10.3 — Plato

He was about twenty-eight when Athens executed his teacher, and everything he wrote afterwards is downstream of that.

He founded the Academy, which ran for nearly nine hundred years. He wrote dialogues rather than treatises, with Socrates usually as the main speaker — which makes it permanently unclear where Socrates ends and Plato begins.

The forms

His central claim, and it grows directly out of Socrates' failure to get definitions (10.2).

Socrates asked what justice is and nobody could say. Plato's answer: they could not say because they were looking in the wrong place.

Consider a circle. Every physical circle is imperfect — drawn with a shaking hand, made of atoms, never exactly circular. And yet you know what a circle is, precisely, and you can prove things about it that are exactly true.

So what are you knowing about? Not any particular circle, because they are all defective. The Circle itself.

**And Plato generalises: for every quality — beauty, justice, equality, goodness, largeness — there is a Form, which is perfect, unchanging, and not located in space or time. Physical things are what they are by participating in the Forms, imperfectly and temporarily.

Which means the world you can see is the world of copies, and the real world is the one you can only reach by thinking.

Parmenides' unchanging reality (10.1), rescued and made to explain the changing one.

The cave

And the image, which is the most famous passage in Western philosophy.

Prisoners are chained in a cave, facing a wall, since childhood. They cannot turn their heads.

Behind them is a fire, and between the fire and the prisoners a walkway along which people carry objects, casting shadows on the wall.

The prisoners see the shadows and hear the echoes, and they name them, and compete at predicting which shadow comes next, and honour whoever is best at it.

That is the whole of reality to them.

Now free one. He turns, and the fire hurts his eyes, and the objects look less real to him than the shadows did. Drag him up the passage into the sunlight and he is blinded and in pain, and he would go back.

Slowly his eyes adjust. He sees shadows, then reflections, then objects, then finally the sun itself — which he understands is the cause of everything he now sees.

And then he goes back down.

His eyes, adjusted to the light, cannot see in the dark. He is worse than the others at the shadow-game. They conclude that going up ruined his sight, that nobody should attempt it, and that anyone who tried to free them should be killed.

Plato wrote that fewer than thirty years after Athens killed Socrates.

Reading the cave

Three levels, and all three are intended.

Metaphysical: the physical world is the shadows and the Forms are the objects.

Educational: learning is painful, disorienting, and initially makes you worse at the game everybody is playing. The freed prisoner is not immediately better off, and this is the honest part.

And political: the person who has seen must return, and will be laughed at, and may be killed.

And notice the detail that does most of the work: the prisoners' competence is real. They are genuinely good at predicting shadows. The problem is not that they are stupid — it is that their entire skill applies to something they have mistaken for reality, and there is no experience available inside the cave that would reveal it.

The tripartite soul

And the psychology, which has held up better than the metaphysics.

Three parts.

Reason — which wants truth.

Spirit — the part that is indignant, competitive, ashamed, and wants honour. Not emotion in general; specifically the honour-seeking, self-respecting part.

Appetite — hunger, thirst, sex, money.

The image is a chariot: a driver with two horses, one noble and one unruly.

And justice in a person is each part doing its own work with reason in charge — not reason destroying the others, which Plato explicitly does not say. Spirit's job is to be reason's ally against runaway appetite.

The observation that makes it convincing: Plato notes a man who wants to look at corpses, is disgusted with himself for wanting to, and looks anyway while cursing his own eyes. A conflict between appetite and the part that is ashamed, observed directly.

And the three parts are recognisable in every subsequent psychology, including Freud's, which is essentially this with different names, and including 5.8's gunas from a different tradition.

The Republic

The just city, constructed as an analogy for the just soul, and it is where Plato is at his most brilliant and his most alarming.

Three classes matching the three parts: rulers (reason), guardians (spirit), producers (appetite).

Rulers are philosophers, selected by aptitude and educated for decades, holding no private property and no families of their own — because Plato judged that property and family are what corrupt rulers.

And his argument for it is the strongest case against democracy ever made, and it deserves to be stated properly.

If you are sick you want a doctor, not a vote. If you are sailing you want a navigator. Governing is a skill like any other, and there is no reason to think a majority of untrained people will choose well. Athens voted for the Sicilian expedition and destroyed itself; Athens voted to kill Socrates.

The reply, which he does not adequately answer: who guards the guardians, how do you identify the wise without already being wise, and what happens when the rulers are wrong and there is no mechanism to remove them. Twentieth-century critics called the Republic the first blueprint for totalitarianism, and the charge is not baseless — it includes censorship of poetry, state control of reproduction, and a founding myth to be told to citizens for their own good.

What is defensible: the diagnosis. Plato is right that democracy has no mechanism for ensuring competence and that voters can be flattered. His solution is worse than the problem, and the problem is real.

What lasted

Four things.

The distinction between appearance and reality, which structures all Western philosophy after him.

The idea that mathematics tells you about something real. Mathematicians are frequently Platonists to this day — they experience themselves as discovering rather than inventing, and Volume II discusses why.

The tripartite soul, which is the ancestor of every model of internal conflict.

And the dialogue form itself. Philosophy as a conversation with objections built in, rather than a treatise.

The criticisms

Aristotle's, made by his own student, is the sharpest and is in 10.4: the Forms explain nothing, because saying a thing is beautiful by participating in Beauty just gives the problem a name.

And the modern one: Plato's real world is inaccessible, unchanging and known by pure thought — which turned out to be exactly the wrong bet. The world of change and observation, which he treated as second-rate, is where every discovery of the last four hundred years has come from.

What to carry from this page

The prisoners are good at the game. Real competence at something that is not what you think it is — that is the actual danger, and there is no experience inside the cave that reveals it.

Learning makes you worse before it makes you better, and it makes you bad at the thing everybody else is scoring.

Reason, spirit and appetite — and spirit's job is to be reason's ally. The part of you that is ashamed of what you want is not the enemy.

And Plato's case against democracy is a real case. The answer to it is not that he was silly; it is that his alternative has no error-correction and democracy does.

Next: 10.4 — his student, who disagreed with almost everything and invented most of the categories everybody still uses.