Lumen de Lumine

We are now to speake of the Aether of the little world, which is the very same in Nature and substance with the outward Aether of the great world. That you may the better understand what it is, we will examine the Notion, before we state the thing. Aristotle in his Book de Mundo derives this word ἀπὸ τὸ ἀεὶ θεῖν, à semper currendo, because the Heavens are in perpetuall Motion. This is a generall irregular whymzie, for the stars also aswell as the Aether move perpetually: The Sea is subject to a continuall Flux and Reflux, and the Bloud of all Animals to a restlesse unwearied Pulse. The more ancient Philosophers whose Books this Enemy burnt, derived it from αἴθω ardeo: but especially Anaxagoras, who was better acquainted with Heaven than Aristotle, as it appears by his miraculous praediction, and the opinion he had of that place, namely that it was his Country, and that he was to return thither after death. Indeed this last Etymologie comes neer the nature of the thing, for it is a Heating cheerishing spirit, but in its genuine Complexion it burns not. I cannot then approve of this latter Derivation no more than of the former: I rather believe that Aether is a Compound of ἀεὶ and θέρω, this substance being called Αἰθὴρ from its effect and office, ἀπὸ τῷ ἀεὶ θέρειν, à semper Calefaciendo.