Socrates announces now in the dialogue that he has demonstrated the superiority of the just life as a life to be lived, whether it include external rewards or not. But Socrates sees the universe as being essentially moral, and he argues that experience shows us that the just man will receive his just rewards; the unjust man, his just punishment. The greatest of both will be in the life after the death of the body. Socrates illustrates this situation in the Myth of Er. So we turn now to the story of Er.
Part of Er's fate is that he will tell men yet alive his story of life after death. Er is a brave soldier who dies in battle. Ten days after his death, his body is taken home and laid on the funeral pyre, but there Er comes back to life and tells the story of his adventure.
After Er's soul left his body, it traveled with other souls to a wonderful place where there are two chasms in the earth and two above them in the sky. Between the chasms and between heaven and earth sit judges who pass judgment on the souls of men who come before their court. The just souls were directed to take the right-hand chasm leading into heaven; the unjust souls were condemned to the left-hand chasm down into the earth. Er was told to sit and watch the proceedings of the court, for he was to return to life and tell living men his story. As Er watched, he saw souls coming from the exit-chasms from heaven and earth; those coming from earth were weary and careworn and stained from travel; those from heaven were clean, rested, and bright. The souls told Er their experiences: The just souls had been rewarded for their just lives during their stay in heaven; the unjust, punished in the earth, condemned to wander a thousand years below the ground. The unjust told tales of other more evil men, murderers and tyrants, who were still condemned to suffer longer beneath the earth, never to be released again.
The souls stayed with Er near the chasms for seven days, and then Er and the souls journeyed to where the Fates dwell. The Fates would give the souls new lives as mortals. Each soul was permitted to pick the sort of new life he would lead; some chose wisely while others did not. The first soul chose a new life as a tyrant, thereby condemning himself to a life of misery. Orpheus chose to be a swan; Ajax, a lion; Agamemnon, an eagle. Odysseus, who remembered his earlier sufferings pursuing a life of glory and deeds, chose to be a common citizen.
After choosing their new lives and being granted them by the Fates, the souls were made to drink from the River of Forgetfulness, so that they could remember nothing of the other world and could not tell men of it. Er was forbidden to drink; his fate was that he must remember and tell what he had seen and heard. A great earthquake occurred; the souls were taken away to be reborn to new lives. Er awoke, found himself on his funeral pyre, and told his story.
In thus concluding his argument for the immortal justice meted out to the just and the unjust, Plato is forced to argue the authority of myth because he cannot demonstrate his argument logically; there exists no demonstrable proof. Plato's myth here embraces the doctrine of reincarnation.
Thus it is that, even after death, for Plato justice is rewarded and injustice is punished. We should note carefully that each soul is granted the life he chooses before he is reincarnated. Plato held quite firmly to the idea that men could choose to be evil or to be good, and he did not hold to any doctrine of predestination of a life lived evilly or well. A bad man chooses to be bad.
But how can this be, when we know that a life lived unjustly is a life of misery? Why would a man choose unhappiness? Plato's answer to that is that choices are many times made from ignorance (amathia). The unjust man would realize the woe he is bringing upon himself if only he would listen to his reason and try to learn something. And so we see, truly, that the unexamined life is not worth living.
the Fates in Greek mythology, the Fates (or Moirai) are the daughters either of Night (in some versions) or of Zeus and Themis (in others). They are the spirits who preside over a person's birth, allotting his or her destiny; they are often personified as three women: Clotho, Lachesis, and Atropos, who spin out the thread of life, measure it, and finally cut it off.
Thamyras (or Thamyris) a mythological poet and musician.
Atalanta a mythological huntress, who (in one story) refused to marry any suitor who could not win a footrace against her.