Justice is a central theme in Plato’s moral and political philosophy, and bears on many question posed in his early dialogues. In the Republic, justice, as a political term, is identified with the harmonic balance between the three classes of the city; and, as an ethical term, with the balance between the three parts of the human soul.

Justice before Plato

In the archaic and the classical periods, the Greek sense of justice corresponds to the justice of retaliation. A just act consists in taking an eye for an eye for an evil suffered; in other words, justice consists in inflicting an equal retaliation. In this context, the role of one’s friends and foes is distinctively different. To harm your enemy is equally valuable as to help your friend.

A surviving tenet by Anaximander promotes the retaliation to a principle of cosmic order: “The source from which existing things derive their existence is also that to which they return at their destruction, according to necessity; for they give justice and make reparation to one another for their injustice, according to the arrangement of Time” (frag. 1).

The text takes us in front of a cosmic court, where justice is administered on some “existing things” for the injustice they committed against others. The familiar image of a civil court is illuminating us about the remote and ungraspable secret of the order of the world. In employing the metaphor of the court, Anaximander implies that this obvious strife is ultimately tantamount to justice, for no power resolutely prevails over its opposite, and thus balance always triumphs. Therefore, the coherence and the order of the World is maintained.

The echo of Anaximander’s perception of the cosmic justice is found in the Heraclitean “justice [is] strife” (“One must realize that war is common, and justice strife, and that all things come to be through strife and are †ordained†”, frag. 80). War and strife are at one with justice, for only through them the unity of the opposites is achieved – that is, the hidden harmony of the world. The philosophers become adept in the archaic perception of justice as the act of taking revenge for an injustice, and they advance it to a principle of universal harmony and order.


In keeping with Vlastos, we should attribute the first explicit rejection of justice as retaliation to Socrates. Vlastos comes out to show that even though the principle of retaliation is often impugned in the extant literature, it remains dominant until the times of Socrates – and even after that, for even Aristotle accounts for it, although he does not endorse it. The principle is concisely described in Plato’s Meno: “First, if you want the virtue of a man, it is easy to say that a man’s virtue consists of being able to manage public affairs and in so doing to benefit his friends and harm his enemies and to be careful that no harm comes to himself” (71e).

However, Socrates of the early dialogues denies the compensation of one act of injustice with another unjust act. He insists that one thing he knows for sure is that “one should never do wrong in return, nor do any man harm, no matter what he may have done to you” (Crito 49c-d). And Socrates will put in practice this rule by sacrificing his life – for he deemed that his escape from prison would amount to a retaliation of the wrong that was done to him by the city and the laws of Athens. But to do wrong is worse than to suffer it, because the former inflicts harm into the doer’s soul. The new Socratic ethical thesis amounts to the dismissal of the retaliation principle – a thesis that can be attributed to the historical Socrates, if we take into account the way he upholds it in the platonic texts.

Platonic justice  

Plato will abide to the Socratic thesis by ruling out the principle of retaliation. His own view on justice will be established on the integrity of the agent’s soul. In the Gorgias, which is typically dedicated to rhetoric, but essentially discusses justice, Plato claims that justice makes a man happy. He is essentially endorsing the Socratic approach by upholding two propositions: that it is better to suffer injustice than to commit an unjust act; and that it is better for one, who has done wrong, to be punished than to avoid punishment. Although, these arguments are not sufficiently supported, they provide Plato the opportunity to severely attack what he considers to be the common sense of justice of the democratic Athens of Pericles. The young and ambitious Calicles defends the natural law (against conventional law), according to which a few superior people outclass the others, and have the right to satisfy their desires, and take the lion’s share in goods. Thus, justice is identified with the interest of the stronger – as the sophist Thrasymachus advocates in the First Book of the Republic. Socrates will question the importance of satisfying one’s desires as a condition for happiness, and he will try to show that the tyrant ends up unhappy; for all that, he does not convince Calicles.

The question of justice is resolutely met in the Republic, that is, in Plato’s dialogue “on justice”. Platonic justice hinges on the tripartite division of the human soul into three parts: the appetitive, the spirited, and the rational – a division which correspond to the three classes of the platonic city. Justice, firstly as a political notion, is identified with the harmonious balance of the three classes of the platonic city under the rule of the philosophers-kings; secondly, as an ethical notion, justice is identified with the balance between the three parts of the soul under the rule of the rational part. This definition of justice bears on a previous approach in the same work, where it was conceded that “justice is doing one’s own work and not meddling with what isn’t one’s own” (433a). If each class of the city, and each part of the soul is preoccupied with its own occupations without taking up those of the others, then a certain balance is configured, which is called just. To be sure, this definition of justice can play out only on the condition that the ruler’s own occupation in the city, and the rational part’s own occupation in the soul, is not only true knowledge, and expansion of wisdom, but the guiding of the other classes and parts respectively. Thus, the functionality of justice is predicated on a sort of multitasking allowed only to the philosopher-kings and the rational part of the soul.

That the attainment of justice clings primarily on the efficacy of the rulers and of the rational part of the soul is indicated by the fact that Plato dedicates the central books of the Republic not on justice, which is the subject of his inquiry, but on the good. The novel Idea of the good is demonstrated as the basis of reality and knowledge; additionally, the multi-annual education of the guardians aims exactly at their awareness of the good. Consequently, wisdom, which is the virtue of the dominant part of the city and the soul, lies at the basis of Plato’s concept of justice. Once more, the platonic thesis that virtue is knowledge is confirmed.

Author: Vassilis Kalfas
  • Cooper, J. M. Reason and Emotion. Princeton, 1999.
  • Cooper, J. ed. Plato: Complete Works. Indianapolis, 1997.
  • Freeman, K. Ancilla to the Pre-Socratic Philosophers. USA, 1941.
  • Irwin, T, Plato’s Ethics. New York, Oxford, 1995.
  • Vlastos, G. Socrates. Ironist and Moral Philosopher. Cambridge, 1991.
  • Robinson, T.M. Heraclitus:Fragments : a text and translation. Toronto, 1987.
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