The moon's size and the limits of human reasoning

The western sea, by contrast, undergoes its ebb tides, now receding and then flooding over again, as if drawn backward by the moon's exhalations and then pushed forward to its proper measure by her out-breathings. I have said these things to demonstrate the size of the lights and to establish that not even a syllable of the God-inspired words is idle. And yet my discourse has touched on almost none of the essential points. For those who have examined the workings and powers of the sun and moon with care can discover by reasoning a great deal about their sizes and distances. We ought, then, to accuse ourselves honestly of our own weakness, so that the greatest of created works are not measured by our own speech, but rather so that from the few things said we may reckon for ourselves how many and how great are the things left unmentioned.

Do not, therefore, measure even the moon with your eye, but with reasoning, which is far more accurate than the eyes for discovering truth. Some laughable myths, babbled everywhere by old women in their cups, have spread the claim that the moon is moved from her own seat by certain sorceries and brought down to the earth. How could a magician's incantation move her whom the Most High himself established? And what place could receive her if she were dragged down? Do you want to grasp the proof of her size from small indications? The cities throughout the inhabited world, though separated from one another by the greatest distances, all receive the moon's light equally in their streets turned toward the east. If she were not directly opposite them all, she would certainly illuminate those in the straight line of the narrow streets, but for those beyond her breadth she would cast her rays obliquely, slanting them to the sides. This is what one can see happening with lamps in houses. When several people stand around a lamp, the shadow of the one standing directly in front of it extends upright, while the remaining shadows incline to each side. So if the moon's body were not immense and surpassing in size, it would not extend equally opposite to all.

For when she rises from the equatorial regions, those who dwell in the frozen zone and lie beneath the turnings of the Bear receive her light just as those who live in the hollows of the south, neighbors of the scorched zone. Extending opposite to all of them across her breadth, she provides the clearest testimony of her size. Who, then, will deny that her body is enormous, matching such great and numerous distances at once? Let this suffice concerning the sizes of the sun and moon.

May he who granted us understanding to learn the great wisdom of the Craftsman from the smallest things of creation also grant us to receive from the great things even greater conceptions of the Creator. And yet, in comparison with the Maker, the sun and moon hold the rank of a gnat and an ant. For it is not possible to gain from these a vision worthy of the greatness of the God of all things, but only to be led forward by small and faint impressions through them, just as through each of the smallest things among animals or plants.

Let us be content with what has been said. I give thanks to him who granted me this small ministry of the word, and you to him who nourishes you with spiritual food—who even now has fed you, as with some barley bread, through the humble quality of our voice. And may he nourish you forever, granting you the manifestation of the Spirit according to the measure of your faith, in Christ Jesus our Lord, to whom be glory and power forever and ever.