[The author is Assistant Professor of Philosophy at Lafayette College, Easton, Pennsylvania.]

In the Phaedo, Socrates is sanguine in the face of death. He thinks his soul will continue to exist -- indeed, that it will go on to a better place. Cebes is not so sure. He argues that even if the soul is long-lasting, it might not be indestructible. Maybe it gets "worn out" after several embodiments, and eventually perishes.

To refute this objection, Socrates embarks on a long and difficult argument (100b-107a). What follows is my interpretation and evaluation of it.

The argument requires two principles, each of which is hinted at in the text, and each one which depends on the existence of Forms.

One principle concerns the notion of necessary participation:

P1. If x necessarily participates in form F, then it is impossible for x to exist without participating in F.

So, for example, the number 3 necessarily participates in oddness, since it is impossible for 3 to exist without participating in oddness.

The second principle concerns the notion of opposite form:

P2. If form F is the opposite of form G, then it is impossible for x to participate in F and G at the same time.

So, for example, oddness is the opposite of evenness; thus, it's impossible for the number 3 to participate in both oddness and evennness at the same time.

THE ARGUMENT

1. If x necessarily participates in form F, and the opposite of F is form G, then it is impossible for x to participate in G.

2. The soul necessarily participates in the form of LIFE.

3. The opposite of the form of LIFE is the form of DEATH.

4. So, it is impossible for the soul to participate in the form of DEATH.

5. If it is impossible for the soul to participate in the form of DEATH, then the soul cannot die.

6. So, the soul cannot die.

7. If the soul cannot die, then the soul is indestructible.

Therefore, the soul is indestructible (and Cebes is refuted).

EXPLANATION

Premise 1 follows from P1 and P2. To see this, suppose that x necessarily participates in F. Then at no time can x exist without participating in F. Now suppose that G is the opposite of F. Then x cannot participate in both F and G at the same time. Indeed, there will be no time at which x can participate in G, since participating in G would mean not participating in F -- which it is impossible for x to do while remaining x.

Premise 2 amounts to the view that an essential property of the soul is that it is alive. That this is Plato's view is relatively clear from his insistence that whatever the soul occupies is alive.

Premise 3 is simply assumed.

Line 4 is a lemma; it follows from 1, 2 & 3.

Premise 5 seems plausible, given the theory of Forms. For if the soul cannot participate in DEATH, then it cannot have the property of being dead; in which case the soul cannot die.

Line 6 is a lemma; it follows from 4 & 5.

Premise 7 is simply assumed.

The conclusion follows from 6 & 7.

EVALUATION

It might appear that the most vulnerable premise of the argument is 7: If the soul cannot die, then the soul is indestructible. The general principle being assumed here seems to be that if x cannot die, then x is indestructible. But to see that this general principle is false, consider the contrapositive: If x is destructible, then x can die. This is clearly false. Inanimate objects of all sorts -- rocks, shoes, corporations -- can be destroyed, and hence are destructible, but they do not literally die upon destruction.

Someone might reply to this objection as follows: True, non-living things can be destroyed without dying. But no living thing can be destroyed or go out of existence without dying. Now, the soul is alive -- indeed, it's essentially alive, and so cannot die. Hence, it cannot go out of existence.

This reply depends on the "no deathless exit" principle for living things. According to that principle, no living thing can go out of existence without dying. However, this principle is false. Consider Arnold the ameba. He is a living creature. One day Arnold divides in two. On that day, Arnold goes out of existence. (Otherwise there is really only one, big scattered "ameba" named Arnold!) Yet it seems false to say that Arnold dies on that day. After all, there is no Arnold "corpse". At the time of fission, Arnold was perfectly healthy. And no outside force stepped in and removed or destroyed Arnold. Rather, Arnold appears to be an example of a living thing that went out of existence without dying. Likewise for all fission cases -- and, I suspect, all fusion cases. (For further thoughts on the fate of Arnold, see Jay Rosenberg, Thinking Clearly About Death, Hackett Publishing, 1997, and Fred Feldman, Confrontations With the Reaper, Oxford University Press, 1992.)

These cases show that the "no deathless exit" principle is false: it is possible for a living thing to go out of existence without dying. This can happen in the case of fission. And maybe the soul is capable of fission or fusion. If it is, then it too can go out of existence without dying.

This criticism reveals the importance of Plato's attempts to show, earlier in the dialogue, that the soul is like the Forms in being, among other things, indivisible. For if the soul is indivisible, then it cannot commit fission. In which case a defender of Plato's argument might appeal to a modified version of the "no deathless exit" principle: Either a living thing cannot go out of existence without dying, or the living thing is capable of fission. Now, if the soul is indivisible, it is incapable of fission. Hence, it cannot go out of existence without dying. And since it cannot die, it cannot go out of existence. It is indestructible.

It appears, then, that premise 7 is not quite as vulnerable as it first appeared. At any rate, any attack on it will require taking a stand on the relationships between the concepts of life, death, and existence. I, for one, am not prepared to take any firm stand on this.

The real problem with the argument, as I see it, is premise 2. It assumes that there is a soul, that the soul exists. A more carefully worded argument would not make this assumption. Instead, a more carefully worded argument would replace premise 2 with:

2'. If there is a soul, then it necessarily participates in LIFE.

Of course, thus modified, the argument's conclusion will be conditional, viz., IF there is a soul, THEN it is indestructible.

This criticism reveals the importance of Plato's attempt to show, earlier in the dialogue (74a-76d), that the soul exists. This is the argument from "nearly equal sticks", according to which the only way to account for our knowledge of Equality is to suppose that we have souls that existed apart from our bodies and which were, during that time, acquainted with Equality itself.

No one that I know finds the argument from nearly equal sticks at all compelling. Thus, it seems that Plato has not shown that there is a soul to begin with. The most that Plato has shown is that if there is a soul, then it is indestructible.

By my lights, that's still a staggering philosophical achievement.

Owen McLeod
Department of Philosophy
Lafayette College
Easton PA, 18042 

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