whence does the world receive its nutriment?

aristotle says that, if the world be nourished, it will likewise be dissolved; but it requires no aliment, and will therefore be eternal. plato, that this very world prepares for itself a nutriment, by the alteration of those things which are corruptible in it. philolaus affirms that a destruction happens to the world in two ways; either by fire failing from heaven, or by the sublunary water being poured down through the whirling of the air; and the exhalations proceeding from thence are aliment of the world.