16. These things being said, as I was giving Lucius his turn to follow and continue the discourse,—there being nothing left to be added but the demonstrations of this doctrine,—Aristotle smiling said: I am a witness, that you have directed all your contradictions and all your refutations against those who, supposing the moon to be half fire, affirm in general that all bodies do of their own accord tend either upwards or downwards; but if there is any one who holds that the stars have of their own nature a circular motion, and that they are of a substance wholly different from the four elements, you have not thought of saying any thing, so much as accidentally or by the way, against him; and therefore I am wholly unconcerned in your discourse. Indeed, good sir, said Lucius, if you should suppose the other stars, and the whole heaven apart, to be of a pure and sincere nature, free from all change and alteration of passion, and should bring in also a circle, in which they make their motion by a perpetual revolution, you would not perhaps find any one now to contradict you, though there are in this infinite doubts and difficulties. But when the discourse descends so far as to touch the moon, it cannot maintain in her that perfection of being exempt from all passion and alteration, nor that heavenly beauty of her body. But to let pass all other inequalities and differences, the very face which appears in the body of the moon necessarily proceeds from some passion of her own substance or the mixture of another; for what is mixed suffers, because it loses its first purity, being filled by force with that which is worse. Besides, as for the slowness and dulness of her course, her feeble and inefficacious heat, by which, as Ion says, The black grape comes not to maturity, to what shall we attribute them but to her weakness and passion, if an eternal and celestial body can be subject to passion? In brief, my friend Aristotle, if the moon is earth, she is a most fair and admirable thing, and excellently well adorned; but if you regard her as a star or light or a certain divine and heavenly body, I am afraid she will prove deformed and foul, and disgrace that beautiful appellation, if of all bodies, which are in heaven so numerous, she alone stands in need of light borrowed of another, and, as Parmenides has it, Looks always backwards on the sun’s bright rays.