Ambiguity of Plato’s Final Argument in the Phaedo
Bad Moon Rising
Philosophy 211
Professor Jeremy Kirby
November 19th, 2012
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The Phaedo is Plato’s seventh and last dialogue in which he illustrates the
fictional death of Socrates. He does so in a manner to discuss what happens to us after we
die by writing a dialogue between Socrates and other characters right before he dies.
Plato discusses the afterlife, particularly in the sense of our “soul” in four famous
arguments, named: the Cyclical Argument, the Recollection Augment, the Affinity
Argument, and the Final Argument, also known as the Argument from Form of Life. In
this paper I will discuss the Final Argument. In this argument Socrates concludes, “Then,
Cebes, beyond question, the soul is immortal and imperishable, and our souls will truly
exist in another world.” This Argument may be the most convincing of his arguments
about the afterlife, but the way in which he comes to his conclusion that the soul is
immortal and indestructible is flawed, and because of this, I find that Plato’s Final
Argument is not sound and lacking much value. In order to show evidence of this, I will
examine how Plato reached his conclusion.
The best way to examine this would be to pick at the individual premises that
Plato makes. An outline of these premises in Plato’s Final argument and his conclusion
would proceed as follows:
(1) When in us, the Form will never admit its opposite
So,
(2) Things that always bring along a Form will never admit its opposite
(3) The soul always brings along life (into a body)
(4) Life and death are opposites
[2-4] (5) The soul will never admit death
(6) That which does not admit of death is deathless
[5,6]
(7) The soul brings along the Deathless
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(8) The deathless is indestructible
(9) What always brings along something indestructible is itself
indestructible
[7-9]  The soul is indestructible
In order to validate the first three premises, one must first understand Plato’s
Theory of Forms, which he explains in100c – 101e. The Theory of Forms basically
states that there exist real entities such things as Beauty in itself, Goodness in itself, and
Largeness in itself.i He argues that these forms are the reason why things are the way they
are. For example, something is tall because it participates in the Form of being tall, not
because of how many inches it is. One man may be taller than another man by six inches.
The theory of forms would state that this man is taller by virtue of his participating in the
Form of Tallness. An opposing explanation would be that the man is taller “by six
inches.” Socrates argues that his explanation by Theory of Forms is better because it
assigns two different causes for two different phenomena. The taller man is taller by the
Form of Tallness, and the shorter man is shorter by Form of Shortness. The opposing
explanation would say that the shorter man would also be shorter “by 6 inches” just like
the taller man is taller “by 6 inches” giving the same explanation for two opposite
phenomena. Also, more importantly, if the taller man is taller “by 6 inches”, he would be
taller than the shorter man by something which is short. It doesn’t make sense to say that
the tall man is taller than the short man by something short (6 inches).
i
http://www.sparknotes.com/philosophy/phaedo/section10.rhtml
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So according to the Theory of Forms, the Form of Tallness will never admit of
shortness. Socrates agues in premise one that the Form will never admit its opposite,
which is accurate if the Theory of Forms is true. He relates the soul here to other
examples of opposites further validating premise one. One example involves fire and ice.
Snow is always cold, and cannot admit the opposite of cold, heat, without withdrawing or
disappearing completely; fire is always hot, and cannot admit of the opposite of hot, cold,
without withdrawing or disappearing completely.
Plato also makes the argument that when a burning log becomes hot, it possesses
the Form of Heat. But the log could not become hot from something that admits that
opposite of the Form of Heat, such as snow, it had to become Hot because of the fire,
which admits the Form of Heat. This argument supports premise 2 as true. Plato
parallels the idea that a burning log possesses the Form of heat, because it brought upon
by fire, which must only admit the Form of Heat, to the idea that a living body possesses
the Form of Life, because is brought upon by something by the soul, which must only
admit the Form of Life, and never its opposite – Form of Death. At this point, premises
one through five all seem to make sense.
My biggest issue with the soundness of Plato’s final argument however falls
between premises six through eight:
(6) That which does not admit of death is deathless
[5,6]
(7) The soul brings along the Deathless
(8) The deathless is indestructible.
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From 105d6-e9 in the Phaedo, Socrates argues that in being characterized by life, the
soul is essentially ‘not-dead’ or deathlessii:
‘And is there an opposite to life, or is there none?’
‘There is an opposite’
‘What?’
‘Death’
‘Now the soul will never accept the opposite of what she brings along. That
Follows, doesn’t it, from what has been agreed before?’
‘Yes, most certainly it does.’
‘Well now. What name did we give a moment ago to what doesn’t accept the
character of even?’
‘Not-even’
‘And what name do we give what doesn’t accept the just and to what ever wont
accept the musical?’
‘Not-musical and not-just’
‘And the soul won’t accept death?’
‘No, it won’t’
‘The soul is not-dead therefore?’
‘Yes, the soul is not-dead.’
‘Very well. May we say that much has been proved?’ Or how do you feel about
it?’
‘Yes, and proved very adequately, Socrates.’
ii
O’Brien. The Last Argument. Pg. 229
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From being ‘not-dead’ Socrates argues that the soul is ‘deathless’.
I feel there an ambiguity here in what Plato describes as being deathless. In one
sense, he could be describing deathless in the sense that:
(a) deathless means that it is impossible for a soul to exist and be dead.
Or in another sense, he could mean:
(b) deathless means that it is impossible for a soul to be destroyed.
His earlier premises provide evidence of (a), as he states that life is an essential property
of the soul, so we will never have in our hands a soul that exists and is dead, just as we
will never be able to hold fire in our hand that exists and is cold. He has provided enough
evidence to state premises six and seven if describing ‘being deathless’ in sense (a). But
then in premise eight, he describes being deathless in sense (b). He has provided no
evidence for the idea of being deathless in sense (b) so this premise is false.
I would counter here that the soul will never exist with the property of death, as a
fire will never exist with the property of being cold, but as a fire can be put out, or
destroyed, a soul too can be destroyed. Plato wants us to be convinced of sense (b), but
all he is entitled too is sense (a). O’Brien nicely sums up in paper, The Last Argument of
Plato’s Phaedo, I, that because of the ambiguity, “Plato’s argument should have lead to
the conclusion that the soul ‘while it is still soul’ is not-dead, in the sense that fire
‘whenever it exists’ is not-cold. “iii
In the Final Argument, Plato examines Forms and their ability to never admit of
their opposites. At this point, he forms premises that are logical, such as a fire possesses
the Form of Heat, but can never admit of its opposite, cold, unless the fire were to
iii
O’Brien. The Last Argument of Plato’s Phaedo I
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withdraw or perish. Plato then goes on to approximate the nature of souls to the nature of
forms.iv When doing so, an ambiguity arises of what is meant by ‘being deathless’, he
uses the word in two senses: (a) deathless means that it is impossible for the soul to exist
and be dead, and (b) deathless means that it is impossible for the soul to be destroyed. He
provides evidence for sense (a), but then uses sense (b) to derive a conclusion. This
renders the Final argument in The Phaedo unsound and not very valuable.
iv
O’Brien. The Last Argument of Plato’s Phaedo. II. Pg. 105