In the Phaedo, Socrates’ friends gather round him on his last day. He is about to drink hemlock, but they wish to be reassured once again that the soul does indeed live on. They are full of fear that in death the soul meets its end.
What would such a proof look like?
How can one demonstrate the immortality of the soul? Would a story suffice, a logos, or do we require mathematical certainty?ª There is no small danger in confusing that which we know with that which we believe. There is also no small danger in treating matters of faith merely as a subject of hopeful guesswork.
This is why we must distinguish kinds of proof.
From Cause
One kind of proof requires formal knowledge of one’s subject. It begins with first principles or axioms and precedes to demonstrate something as logically necessary. Such proof is possible when we possess comprehensive knowledge of a thing or of its source. This is the mode of mathematical proof.
For instance, I can have knowledge (or proof) that such a seed is an oak and will grow into an oak because I have myself seen the oak tree (the principle or source) and I have seen that seed fall from it.
But recall, we are asking whether the soul is immortal. What would it mean to have knowledge of the soul’s first principle–to have seen such?
All the souls I have met with on this side of life have mortal sources.¹
From Effect
There is a different kind of proof which precedes through effects.
For instance, even when I do not see that such a seed has come from such a tree (or when I do not see comprehensively into the nature of a thing), there is yet another way of coming to know what sort of thing it is and where it is going.
This is the proof of experiment–of a certain kind of life.
I can watch a seedling develop over time and see that it grows more and more into the likeness of some particular plant. I can experience its development and know that it must have such a source or principle guiding and causing it to have such a nature.
This is ultimately the proof which Socrates settles upon in the Phaedo. Though we may not have comprehensive insight into the source of life itself, though we might not begin with the first principle of the human soul, we can yet come to know with greater and greater certainty what the soul is and what it is made for.
As the soul grows in likeness to its Source, we can come to trust that we are indeed made by and intended for God.
A proof of this kind can only be obtained experimentally (though our longing for such proof, for love and for Life Everlasting, may itself contain the seeds of hope, and be itself a kind of answer).
The Corollary
The corollary is twofold:
He who lives in unbelief, who lives as if the soul is most truly earthly, carnal, and without purpose, will come to believe this is the case, for he will become more and more so in himself.
But he who believes and lives according to faith–the faith that we are made by and for life with God–and comes to guide his life according to this principle to the best of his ability, he who makes it his business to live unto the image and likeness in which we are created, shall come to find that he has come to believe more and more deeply in this faith, for such a one comes to grows in longing and in likeness to his true source and end.
Such faith becomes more and more “the substance of things hoped for, the evidence of things not seen” (Heb. 11:1).² Thus our greatest proof is an experimental one which discovers we have come to share in a participatory likeness to our last end.
ª It may be helpful to think of the rhetorical proofs of Aristotle. In some sense the logos of the Phaedo is surrounded by an Ethos.
¹ This is not to deny the possibility of such proof, but our ability to comprehend such a proof is limited!
There is the strictly demonstrative, the analogical, proof by definition, and the likely. The following is ultimately a combination of proof by analogy and definition.
The apex of Socrates logistical argument in the Phaedo develops the idea that the existence of snow depends upon sharing in the form of cold, a form which never changes
Snow is destroyed when heat comes, but the form by which we call snow cold does not itself change.
So too does a living body have life by sharing in life (soul). As snow shares in the form of cold, a living body shares in the form called soul.
A problem remains because the soul is not life itself in the way cold is such. Soul is being defined here as form of body versus a thing in itself and this is still part of the problem.
However, the solution does stand. When a soul is not in a body, it is not destroyed, just as Cold is not destroyed. This is proof by way of definition and analogy, but the manner of eternal life of a soul remains ambiguous without an understanding of a higher form of participation.
The soul, or a rational soul, is not merely life unto a body, but is made for communion with Life itself. For this reason, one may need to follow not only the argument about snow and Cold, but oddness and three. The soul stands not merely as a form unto the body, but in relation to higher forms, just as oddness is not merely the form of three, but stands in relation to number.
Because soul has this twofold nature (life of body and a life directed toward divine communion), we cannot grasp its nature in its entirety with absolute rational comprehension. What the soul is is not entirely contained in itself. We stand on the outside of such an argument unless an experiential proof is found. It is a formally correct proof, but we may require intimacy with or participation in the first principle of the argument.
While we understand soul as form of body (as in the cold to snow analogy), the relation of Soul to its source must remain shrouded in mystery.*
*The argument is furthered by a realization that while cold is chased away by hot, life my leave a body, but is not chased away by the positive form of death. If death is simply the lack of life, life must indeed be somewhere.
² “Hebrews 11:1: Ἕστιν δὲ πίστις ἐλπιζομένων ὑπόστασις πραγμάτων ἔλεγχος οὐ βλεπομένων”, from Blue Letter Bible
Same & Other 