Kant vs. Plato Theory of Justice Essay


Justice, also known as the queen of virtues, is considered to be one of the most powerful and influential virtues that have its basics in the sphere of religion, law, ethics, fairness, and rationality. When we talk about justice, we consider the ideas of something fair and rationale that makes this life fulfilled and interesting. Many aspects of human conditions have been already analyzed by great philosophers and historians, and justice is not an exception. Understanding of justice has deep historic roots, and the brightest works in this sphere were the ones by Immanuel Kant and Plato. These philosophers made successful attempts to not only define the essence of justice but also explain the chosen positions and persuade the reader about their correctness. Even though Plato and Kant’s ideas about justice differ considerably, their disagreements attract the attention of many people and make them evaluate their lives and accept challenges and demands. Justice as a virtue is defined in different ways by Kant and Plato: Plato admits that justice is the concept of specialization that can connect a person to the society this person lives in; and Kant, in his turn, admits that justice should be evaluated as the will of one man to the will of another man according to the existed universal law of freedom; at the same time, their understanding of justice has evident similarities; due to such controversies between two greatest philosophers and thinkers, the modern definition of justice turns out to be rather powerful and inherent to human behavior. This essay compares Plato’s theory of justice to that by Immanuel Kant. It explains the meaning of Plato’s and Kant’s theories of justice and fairness in the context of ideal state.

The Concept of Justice in Philosophy

The idea that justice needs to be accepted as a personal virtue creates certain boundaries for its definition: on the one hand, “it embeds justice in concrete practices and personalities, rather than leaving it in the abstract as just so much ‘theory’”, and on the other hand, “it makes justice into something personal” (Solomon 2001, 90). Taking these two burning facts into consideration, it is possible to believe that justice refers to both human traits and social demands, this is why justice should be regarded somewhere between social and individual applications.

Plato introduced his Republic in far 380 BCE in the form of dialogues between Socrates and other strangers, foreigners, and ordinary people who fought for justice. With the help of this source, people get a good chance to analyze whether a just person can be happier than an unjust person is and to evaluate who has the actual right to define justice and injustice.

At the end of the 1700s, Immanuel Kant offered his vision of justice and introduced his Metaphysical Elements of Ethics, where one of the parts was dedicated to justice elements. There is a certain universal law; people are aware of their rights and duties. They can easily evaluate the situation and take just steps to believe that other people will take the same steps in response. Freedom is an integral part of every human, and if the actions of a person influence the freedom of another person, such actions can be hardly called just, and something needs to be done to improve the situation and respect the rights according to the universal law.

Plato’s Theory of Justice

In a course of a discussion about the concept of justice, Plato was the first to point out the aspect of the just state with all features relevant to it. The idea is that, in ancient times, this idea was innovative due to the vast influence of separated layers of society. The manifestation of justice was supposed with the division of activities and duties among the most significant players in the state. Plato followed in terms of logic while insisting on the solely regulatory value of the government and officials. In this respect, the authoritative performance of higher echelons of state power should not think of themselves as supreme stratum, but as one depending on the rest of the society.

However, Stauffer (2001) admits that Plato’s concept of justice differs a bit from the contemporary understanding of how to achieve a balance of justice in a state. The idea is that the very meaning of justice is vague today due to some social, economical, and political features. As a result, it reflected on the moral side of the society, as it is. However, Plato was annoyed more by the inability of some people in the top positions to lead Athens effectively. He insists in his main work, The Republic, on the significance to strengthen democracy using a rational approach toward functional differences between members of the society. This objective was before he attempted to delineate the right arrangement of people living in some environment.

Plato’s main motives for the just society and the just state lay in the supremacy of reason and soundness of social and political affairs between individuals. He contradicted contemporary opponents, such as Cephalus and Thrasymachus. In return, the last one considered injustice, as the attribute of order and happiness in the state (Bhandari, 2005). Plato was not all abroad after such statements. He continued to insist on the opinion that justice of the society is imposed in its three guts, namely:

  • Guardian-Rulers
  • Guardian-Auxiliaries
  • ‘Money Makers’ (Cotter, 2008, pp. 14)

In fact, in almost all his works Plato underlines the optimal balance in only three constituents. It is referred to his notion of the tripartite nature of the soul that is somehow felt in his understanding of the virtuous republic. Thus, a just man should possess three main qualities of character, i.e. reason, spirit, and appetite (Cotter, 2008, pp. 14). In turn, these qualities can characterize a person following the principles of justice as wise, courageous, and abstinent. An individual or, it is better to say, a person is a vital unit of social, economical, and political affairs. Thus, ascending from the marginal up to the higher layers of the society, each person is aware of a just behavior and particular responsibilities.

Such observation of the main points in Plato’s work gives grounds for constituting optimal delegation of power. Plato works out the concept of justice in practical implementation. He relates a person straightforwardly to state power. It should result in close cooperation described in the formula of cooperation between a man and state power. Such mutual relation between these two constituent parts resolves the dilemma of the struggle between the richest and the poorest parts of society. However, one can fairly admit that those individuals who are destined to provide regulations in society can fight for achieving more amenities. In this respect, Plato sees just the development of relations in the society by prohibiting civil servants to have private property.

One can get to the point about the reasons for the emergence of instability and decline in society. They can come down to greed, corruption, and illegal division of material amenities between representatives of a higher power in the state. Private property is a stimulus for every human being in office to follow the way of injustice. The point is that living in the material world, individuals are not saved from trapping in a pit of greed and injustice. Hence, morality matters in building a just state.

Stauffer (2001) indicates that with all the strong arguments implied in his work, Plato’s understanding of justice needs improvement for the contemporary world. Furthermore, Plato’s work is considered to be a classical evaluation of appropriate standards of justice spread throughout society. Every point of his argumentation leads toward the pathway of the sound mind. On the other hand, justice, as a positive and controversial concept, is hard to determine in reality. Though, there should be people, as Plato admits, who is wise and experienced enough to rule the country. Here come just individuals, the wisest members of society and philosopher kings (Cotter, 2008, pp. 15). Indeed, democracy by Plato can be achieved by the efforts of a group of just people united by universal intentions in building a state.

The attainments of Plato in philosophical thought were highly discussed and analyzed by various philosophers afterward. Among them, Immanuel Kant provided insights patterned with more idealistic reflections on justice. His maxims supported the initial urge of Plato to start increasing justice in the society using constituent units of it. Bhandari (2005) points out that Plato considered justice, as some middle notion between morality and righteousness. This point cannot be underestimated.

Kant’s Theory of Justice

Plato’s and Kant’s ideas about justice differed much, though the fact that certain similarities between them existed also cannot be denied. In general Kant’s understanding of justice was based on something similar to the teaching of Christ: treat people the same way as they treat you. The only difference was the perspective that Kant adopted about this problem. He stated that people should treat each other by the universal law: “Every action is just [right] that in itself or its maxim is such that the freedom of the will of each can coexist together with the freedom of everyone by the universal law” (Kant and Ladd 1999, p. 30). In other words, the action of a person can be considered just if this action does not limit the freedom or do the like harm to any other people. Consequently, if one person hinders the other to perform such a (just) action, then this is regarded as an injustice. At this, Kant perceived justice as an external notion: “Just as justice in general has as its object only what is external in actions, so strict justice, since it contains no ethical elements, requires no determining grounds of the will besides those that are purely external” (Kant and Ladd 1999, p. 32). Quite interesting was Kant’s understanding of coercion. It is not always that coercion is unjust, though, in most cases, it is because coercion limits the person’s freedom. However, when coercion is exercised in the name of justice (for instance, when a debtor demands payment from somebody), then such coercion is right because it takes place by the universal law).

Judging from Kant’s understanding of justice, several differences between his and Plato’s ideas regarding this issue can be marked out. One of such differences is the perspective from which the concept of justice was viewed by these two philosophers. For example, Plato explored the issue of justice with regards to the relations between a person and a society, whereas Kant focused more on interpersonal relations as such. To be more exact, when dwelling on the issue of justice, Plato paid more attention to the justice of a person’s actions and the influence of his/her actions on the integrity of society. In contrast, Kant was more interested in how the actions of one person affected the life and freedom of another person. Thus, Plato viewed justice on a larger scale for he believed that just society was necessary for a perfect state. Kant, in his turn, focused on justice as such and saw it as an aggregate of the conditions under which the wills of two different people can be conjoined; at this, their wills should not violate the universal law of freedom. Another difference is that Kant applies the concept of justice to external and practical relationships of people whose actions can have either a direct or indirect influence on each other (Kant and Ladd 1999). At this, Plato views justice as a human virtue that can create an equitable state or a state where all the individuals behave in a specified way. Therefore, Plato’s understanding of justice presupposes the welfare of the whole (either society or state), while Kant’s view on the concept of justice concerns separate individuals and the conjoining of their wills.

Theory of Justice: Kant vs. Plato

The similarities between Plato’s and Kant’s ideas regarding justice are also worth paying attention to. The first similarity in their ideas is that none of them considered the issue of justice as related to abiding by the laws. Kant attempts to refer the concept of justice to the theory of law stating that “the essence of those laws for which an external legislation is possible is called justice” (Kant and Ladd 1999, p. 28). This, however, does not mean that Kant related the concept of justice to the juridical sphere. His further cogitations on this issue are dedicated to the moral justice and interdependence of the people’s actions on each other. Similarly, Plato considers justice as an individual, rather than a juridical concept. For him, justice is an individual virtue. He does not regard justice as a social notion; he believes that it is an ethical virtue that refers to a person’s internal state and has nothing to do with the social norms that people have to observe. Another similarity is that both philosophers relate the concept of justice to the perfect world. For example, Plato sees justice as a basis for a perfect state where rulers are fair, soldiers are courageous, and citizens are law-abiding. Justice makes people social and improves relations between them allowing them to create a perfect harmonious state. The same goes for Kant’s understanding of justice; he perceives it as something that can improve the relations between the members of the society and make everyone feel free and satisfied. Therefore, it cannot be stated that Plato’s and Kant’s understanding of justice differs much because similarities between their interpretations also exist.

Applying the Theories of Justice to the Modern World

Justice performs an important role in our everyday life, and considering the ideas of Kant and Plato, justice may happen on three different levels. The first level is the evident one that was offered by Kant: people have much in common with one another. This is why just relations should happen between people first of all. The next level is devoted to the relations between a person and a society. A person should treat society just the way he/she wants to be treated by this society. The final level is the relations that happen between nations, and these relations as any other may be both just and unjust. This life is so complicated, and justice still plays an important life. If people behave in a wrong way, they are under a threat of being treated unfairly as well.


Plato’s ideas and Kant’s thoughts about justice and its role in human lives play an important role nowadays. The difference between their approaches is evident indeed; however, this difference fulfills a true meaning of justice and explains its significance to people with different tastes and demands. If Plato focused on relations between a person and society, Kant tried to specify the relations between people. It is impossible to say what kinds of relations are considered to be more serious and more important, this is why when the topic of justice is discussed, it is necessary to evaluate different perspectives and conditions, and the ideas of Kant and Plato properly introduced these conditions. Though justice application may be difficult in some situations, almost every person realizes the ideas of justice and its necessity in society. Justice is closely related to human rights and freedoms; this is why it is wrong and improper to neglect justice.


Bhandari, DR 2005, Plato’s Concept of Justice: An Analysis, Paideia, J.N.V. University, Web.

Cotter, B 2008, Plato: The Just State, Plato Lectures BBV, Part 1.

Kant, I and Ladd, J 1999, Metaphysical elements of justice: Part I of The metaphysics of morals, Hackett Publishing, Indianapolis.

Solomon, RC 2001, ‘Justice as a Virtue’, In James Sterba Social and Political Philosophy: Contemporary Perspectives, Routledge, New York.

Stauffer, D 2001, Plato’s introduction to the question of justice, SUNY Press, New York.

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