30 Moreover, when the question is put to them, how it comes that one image is seen of a body from which images emanate in countless multitudes, their answer is, that just because the images are emanating and passing in such multitudes, the effect produced by their being crowded and massed together is, that out of the many one is seen. The absurdity of this Cicero exposes by saying that their deity cannot be thought of as eternal, for this very reason, that he is thought of through images which are in countless multitudes flowing forth and passing away. And when they say that the forms of the gods are rendered eternal by the innumerable hosts of atoms supplying constant reinforcements, so that other corpuscles immediately take the place of those which depart from the divine substance, and by the same succession prevent the nature of the gods from being dissolved, Cicero replies, “On this ground all things would be eternal as well as the gods,” since there is nothing which has not the same boundless store of atoms by which it may repair its perpetual decays. Again, he asks how their god could be otherwise than afraid of coming to destruction, seeing that he is without a moment's intermission beaten and shaken by an unceasing incursion of atoms,— beaten, inasmuch as he is struck by atoms rushing upon him, and shaken, inasmuch as he is penetrated by atoms rushing through him. Nay, more; seeing that from himself there emanate continually images (of which we have said enough), what good ground can he have for persuasion of his own immortality?
31. As to all these ravings of the men who entertain such opinions, it is especially deplorable that the mere statement of them does not suffice to secure their rejection without any one controverting them in discussion; instead of which, the minds of men most gifted with acuteness have accepted the task of copiously refuting opinions which, as soon as they were enunciated, ought to have been rejected with contempt even by the slowest intellects. For even granting that there are atoms, and that these strike and shake each other by clashing together as chance may guide them, is it lawful for us to grant also that atoms thus meeting in fortuitous concourse can so make anything as to fashion its distinctive forms, determine its figure, polish its surface, enliven it with color, or quicken it by imparting to it a spirit?— all which things every one sees to be accomplished in no other way than by the providence of God, if only he loves to see with the mind rather than with the eye alone, and asks this faculty of intelligent perception from the Author of his being. Nay, more; we are not at liberty even to grant the existence of atoms themselves, for, without discussing the subtle theories of the learned as to the divisibility of matter, observe how easily the absurdity of atoms may be proved from their own opinions. For they, as is well known, affirm that there is nothing else in nature but bodies and empty space, and the accidents of these, by which I believe that they mean motion and striking, and the forms which result from these. Let them tell us, then, under which category they reckon the images which they suppose to flow from the more solid bodies, but which, if indeed they are bodies, possess so little solidity that they are not discernible except by their contact with the eyes when we see them, and with the mind when we think of them. For the opinion of these philosophers is, that these images can proceed from the material object and come to the eyes or to the mind, which, nevertheless, they affirm to be material. Now, I ask, do these images flow from atoms themselves? If they do, how can these be atoms from which some bodily particles are in this process separated? If they do not, either something can be the object of thought without such images, which they vehemently deny, or we ask, whence have they acquired a knowledge of atoms, seeing that they can in nowise become objects of thought to us? But I blush to have even thus far refuted these opinions, although they did not blush to hold them. When, however, I consider that they have even dared to defend them, I blush not on their account, but for the race of mankind itself whose ears could tolerate such nonsense.
Source: Letters (New Advent)