Plato: The Theory of Forms and the Ideal State, Summary

Who Plato was

Plato was born in Athens on an uncertain date: around 427-428 BCE, according to the Stanford Encyclopedia of Philosophy and Treccani. He died, in turn, around 347-348 BCE, at about eighty or eighty-one years old, reports the Internet Encyclopedia of Philosophy.

He studied under Socrates, who died in 399 BCE, when Plato was about twenty-eight. After his travels in Italy and Sicily, around age forty, he returned to Athens and founded the Academy, a school outside the city walls, roughly a mile away: the name comes from a sacred grove dedicated to the hero Academus. Treccani dates the founding to 387 BCE.

This was the Athens of ancient Greece and its poleis, fertile ground for this kind of philosophical and political reflection.

Practical example: when someone says a person lives “in a world of ideas,” detached from concrete reality, the phrase actually comes from here: for Plato, Forms are not an imaginary refuge but the only truly stable reality, more reliable than the world that keeps changing in front of us.

The allegory of the cave and the theory of Forms

For Plato, the world we grasp through the senses falls short of full reality, while a more perfect realm exists, populated by entities he calls Forms, or Ideas: goodness, beauty, equality, unity, sameness, and change are among those discussed in his dialogues. According to the Internet Encyclopedia of Philosophy, everything we perceive is merely a copy of that eternal and changeless realm of Forms.

Two sticks are equal not because equality resides in them, but because they “participate” in the character of the Form of Equality.

This same passage, reports the Internet Encyclopedia of Philosophy, is also the subject of the allegory of the cave, told in Book VII of the Republic: someone chained among the shadows inside a cave takes those shadows for the whole of reality, until he steps out into the light and discovers the true world outside; the first state corresponds to someone who stops at sensible appearances, the second to knowledge of the Forms.

Under the doctrine of recollection, the Forms already dwell in our soul before birth: Treccani calls anamnesis this act of remembering that, for Plato, amounts to knowing.

When the freed prisoner goes back into the cave to teach those who stayed behind, Treccani reads into this the philosopher’s political task in the city: the metaphysics of Forms already sets up, in this gesture, the argument about the state that follows in the Republic.

The Republic and the philosopher-king

Scholars place the Republic in the middle period of Plato’s work, roughly between 380 and 360 BCE, and its aim is to define justice and then use it as a model for a just state.

In the ideal city, which the Stanford Encyclopedia of Philosophy calls Kallipolis, Plato distinguishes three classes: rulers and auxiliaries, together called guardians, and a producing class made up of craftspeople and farmers.

Per Treccani, only this last class keeps private property and its own family; warriors and rulers, instead, share goods, and in Plato’s design, also women. It is a direct contrast with property rights and their limits, covered in another Recap.

The Stanford Encyclopedia of Philosophy reports that, in the Republic’s argument, the philosopher has access to the unchanging essence of the Forms beyond mere appearances: that is why Plato designates him as the city’s ideal ruler, the philosopher-king.

This access still stays restricted: the study of dialectic, the Republic’s highest form of knowledge, is reserved for the best among the guardians, and not before age fifty. Compared with the types of government described in civics textbooks, power in Plato’s city rests on philosophical knowledge, rather than birth or elections.

Justice in the soul and in the city

The Republic’s psychology rests on dividing the soul into reason, an impulsive element (spirit), and appetite.

Plato defines individual justice as the condition in which these three parts each do their own job, without encroaching on the other two; the same thing happens in the city among the three social classes. The good the ideal city’s rulers must aim at, reports the Stanford Encyclopedia of Philosophy, is the unity of the city itself.