Ante-Nicene Fathers, Vol VII:
Lactantius: Chap. VIII.—Of the immortality of the soul

Chap. VIII.—Of the Immortality of the Soul.

The one chief good, therefore, is immortality, for the reception of which we were originally formed and born. To this we direct our course; human nature regards this; to this virtue exalts us. And because we have discovered this good, it remains that we should also speak of immortality p. 205 itself. The arguments of Plato, although they contribute much to the subject, have little strength to prove and fill up the truth, since he had neither summed up and collected into one the plan of the whole of this great mystery, nor had he comprehended the chief good. For although he perceived the truth respecting the immortality of the soul, yet he did not speak respecting it as though it were the chief good. We, therefore, are able to elicit the truth by more certain signs; for we have not collected it by doubtful surmise, 1351 but have known it by divine instruction. Now Plato thus reasoned, that whatever has perception by itself, and always moves, is immortal; for that that which has no beginning of motion is not about to have an end, because it cannot be deserted by itself. But this argument would give eternal existence even to dumb animals, unless he had made a distinction by the addition of wisdom. He added, therefore, that he might escape this common 1352 linking together, that the soul of man could not be otherwise than immortal, since its wonderful skill in invention, its quickness in reflection, and its readiness in perceiving and learning, its memory of the past, and its foresight of the future, and its knowledge of innumerable arts and subjects, which other living creatures do not possess, appear divine and heavenly; because of the soul, which conceives such great things, and contains such great things, no origin can be found on earth, since it has nothing of earthly admixture united with it. But that which is ponderous in man, and liable to dissolution, must be resolved into earth; whereas that which is slight and subtle is incapable of division, and when freed from the abode of the body, as from prison, it flies to the heaven, and to its own nature. This is a brief summary of the tenets of Plato, which are widely and copiously explained in his own writings.  

Pythagoras also was previously of the same sentiments, and his teacher Pherecydes, whom Cicero reported to have been the first who discoursed respecting the immortality of the soul. And although all these excelled in eloquence, nevertheless in this contest at least, those who argued against this opinion had no less authority; Dicæarchus first, then Democritus, and lastly Epicurus: so that the matter itself, respecting which they were contending, was called into doubt. Finally, Tullius also having set forth the opinions of all these respecting immortality and death, declared that he did not know what was the truth. “Which of these opinions is true,” he said, “some God may see.” 1353 And again he says in another place: “Since each of these opinions had most learned defenders, it cannot be divined what is certainty.” But we have no need of divination, since the divinity itself has laid open to us the truth.  

Footnotes

Suspicione.  

Communitatem.  

[“We must wait patiently,” said Socrates, “until some one, either a god or man, teach us our moral and religious duties, and remove the darkness from our eyes.”—Alcibiad , ii., Opera, vol. v. p. 101, Bipont.]