35 Men worthy to be remembered in the study of philosophy, who have been raised by your praises to its highest place, declare, with commendable earnestness, as their conclusion, that the whole mass of the world, by whose folds we all are encompassed, covered, and upheld, is one animal possessed of wisdom and reason; yet if this is a true, sure, and certain opinion, they also will immediately cease to be gods whom you set up a little ago in its parts without change of name. For as one man cannot, while his body remains entire, be divided into many men; nor can many men, while they continue to be distinct and separate from each other, be fused into one sentient individual: so, if the world is a single animal, and moves from the impulse of one mind, neither can it be dispersed in several deities; nor, if the gods are parts of it, can they be brought together and changed into one living creature, with unity of feeling throughout all its parts.
The moon, the sun, the earth, the ether, the stars, are members and parts of the world; but if they are parts and members, they are certainly not themselves living creatures; for in no thing can parts be the very thing which the whole is, or think and feel for themselves, for this cannot be effected by their own actions, without the whole creature's joining in; and this being established and settled, the whole matter comes back to this, that neither Sol, nor Luna, nor Aether, Tellus, and the rest, are gods.
For they are parts of the world, not the proper names of deities; and thus it is brought about that, by your disturbing and confusing all divine things, the world is set up as the sole god in the universe, while all the rest are cast aside, and that as having been set up vainly, uselessly, and without any reality.
Source: Against the Heathen (New Advent)