XVI. This said, as I was passing the turn to Lucius, the [Sidenote: E] argument now reaching the stage of demonstration, Aristotle said with a smile: ‘I protest that you have addressed your whole reply to those who assume that the moon herself is half fire, and who say of all bodies in common that they have an inclination of their own, some an upward one, some a downward. If there is a single person who holds that the stars move in a circle according to Nature, and are of a substance widely [Sidenote: F] different from the four elements, it has not occurred to our memory, even by accident; so that I am out of the discussion, and you also, Lucius.’ ‘No, no, good friend’, said Lucius. ‘As to the other stars, and the heaven in general, when your school asserts that they have a nature which is pure and transparent, and removed from all changes caused by passion, and when they introduce a circle of eternal[330] and never-ending revolution, perhaps no one would contradict you, at least for the present, although there are countless difficulties. But when the theory comes down and touches the moon, it no longer retains in her case the “freedom from passion” and the beauty of form of that body. Leaving out of account her other irregularities and points of difference, this very face which appears upon her has come there either from some passion proper to herself or by admixture of some other substance. [Sidenote: 929] Indeed, mixture implies some passion, since there is a loss of its own purity when a body is forcibly filled with what is inferior to itself. Consider her own torpor and dullness of speed, and her heat, so faint and ineffectual, wherein, as Ion[331] says— _The black grape ripens not_; to what are we to assign this, but to weakness in herself and passion, if passion can have place in an eternal and Olympian body? It comes to this, dear Aristotle; look on her as earth, and she appears a very beautiful object, venerable and highly adorned; but as star, or light, or any divine or heavenly body, I fear she may be found wanting in shapeliness and grace, and do no credit to her beautiful name, if out of all the multitude in heaven she alone goes round begging light of others, as Parmenides says, [Sidenote: B] _For ever peering toward the sun’s bright rays._