Unlike the Greek philosophers, who traditionally defined justice as a range of behavioral patterns, Plato described justice as a structural entity that consists of individual and political justice. For him, individual justice is to be found in the structure of the human soul, whereas political justice manifests itself in the structure of the city. The latter is just, if every person does what he/she is good at and does not interfere in other people’s business: “Each person must tend to the business that accords with his nature” (Book 5, pg. 117, line 453b). According to Plato, only this condition can contribute to the perfect pursuance of one’s duties.
A just society is the one which consists of the three dependently functioning classes: warriors, rulers, and producers (doctors, craftsmen, farmers, etc.). The conventional role of the rulers is to establish objectives and laws for the development of society; warriors do what rulers tell them to; producers are supposed to obey the rulers and warriors. This hierarchical city structure is just since every class has its own role and does not interfere in life of another one.
As far as individual justice is concerned, it is defined by the tripartite structure of the soul. As well as the city, the human soul has three parts: the appetitive (which longs for carnal pleasures and money); the rational (aspires to knowledge and truth); the spiritual part desires honor. Plato states that, in a just sole, the rational part rules, the appetitive obeys, and the spiritual enhances the rational credo of the rational part. As Plato says, “Justice is establishing the parts of the soul so that they dominate and are dominated by each other according to nature, injustice so that they rule and are ruled contrary to nature” (Book 4, pg. 112, line 444d). The rational part aiming at truth and knowledge dominates in the just soul; honor may be considered only in the light of striving for truth. The most just individual, according to Plato, is the philosopher – “truth lover,” who understands what justice is and knows how to achieve it; consequently, only he is worthy to rule over the just city. However, “the unjust man enjoys life better than the just” (Book 2, pg. 35, line 362c).
No matter how good justice may be, Plato argues that it “is practiced only under compulsion, as someone else’s good - not our own” (Book 2, pg. 33, line 360c). Then why should man be just? Following the philosopher, just deeds are inherently good; that is why a person ought to do just things even if they do not bring instant benefit. In Book IX, Plato uses the three arguments to show that justice is rewarding. Firstly, he sketches the tyrant’s psychological portrait and uses it to demonstrate that injustice influences man’s soul and psyche so negatively that it is not worth them (a just soul is calm and has no troubles). Secondly, he asserts that there are the three major types of character: truth-loving, money-loving, and honor-loving, which all have their own understanding of pleasure and good, just life; but only the philosopher may judge because only he can experience all these types of pleasure. Thirdly, Plato emphasizes that the only possible pleasure is philosophical one, whereas other pleasure types only dull the inward pain.
Presumably, the philosopher did not view pleasure as a reason for justice’s worthiness. Plato tried to show that justice is good by itself, regardless of the benefits it may bring. This is why he does not argue that justice is worthy because it gives pleasure; it is worthy because it has some objective innate goodness. Due to this fact, many thinkers, including Aristotle and modern scholar Richard Kraut, consider that, for Plato, justice is rewarding only in its connection to the Forms, which he perceives as the best things in the world. From this standpoint, justice is worthy as it grasps and imitates the Form of the Good. Imitating the Forms, the just person makes his/her soul as harmonious as the Forms are. Moreover, Plato believes that justice is vague and has to do with something inner: “Justice, although it resembles a mirage, is really concerned with internal rather than external activity - with the true self and its business” (Book 4, pg. 111, line 443c). Consequently, if a person is just, he/she should check his/her true (just) essence and deeds; having done this, man can engage in external business.
On balance, in his work, Plato is trying to solve the problem of political and individual justice. I believe that his solution is successful for the number of reasons. To begin with, I completely agree with Plato’s conception of the just city: the role of every class is distinguished, and each class performs its role; at the same time, all the three classes are interdependent, which presupposes a definite pattern of coordinated interaction. Thus, everything is in order, and it is the order that guarantees successful activity. The same can be said about personal involvement into one’s business: if a person deals only with what he/she is good at, he/she becomes more skilful and can perform his/her role even more beneficially.
Furthermore, Plato’s tripartite structure of the soul also seems reasonable to me. Undoubtedly, the just soul should strive for knowledge and truth, which are the prerequisites for justice. Love for truth is sacred, and a just person has it in the soul. What is more, I also believe that justice is hard to be found as it is the matter of one’s inner perfection and ability to perceive one’s self-image and activity critically.