On these points it is not necessary to discourse any longer in this place. For whatever cause a man supposes shall produce such passions and changes, that very cause will contain each of these worlds in itself; because each of them has its sea and land, each its proper middle, and each its passions and change of bodies, and the nature and power which contain and preserve each in its place and being. For that which is without, whether it be nothing at all or an infinite vacuum, cannot allow any middle, as we have already said. But there being several worlds, each has its proper middle apart; so that in each of them there will be motions proper to bodies, some tending down to the midst, others mounting aloft from the midst, others moving round about it, according as they themselves do distinguish motions. And he who asserts there are many middles, and that heavy bodies from all sides do tend unto one alone, is like to him who shall affirm that the blood of several men runs from all parts into one vein, or that all their brains should be contained within one and the same membrane; supposing it absurd, that all natural bodies which are solid should not be in one place, and the rare in another. He that thus thinketh is certainly a mean philosopher; and no better is he who will not allow the whole to have all parts in their order, rank, and natural situation. What could be more foolish, than for a man to call that a world which had a moon within it so situated, as if a man should have his brains in his heels, and his heart in his forehead? Whereas there is no absurdity or inconveniency, if, in supposing several distinct worlds separated from one another, a man should distinguish and separate their parts. For in each of them the earth, sea, and sky will be placed and situated in their proper places, and each of these worlds may have its superior, inferior, circular, and middle part, not in respect of another world, nor in reference to what is without, but to what is within itself.