Should we fear death? Plato's dialogue shows Socrates conversing with his followers immediately before his execution about the philosophical life and the immortality of the soul.
Philosophy as Socrates preaches it is preparation for death: It is a conscious turning away from worldly goods like pleasure, money, and fame in favor of the eternal, and Socrates is confident that after death he'll be living in the midst of that eternal and can barely wait to get going.
Nominally, the dialogue is a proof of the immortality of the soul, and here's the gist: The soul is what makes things alive, right? As the element (whatever it is) that endows life to dead matter, it is, by definition, life itself. So also by definition, it cannot die; it must in fact live on. Plato gives a lot more supporting detail, but yes, the argument is that bad.
The real historic significance here, though, is that in the course of building up to this, Plato gives his first account of the theory of Forms, but strangely, only in passing: Even though this is Plato's first time using the term, Socrates' interlocutors in the story have heard it many times before, and so they're just getting a refresher here. How do we know that the soul just isn't the body itself metabolizing (or whatever the body does that makes it alive) and actually a separate entity that could exist apart from that body? Because in doing geometry, for example, Plato thought we could only perform deductions because we had before-birth knowledge of basic geometric principles. (The Meno that this example comes from was probably the dialogue written just before this one. That dialogue developed this theory of recollection but stopped short of positing Forms.) So mind-body dualism is necessary due to the way our minds work.
According to Plato, when we experience something like a drawing of a triangle, we recognize that it is supposed to be a triangle, but also recognize that it falls short of real triangularity. We recognize that this physical thing (the drawing) is somehow imitating this perfect Form, triangularity. If we didn't have prior knowledge of this form, we wouldn't be able to make sense of our perception at all. Socrates refers to how "we all know" that the world of our perceptions is deceptive (the dialogue doesn't actually take us through skeptical exercises like a stick looking bent in water, but this is what he means), that everything in the phenomenal world is always changing. For a word to actually name something, it has to nail it down, it has to actually be picking out a concept, which is not a changing thing in the world, but is a fixed Idea, and I'm capitalizing the word "Idea" because that's what a Form is: part of an Ideal world, standing above and behind the world of our perception, invisible to us but implicitly referred to by our every cognitive act. Philosophy is an ongoing process of questioning the assumptions of the phenomenal world, turning away from this shifting parade of shadows by seeing how they imply this ultimately more real world of unchanging, Ideal Ideas.
So we've got two types of beings established: the visible ones and the invisible ones. You don't see the soul, do you? Therefore it's one of the invisible ones, part of the Ideal world, which as the party has agreed is eternal. Therefore the soul is eternal. More flawless logic!
Interestingly, Socrates admits that he doesn't really need to set up an unassailable proof here. He just needs to convince himself, so that he can face his death without fear. Near the end of the dialogue, he gives a long cosmological myth about how he thinks the heavens are set up in relation to the earth and what he thinks exactly his soul will do after it leaves his body. There's no way that this level of detail follows from any of the preceding reasoning, so what's going on there?
There's something about myth-making, about philosophical story-telling that is therapeutic. We erect philosophical theories to make sense of the world so as to live well in it. Could it be that Plato told this story not because he literally believed all the words coming out of Socrates' mouth, but to show this process of good story-telling that enlivens us to face a tough world? Despite Socrates' insistence that his death is not a bad thing, the story Plato told with this dialogue is a tragedy of a good man killed unjustly, and all the supporting characters are very sad contra Socrates' wishes.
This ironic interpretation of Plato would perhaps excuse the bad arguments, but there's a danger of circularity: Philosophy is undoubtedly on Plato's account supposed to make us better people, but the only reason we know that is that philosophy tells us so by revealing this general structure of the world by which we mortals are able through philosophy to lift our eyes to the divine. So clearly at least that much needs to be taken in earnest lest Plato's alleged irony corrode the foundation he claimed for philosophy's being an ethically positive force.
Image by Charles Valsechi. Audio editing by Tyler Hislop.