Echecrates presses Phaedo of Elis to give his account of Socrates’ death. Socrates had been condemned to commit suicide by drinking hemlock, and a number of his friends and fellow philosophers had gathered to spend his last hours with him. Phaedo explains that among those present with him were Crito and two Pythagorean philosophers, Simmias and Cebes.
In Phaedo’s account, Socrates explains to his friends that a true philosopher should look forward to death. The purpose of the philosophical life is to free the soul from the needs of the body. Since the moment of death is the final separation of soul and body, a philosopher should see it as the realization of his aim. Unlike the body, the soul is immortal, so it will survive death.
Socrates provides four arguments for believing the soul is immortal.
He bases the first, known as the Argument from Opposites, on the observation that everything comes to be from out of its opposite. For example, a tall man can become tall only if he was short previously. Since life and death are opposites, we can reason analogously that, just as the living become dead, so the dead must become living. Life and death are in a perpetual cycle such that death cannot be a permanent end.
The second argument, known as the Theory of Recollection, asserts that learning is essentially an act of recollecting things we knew before we were born but then forgot. True knowledge, argues Socrates, is knowledge of the eternal and unchanging Forms that underlie perceptible reality. For example, we are able to perceive that two sticks are equal in length but unequal in width only because we have an innate understanding of the Form of Equality. That is, we have an innate understanding of what it means for something to be equal even though no two things we encounter in experience are themselves perfectly equal. Since we can grasp this Form of Equality even though we never encounter it in experience, our grasping of it must be a recollection of immortal knowledge we had and forgot prior to birth. This argument implies that the soul must have existed prior to birth, which in turn implies that the soul’s life extends beyond that of the body’s.
The third argument, known as the Argument from Affinity, distinguishes between those things that are immaterial, invisible, and immortal, and those things that are material, visible, and perishable. The soul belongs to the former category and the body to the latter. The soul, then, is immortal, although this immortality may take very different forms. A soul that is not properly detached from the body will become a ghost that will long to return to the flesh, while the philosopher’s detached soul will dwell free in the heavens.