And as to the argument which some do draw from a stone supposed to be placed without the world, it neither proves rest nor motion; for how could it remain suspended, seeing it is by nature heavy, or move towards the midst of the world, as other ponderous bodies, seeing it is neither part of it nor like it? And as to that earth which is fixed and environed by another world, we must not wonder, considering its weightiness, if it does not drop down, seeing it is upheld by a certain natural force pertaining to it. For if we shall take high and low not within the world but without, we shall find ourselves involved in the same difficulties as Epicurus was when he made his little indivisible atoms to move and tend to those places which are under foot, as if the vacuum had feet, or its infinite space would permit one to talk of high or low. Indeed, a man would marvel what should cause Chrysippus to say, that the world was placed and situated directly in the midst, and that the matter thereof, from all eternity having possessed itself of the midst, yet is so compacted together that it remains for ever. For he writes this in his Fourth Book of Possible Things, vainly imagining there is a middle in that vast emptiness, and still more absurdly attributing unto that middle, which is not, the cause of the world’s stability and continuance; he having often said in other writings of his that the substance is upheld and governed, partly by the motions tending to the midst of it, and partly by others parting from the midst of it.