XXVII. ‘On this subject more words are needless here. Whatever you assume to be the effective cause of these vicissitudes and changes, it will hold each world together within itself. Each world has earth and sea, each has a middle point [Sidenote: 425] of its own, its own vicissitudes and changes of the bodies upon it, and a nature and a force which preserve everything and keep it in its place. As for what is outside, whether it be nothing or an infinite void, it presents no middle point, as we have said; while, if there be many worlds, each has a middle point of its own, and therefore a special movement of bodies to or from or about that middle (to follow the distinction made by these thinkers). To insist that, where there are many middle points, weights press from all sides to one, is as though we should insist that, whereas there are many men, the blood from all should flow together into a single vein, and the brains of all be enveloped in a single pia mater; and to make it a grievance [Sidenote: B] that all hard bodies in nature should not be together in one place, and all rarefied bodies in another. That would be preposterous, and equally so to complain that wholes should have their parts disposed in their natural order within each of them. It might be absurd to call that a world which has a moon low down[169] within it, like a man with his brain lodged in his ankles or his heart in his temples. But to make several independent worlds, and then to differentiate the parts in sets to follow their wholes, and so divide them, is not absurd. Earth, [Sidenote: C] sea, and heaven will be in their natural and proper arrangement within each. Above, below, around, middle have no relation to another world or to the outside, each world has them all in and for itself.