Plato ends The Republic with the Myth of Er, to discuss points about the immortality of the soul, free will and determinism, individual responsibility, and the role of virtue in obtaining a happy life.

Er the son of Armenius, had been slain in battle, and when the bodies were collected some ten days later, his body was found to be “unaffected by decay.” Two days later he revives on his funeral-pyre and tells others of his journey in the afterlife.

Er’s soul started off its journey in a meadow with four openings, two that lead into the heavens above and two into the earth below. Judges at that intermediate place, directed souls who were deemed moral towards one of the openings in the sky, and those deemed to be immoral towards one of the openings in the earth.

Well, I said I will tell you a tale; not one of the tales which Odysseus tells to the hero Alcinous, yet this too is a tale of a hero, Er the son of Armenius, a Pamphylian by birth. He was slain in battle, and ten days afterwards, when the bodies of the dead were taken up already in a state of corruption, his body was found unaffected by decay, and carried away home to be buried. And on the twelfth day, as he was lying on the funeral pile, he returned to life and told them what he had seen in the other world. He said that when his soul left the body he went on a journey with a great company, and that they came to a mysterious place at which there were two openings in the earth; they were near together, and over against them were two other openings in the heaven above. In the intermediate space there were judges seated, who commanded the just, after they had given judgment on them and had bound their sentences in front of them, to ascend by the heavenly way on the right hand; and in like manner the unjust were bidden by them to descend by the lower way on the left hand; these also bore the symbols of their deeds, but fastened on their backs. — The Republic, Plato

At that time, clean and bright souls floated down from the remaining opening into the heavens, while dusty and worn out souls rose up to that mysterious place from the other opening into the earth. These souls are returning from a long journey and meeting again in this middle place of judgment. Souls that had committed heinous acts and crimes, such as those of tyrants and murderers, were not permitted to rise up, and were condemned to an eternity in the underground.

Plato goes on to describe some of the punishments, especially those of tyrants, in rather vivid detail.

He mentioned that he was present when one of the spirits asked another, ‘Where is Ardiaeus the Great?’ (Now this Ardiaeus lived a thousand years before the time of Er: he had been the tyrant of some city of Pamphylia, and had murdered his aged father and his elder brother, and was said to have committed many other abominable crimes.) The answer of the other spirit was: ‘He comes not hither and will never come. And this,’ said he, ‘was one of the dreadful sights which we ourselves witnessed. We were at the mouth of the cavern, and, having completed all our experiences, were about to reascend, when of a sudden Ardiaeus appeared and several others, most of whom were tyrants; and there were also besides the tyrants private individuals who had been great criminals: they were just, as they fancied, about to return into the upper world, but the mouth, instead of admitting them, gave a roar, whenever any of these incurable sinners or someone who had not been sufficiently punished tried to ascend; and then wild men of fiery aspect, who were standing by and heard the sound, seized and carried them off; and Ardiaeus and others they bound head and foot and hand, and threw them down and flayed them with scourges, and dragged them along the road at the side, carding them on thorns like wool, and declaring to the passers-by what were their crimes, and that they were being taken away to be cast into hell.’ And of all the many terrors which they had endured, he said that there was none like the terror which each of them felt at that moment, lest they should hear the voice; and when there was silence, one by one they ascended with exceeding joy. These, said Er, were the penalties and retributions, and there were blessings as great. — The Republic, Plato

After seven days of dwelling in the place of judgement, the souls traveled for five more days to the Spindle of Necessity, a shaft of intensely bright light that extends into the heavens and that holds together the universe. The souls were then asked to come forth in turn and choose their next life from a scattered plethora of human and animal lives. Lady Necessity, her daughters, and the Sirens were present.

Now when the spirits which were in the meadow had tarried seven days, on the eighth they were obliged to proceed on their journey, and, on the fourth day after, he said that they came to a place where they could see from above a line of light, straight as a column, extending right through the whole heaven and through the earth, in colour resembling the rainbow, only brighter and purer; another day’s journey brought them to the place, and there, in the midst of the light, they saw the ends of the chains of heaven let down from above: for this light is the belt of heaven, and holds together the circle of the universe, like the under-girders of a trireme. From these ends is extended the spindle of Necessity, on which all the revolutions turn. The shaft and hook of this spindle are made of steel, and the whorl is made partly of steel and also partly of other materials. — The Republic, Plato

Plato goes on to describe a system of reincarnation in which the souls choose their own lives and destinies. The presence of a sequence of metaphysical causes is expressed as a cycle of reincarnation. This cycle is eternal and so plays the role of having a broad influence over life. It could be described as a set of constraints.

When Er and the spirits arrived, their duty was to go at once to Lachesis; but first of all there came a prophet who arranged them in order; then he took from the knees of Lachesis lots and samples of lives, and having mounted a high pulpit, spoke as follows: ‘Hear the word of Lachesis, the daughter of Necessity. Mortal souls, behold a new cycle of life and mortality. Your genius will not be allotted to you, but you choose your genius; and let him who draws the first lot have the first choice, and the life which he chooses shall be his destiny. Virtue is free, and as a man honours or dishonours her he will have more or less of her; the responsibility is with the chooser — God is justified.’ When the Interpreter had thus spoken he scattered lots indifferently among them all, and each of them took up the lot which fell near him, all but Er himself (he was not allowed), and each as he took his lot perceived the number which he had obtained. — The Republic, Plato

Not having known the terrors of the underworld, the first soul hastily chose the life of a powerful dictator, only to discover that he was fated, among many other evils, to devour his own children. Although he had been virtuous in his previous life, his virtue had arisen out of habit rather than out of philosophy, and so his judgement was poor. In contrast, the souls that had known the terrors of the underworld often chose a better, more virtuous life, but this they did on no other account than harsh experience.

Each soul was assigned a guardian spirit to help it through its life. They passed under the throne of Lady Necessity, then traveled to the Plane of Oblivion, where the River of Forgetfulness flowed. Each soul was required to drink water; again, Er only watched. As they drank, each soul forgot everything. As they lay down at night to sleep each soul was lifted up into the night in various directions for rebirth, completing their journey. Er then opened his eyes to find himself lying on the funeral pyre early in the morning, able to recall his journey.

Plato then ends with this remarkable paragraph:

And thus, Glaucon, the tale has been saved and has not perished, and will save us if we are obedient to the word spoken; and we shall pass safely over the river of Forgetfulness and our soul will not be defiled. Wherefore my counsel is that we hold fast ever to the heavenly way and follow after justice and virtue always, considering that the soul is immortal and able to endure every sort of good and every sort of evil. Thus shall we live dear to one another and to the gods, both while remaining here and when, like conquerors in the games who go round to gather gifts, we receive our reward. And it shall be well with us both in this life and in the pilgrimage of a thousand years which we have been describing. — The Republic, Plato

In the Mythof Er, when the gods sent the souls to choose their next life, the true nature of the pious and virtuous was revealed.

For Plato, even after death, justice is rewarded and injustice is punished. It is very essential to put an emphasis on the fact that each soul is granted the life it chooses before reincarnation. Plato held and argued the idea that men could choose to be evil or to be good, not holding any doctrine of predestination, meaning, evil men choose to be evil.

Plato’s emphasis on choice regardless of habitation and conditioning clearly that people are responsible for their lives. In other words, men are highly susceptible to conditioning, yet through philosophical rigor, one may take full moral responsibility for the life one leads.