The Manichaean teaching about the Moon is impossible.

If, moreover, as they say, "the Moon receives the Light which is refined, and during fifteen days draws it up and goes on emptying it out for another fifteen days," if she is filled very gradually till the time of full moon, it may well be because there are not sufficient Refiners to give the Light at once, but why, pray, is it that she empties the Light little by little ? [Cf. pp. xxxviii. ll. 27, 127 ; xlii. 1. ll. P. 16.] Either the Receiving-Vessels do not receive and let it go at once, or the place into which she empties it is small and there is room for only a part daily. And while for fifteen days that Ship of Light seeks to empty out (the Light), where, pray, does that other Light, which is 'being refined and is going up,' go and collect and exist while the Moon is being emptied ? It must wander about and be lost for lack of a place to receive it; and so Darkness swallows it once more. [Cf. pp. xliv. 1.16; lxxxv. 1.4; lxxxix. l. 26.] For if it 'sucked in the Light' when it was far from it in the beginning, will it not gulp it down all the more, now that the Light exists at the very door of its mouth?