De Plantatione

For it was fitting that the most perfect and greatest of all works should be made by the greatest of all makers; and it would not have been the most perfect of works if it had not been filled up by perfect parts, so that this world consists of all earth, and all water, and all air, and all fire, not a single particle, no not the smallest imaginable atom, being omitted.

It follows therefore of necessity, that what is outside must either be a vacuum or nothing at all. If now it is a vacuum, than how can that which is full and solid, and the heaviest of all things, avoid being pressed down by its own weight, since there is no solid thing to hold it up? from which consideration it would appear to be something like a vision, since the mind is always seeking for some corporeal foundation, such as everything which is moved, must of necessity have: and especially the world, inasmuch as it is the greatest of all bodies, and embraces a multitude of other bodies as its own appropriate parts.