An Analytic Outline of Plato's Phaedo

Brian B. Clayton

1. Argument 1: The Argument from Opposites (70b-72d)

(1) If the souls of the living come only from the dead, then the souls of men who have died must exist in the underworld. [Hypothesis]

(2) By example, all things which come to be and which have an opposite "must necessarily come to be from their opposite and nowhere else."

(3) If opposites come to be from their opposites, then there must be two processes of coming to be.

(4) The process of going from living to being dead is called dying; the process of going from being dead to being alive is called "coming to life again."

So, (5) The souls of the living come only from the dead.

So, (6) The souls of men who have died must exist in the underworld.

Note: This introduces the notions of coming to be (or "change") and opposites.


2. Argument 2: The Argument from Recollection (72e-76e) A. Sub-Argument 1 (72e-73b): Cebes repeats the Meno argument.

B. Sub-Argument 2 (73b-76e): Argument from "Forms"

(1) If learning is recollection, then the soul must preexist its embodiment. [Hypothesis]

(2) We know the Equal.

(3) Seeing two equal things reminds us of the Equal.

(4) Equal things are not the Equal.

(5) Knowledge of the Equal is not based on bodily sensations.

(6) We have bodily sensations from birth.

So, (7) Knowledge of the Equal must precede birth.

So, (8) Learning is recollection.

So, (9) The soul must preexist its embodiment.

Note: This introduces the notion of the Equal, etc. (the Forms). Also note the combination of arguments 1 and 2 at 77c,d.


3. Argument 3: The Argument from Scattering (78b-84b) Hypothesis: If the soul is not likely to be scattered, then it will survive death. A. Sub-Argument 1: The soul is like those things which don't scatter. Note: Soul is in the class of non-composite things. B. Sub-Argument 2: Soul is like the divine and so it is natural for it to be indissoluble. Note: Soul is like that which governs. C. Sub-Argument 3: Even the body, which is naturally dissoluble, survives death. So, it is likely that the soul, which is indissoluble, will survive death (80d) Note: Survival of the body is evidence for the survival of the soul. This is the key argument from which the objections get launched.



1. Simmias' argument--harmony:lyre::soul:body (85e-86d)

(1) The soul is a harmony.

(2) A harmony is invisible, without body and like the divine.

(3) A lyre is physical, bodily, composite, etc. (4) If the lyre's strings are broken, the harmony no longer exists.

(5) If the body is like the lyre and the soul is a harmony (a mixture of bodily elements, then the soul predeceases the body.


2. Cebes' argument--weaver:cloak::soul:body (87a-88b) (1) The soul is like a man wearing a cloak.

(2) The weaver outlasts many cloaks.

(3) The weaver doesn't outlast all cloaks; viz., he doesn't outlast the one being worn at the time of death.

(4) Even if the soul survives the deaths of some bodies, this doesn't mean that it survives the deaths of all bodies.


1. Reply 1: Inconsistent hypotheses (91e-92e)

(1) Learning is recollection and the soul preexists the body. (91e-92a) [Hypothesis]

(2) The soul is a kind of harmony. [Hypothesis]

(3) A harmony is a composite.

(4) A composite can't preexist its components. (92b)

(5) The soul can't preexist its components. (Note: This implies that the soul is a composite, but we had already agreed that the soul is in the class of non-composite things.)

(6) But (premise 1), the soul does preexist its components (i.e., the body).

(7) The soul both preexists and doesn't preexist its components.

(8) Either learning is not recollection or the soul is not a composite harmony. (Note: Since Simmias accepts that learning is recollection, he also accepts that the soul is not a harmony.)

2. Reply 2: An absurd conclusion (92e-94b)

3. Reply 3: Soul _ Harmony (94b-95a)

(1) The soul rules human beings.

(2) The soul rules by opposing the body.

(3) A harmony cannot oppose its elements. (93e)

(4) Soul _ Harmony.

(Note: This reemphasizes the notion that the soul is like that which governs.)


1. Investigate causes of generation and destruction

2. Investigate by means of words (99d-100a)

3. Two hypotheses: (1) If the soul admits death then the soul may perish. (2) If the soul doesn't admit death, then the soul is deathless (and, if the soul is deathless, then the soul is indestructible).

4. An example: The Beautiful as cause (100c,d; 101c)

5. Essential properties and the "nature of Simmias" (102b/c)

6. Opposites (102d-103a): Flee or perish

7. Snow & cold/fire & hot (103c/d); Oddness/Threeness (104a-e)

8. Form-bearers (105b,c)

9. Application to soul/body (105d-e)


1. Aristotle points out that causes answer "why?" questions. He identifies four causes--material, efficient, formal and final. One can see how Aristotle distinguishes these causes by looking at an artifact like a statue, a chair or a desk. How do these causes apply to natural objects like oak trees and human beings?

2. Aristotle also distinguishes between causes as actuality and potentiality. A material cause is potentiality and a formal cause is actuality. How does this apply to natural objects in general and human beings in particular? For human beings, the soul is the form of the body.

3. Are all souls the same? For Aristotle, the answer must be "No," because different souls have different functionalities.

4. In what way does Plato's discussion of causes anticipate but differ from Aristotle's discussion of the four causes?

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Copyright 1998 by David H. Calhoun and Brian B. Clayton.  This page last updated on May 28, 1998.