowledge of what's going-on outside of his closed box?