Greek Texts & Translations

"The waning of the moon and again her waxing ^note might be due to the rotation of the moon's body, and equally well to configurations which the air assumes ; further, it may be due to the interposition of certain bodies. In short, it may happen in any of the ways in which the facts within our experience suggest such an appearance to be explicable. But one must not be so much in love with the explanation by a single way as wrongly to reject all the others from ignorance of what can, and what cannot, be within human knowledge, and consequent longing to discover the indiscoverable. Further, the moon may possibly shine by her own light, just as possibly she may derive her light from the sun ; 10.1.95 for in our own experience we see many things which shine by their own light and many also which shine by borrowed light. And none of the celestial phenomena stand in the way, if only we always keep in mind the method of plural explanation and the several consistent assumptions and causes, instead of dwelling on what is inconsistent and giving it a false importance so as always to fall back in one way or another upon the single explanation. The appearance of the face in the moon may equally well arise from interchange of parts, or from interposition of something, or in any other of the ways which might be seen to accord with the facts. 10.1.96 For in all the celestial phenomena such a line of research is not to be abandoned ; for, if you fight against clear evidence, you never can enjoy genuine peace of mind.

"An eclipse of the sun or moon may be due to the extinction of their light, just as within our own experience this is observed to happen ; and again by interposition of something else - whether it be the earth or some other invisible body like it. And thus we must take in conjunction the explanations which agree with one another, and remember that the concurrence of more than one at the same time may not impossibly happen. [He says the same in Book XII. of his "De Natura," and further that the sun is eclipsed when the moon throws her shadow over him, and the moon is eclipsed by the shadow of the earth ; or again, eclipse may be due to the moon's withdrawal, 10.1.97 and this is cited by Diogenes the Epicurean in the first book of his "Epilecta."]

"And further, let the regularity of their orbits be explained in the same way as certain ordinary incidents within our own experience ; the divine nature must not on any account be adduced to explain this, but must be kept free from the task and in perfect bliss. Unless this be done, the whole study of celestial phenomena will be in vain, as indeed it has proved to be with some who did not lay hold of a possible method, but fell into the folly of supposing that these events happen in one single way only and of rejecting all the others which are possible, suffering themselves to be carried into the realm of the unintelligible, and being unable to take a comprehensive view of the facts which must be taken as clues to the rest.

"The variations in the length of nights and days may be due to the swiftness and again to the slowness of the sun's motion in the sky, owing to the variations in the length of spaces traversed and to his accomplishing some distances more swiftly or more slowly, as happens sometimes within our own experience ; and with these facts our explanation of celestial phenomena must agree ; whereas those who adopt only one explanation are in conflict with the facts and are utterly mistaken as to the way in which man can attain knowledge.

"The signs in the sky which betoken the weather may be due to mere coincidence of the seasons, as is the case with signs from animals seen on earth, or they may be caused by changes and alterations in the air. For neither the one explanation nor the other is in conflict with facts, 10.1.99 and it is not easy to see in which cases the effect is due to one cause or to the other.

"Clouds may form and gather either because the air is condensed under the pressure of winds, or because atoms which hold together and are suitable to produce this result become mutually entangled, or because currents collect from the earth and the waters ; and there are several other ways in which it is not impossible for the aggregations of such bodies into clouds to be brought about. And that being so, rain may be produced from them sometimes by their compression, sometimes by their transformation ; 10.1.100 or again may be caused by exhalations of moisture rising ^note from suitable places through the air, while a more violent inundation is due to certain accumulations suitable for such discharge. Thunder may be due to the rolling of wind in the hollow parts of the clouds, as it is sometimes imprisoned in vessels which we use ; or to the roaring of fire in them when blown by a wind, ^note or to the rending and disruption of clouds, or to the friction and splitting up of clouds when they have become as firm as ice.