The Changes of the Heavenly Bodies, Proof that They are Not Divine. Transition from the Physical to the Mythic Class of Gods
Come now, do you allow that the Divine Being not only has nothing servile in His course, but exists in unimpaired integrity, and ought not to be diminished, or suspended, or destroyed? Well, then, all His blessedness would disappear, if He were ever subject to change. Look, however, at the stellar bodies; they both undergo change, and give clear evidence of the fact. The moon tells us how great has been its loss, as it recovers its full form; its greater losses you are already accustomed to measure in a mirror of water; so that I need not any longer believe in any wise what magians have asserted.
The sun, too, is frequently put to the trial of an eclipse. Explain as best you may the modes of these celestial casualties, it is impossible for God either to become less or to cease to exist. Vain, therefore, are those supports of human learning, which, by their artful method of weaving conjectures, belie both wisdom and truth. Besides, it so happens, indeed, according to your natural way of thinking, that he who has spoken the best is supposed to have spoken most truly, instead of him who has spoken the truth being held to have spoken the best.
Now the man who shall carefully look into things, will surely allow it to be a greater probability that those elements which we have been discussing are under some rule and direction, than that they have a motion of their own, and that being under government they cannot be gods. If, however, one is in error in this matter, it is better to err simply than speculatively, like your physical philosophers. But, at the same time, if you consider the character of the mythic school, (and compare it with the physical,) the error which we have already seen frail men making in the latter is really the more respectable one, since it ascribes a divine nature to those things which it supposes to be superhuman in their sensibility, whether in respect of their position, their power, their magnitude, or their divinity.
For that which you suppose to be higher than man, you believe to be very near to God.
Source: Ad Nationes (New Advent)