Introduction to Philosophy, fall 2019

Introduction to Philosophy, fall 2019

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Plato in “The Republic” sets up an argument on why we should be moral and just. To begin with, Plato provides the three parts of an individual’s soul, namely the appetitive part, spirited, and rational part. Individual justice is about keeping these parts of the soul in balance, where reasoning rides over appetite. The other section of the paper explores why it is better to be just than unjust using Plato’s analogy of the just city and the soul. Plato starts his argument of justice by having Socrates suggest the notion of the creation of a perfect magic city. In this paper, I will give Plato’s argument that the soul has three parts, as well as show how the soul should be just rather than unjust.

An argument for Three Parts of the Soul

According to Plato, there are three parts of the soul; rational, appetitive, and spirited. The three parts of a soul constitute the ranking of a just society. A person should keep the three parts of the soul in a balance and ensure that the appetite part submits to reasoning. To begin with, the appetite part of the soul includes an individual’s desires for different pleasures, comforts, and physical satisfactions (Plato 428C [83]). The group considers the desire for things needed to stay alive such as thirst and hunger. In regards to this, Plato claims that a person can be directed by thirst or hunger for something instinctively. Therefore, there is a need for a balance in the three parts of the soul for an individual to be just.

On the other hand, the rational soul is the thinking aspect of all humans that decide what is real and unreal and judges what is true and untrue (Plato 428B [83]). The rational soul is part of an individual that thinks, evaluates, focus ahead, weighs alternative rationally and tends to measure what is best and effective. The spirited soul is part of an individual that gets annoyed when it perceives, for instance, that injustice was done. The spirited soul is where a person loves to encounter and override great problems (Plato 428B [83]). In addition, the spirited soul is a part of an individual that loves success, challenge, and respect.

Why it is better to be just than unjust

The analogy between city and soul is applied to show the value of justice over injustice. According to Plato, all aspects of a soul will get satisfaction if reason rules or controls. Contrary to other parts of the soul, reason understands the legitimate desires of other elements and seeks a balanced plan of life that operates for the benefit of the entire soul. In Plato’s analogy, rulers operating in the just city are ruling based on the interest of everyone and not their own. Plato presents a distinction between the just city and unjust city based on superiority of the balance and harmony. To achieve this, Plato compares an individual whose soul is harmonious to one whose soul is in conflict.

According to Plato, justice results in the happiness of the entire soul, whereas injustice results in sadness. Unlike a just city that results in harmony and peace, the fruits of the injustice are like; oppression of citizens by the rules for their interest. In addition, like a just city, a just soul is balanced and harmonious, while the unjust city is attributed to disharmony and war. Plato says, “if his inward parts do severally their proper work, will, in virtue of that, be a just man, and doer of his proper work” (Plato 441C [93]). The unjust soul is usually possessed by lust, where it sacrifices all other aspects in vain to satisfy their desires. In regards to this, Plato showed that nothing good that comes with being unjust.

Plato transforms injustice to the quality of a person’s soul. It is no longer a personal behavior but an internal status. Plato affirms that the performance of unjust actions will affect the balance and peace of the soul that is important for happiness. Plato uses an individual whose soul is not harmonious. He claims that an individual whose soul is balanced can control and suppress unnecessary desires from influencing their decision. However, Plato defines an individual whose soul is not harmonious as an erotic person with extreme desires and usually unhappy in life.


In the “Republic,” Plato presents a strong argument on why a healthy soul results in happiness. Plato begins the argument by describing the three parts of a person’s soul, namely rational, spirited, and appetitive. Using the analogy of the just city and the soul, Plato argues that an individual whose soul is harmonious pursues justice, which leads to happiness while an individual whose soul is not harmonious seeks injustice, which makes the person unhappy. The injustices that people commit ends up in being unhappy because of the internal conflict. Therefore, real fulfillment and happiness are attained when the soul is just and does the right thing.


Cooper, J. M., & Hutchinson, D. S. (Eds.). (1997). Plato: complete works. Hackett Publishing.