The Gods did not reveal, from the beginning, all things to us, but in the course of time through seeking we may learn & know things better. But as for certain truth no man knows it, nor shall he know it, neither of the Gods nor yet of all things that I speak. For even if by chance he were to utter The Final Truth, he would himself not know it: for all is but a woven web of guesses.
XenophanesThis upper limit, of earth at our feet is visible and touches the air, but below it reaches to infinity
Xenophanes