In the dialogue, Socrates discusses the nature of the afterlife on his last day before being executed by drinking hemlock poison. Socrates has been imprisoned and sentenced to death by Athenian political leaders for not believing in Athenian gods and for corrupting the youth of the city. The dialogue is told from the perspective of one of Socrates' students, Phaedo of Elis. Having been present at Socrates' death bed, Phaedo relates the dialogue from that day to Echecrates, a fellow philosopher. By engaging in dialectic with a group of Socrates' friends, including the Thebans Cebes and Simmias, Socrates explores various arguments for the soul's immortality in order to show that there is an afterlife in which the soul will dwell following death. Phaedo tells the story that following the discussion, he and the others were there to witness the death of Socrates.
One of the main themes in the Phaedo is the idea that the soul is immortal. Socrates offers four arguments for the soul's immortality:
The Cyclical Argument, or Opposites Argument explains that Forms are eternal and unchanging, and as the soul always brings life, then it must not die, and is necessarily "imperishable". As the body is mortal and is subject to physical death, the soul must be its indestructible opposite. Plato then suggests the analogy of fire and cold. If the form of cold is imperishable, and fire, its opposite, was within close proximity, it would have to withdraw intact as does the soul during death. This could be likened to the idea of the opposite charges of magnets.
The Theory of Recollection