What Is a Person with a Soul in Harmony Called in Plato's Republic?

In Plato’s Republic, a person whose soul is in harmony is called a just person (in Greek, dikaios). Justice, for Plato, is not mainly about obeying laws or treating others fairly. It is an inner condition in which the three parts of the soul, reason, spirit and appetite, each do their own work, with reason ruling. Plato states this in Book IV (441d-444a). Plato also describes temperance (sophrosyne), the agreement of the parts about which should rule, as a kind of harmony (430e, 432a), so harmony language attaches to both virtues, though he treats them as distinct.

What are the three parts of the soul?

Plato divides the soul by arguing that one thing cannot be opposed to itself in the same respect, so when we feel pulled in two directions, different parts must be involved (435b-441c). He identifies three:

• Reason (logistikon), the part that thinks, calculates and loves truth. It is fitted to rule because it can see what is good for the whole soul. See the rational soul.
• Spirit (thumoeides), the part linked with anger, shame, ambition and the love of honour. At its best it acts as reason’s ally. See the spirited soul.
• Appetite (epithumetikon), the part of hunger, thirst, sexual desire and the love of money. Left alone it is insatiable. See the appetitive soul.

For the full treatment, see the tripartite soul.

How does Plato say the harmonious person is just?

Plato approaches the question through an analogy. In Book II Socrates proposes to look for justice in the city first, because it is larger and easier to read, and then to look for the same thing in the individual (368c-369a). The city’s three classes correspond to the three parts of the soul: the rulers (guardians) to reason, the warrior auxiliaries to spirit, and the producers to appetite. A city is just when each class does its own work and does not meddle with the others.

The parallel in the individual is stated at 441d-444a. The just person, Socrates says, does not let any part of the soul do the work of another. He puts his own house in order, rules himself, and becomes his own friend. He brings the three parts into tune, comparing them to the lowest, highest and middle notes of a musical scale, and so turns from many into one (443d-e). Only then does he act, whether in business, politics or private life, and he counts as just any action that preserves this order.

The words are Socrates’ own in the dialogue, and the claim that justice is the health of the soul is Plato’s argument, not a settled fact. It answers the challenge Glaucon and Adeimantus pose in Book II: to show that justice is worth having for its own sake and not just for its rewards. See what makes a good life for Plato.

What is the person whose soul is out of order?

Plato calls the opposite state injustice, a kind of civil strife (stasis) in the soul, where one part rebels against the others and seizes a rule it has no claim to (444a-e). He compares justice to health and injustice to disease of the body. The tyrannical person in Books VIII-IX, ruled by his appetites, is his picture of the worst case.

How does this connect to courage and the other virtues?

Plato maps the cardinal virtues onto the same structure. Wisdom belongs to reason, courage to spirit (the preservation of right belief about what is to be feared), and temperance to the agreement of all three about who should rule (430e-432a for the city, 442c-d for the soul). Justice is then the condition in which every part does its own work, and so in which the other virtues are present. See the cardinal virtues and courage in Plato.

Quick answer

• A person with a harmonious soul is the just person (dikaios) in the Republic; temperance (sophrosyne), the parts’ agreement about who rules, is also described as a harmony but is a separate virtue.
• The three parts are reason, spirit and appetite, with reason in charge (441d-444a).
• The picture of harmony is a musical one: the parts are like the notes of a scale (443d-e).
• This is Plato’s account in the Republic, not a term he uses across every dialogue.