Arguments of the Phaedo
Cyclical Argument (70b-72a)
1. Those that have an opposite come to be from their opposite.
2. Being alive is the opposite of being dead.
So, 3. Living creatures come to be from the dead. (1,2)
4. If X comes to be from Y, then there is a process of becoming from Y to X.
So, 5. There is a process of becoming from being dead to being alive. (3,4)
6. If there is a process of becoming from being dead to being alive, it must be
the process of the dead coming to life.
7. If the dead come to life, then (the souls of) the dead are somewhere.
So, C. (The souls of) the dead are somewhere. (5,6,7)
Argument from Recollection (73c-76d)
1. If X recollects Y at time T, then X knew Y before T.
2. If X senses Y at T and X knows Y at T and X thinks of Z at T and Y is not identical to Z and knowledge of Y is not identical to knowledge of Z, then X recollects Z at T.
3. The Equal is equal and not unequal.
4. Sensible equal things (e.g., equal sticks) are both equal and unequal.
So, 5. The Equal is not identical to any sensible equal thing. (3,4)
6. When we sense (sensible) equal things, we know these equal things and we also know the Equal.
7. When we know something we also think of it.
8. If X is not identical to Y, then knowledge of X is not identical to
knowledge of Y.
9. We sense (sensible) equal things right after birth.
So, 10. We know (sensible) equal things right after birth. (6,9)
So, 11. We think of the Equal right after birth. (6,7,9)
So, 12. Knowledge of any sensible equal thing is not identical to knowledge of the
So, 13. We recollect the Equal right after birth. (2,5,9,10,11,12)
So, 14. We knew the Equal before right after birth. (1,13)
15. We did not know the Equal at birth.
So, 16. We knew the Equal before birth. (14,15)
17. If we knew something before birth, we (i.e., our souls) existed before we
So, 18. Our souls existed before we were born. (16,17)
Affinity Argument (78b-80d)
1. Noncomposite things are indissoluble.
2. Things that always remain the same in the same state are most likely noncomposite.
3. Forms always remain the same in the same state.
4. Sensible things never remain the same in the same state.
5. Forms are invisible.
6. Sensible things are visible.
So, 7. Invisible things always remain the same in the same state, and visible
things never remain the same in the same state. (3,4,5,6)
8. The soul is invisible.
So, 9. The soul is indissoluble. (1,2,7,8)
10. When the soul investigates things that remain the same in the same state, it
too remains the same in the same state.
11. The soul investigates the Forms.
So, 12. The soul is indissoluble. (1,2,3,10,11)
13. The nature of the divine is to rule and lead.
14. The nature of the soul is to rule and lead (the body).
15. If X is F and Y is F, then X resembles Y.
So, 16. The soul resembles the divine. (13,14,15)
17. The divine is indissoluble.
18. If X resembles Y and Y is G, then X is G.
So, 19. The soul is indissoluble. (16,17,18)
The Final Argument (100a-107a)
1. When in us, the F will never admit its opposite (e.g., the Tallness in us will never admit the Short).
So, 2. Things that always bring along the F will never admit its opposite. (1)
3. The soul always brings along Life (into a body).
4. Life and Death are opposites (i.e., opposite Forms).
So, 5. The soul will never admit Death. (2,3,4)
6. What never admits Death is deathless (i.e., always brings along the
So, 7. The soul always brings along the Deathless. (5,6)
8. The Deathless is indestructible.
9. What always brings along something indestructible is itself indestructible.
So, C. The soul is indestructible. (7,8,9)