Justice: Plato vs. Aristotle

Plato and Aristotle, arguably the most important philosophers of their time, both made attempts to define justice. Being that Aristotle was a student of Plato, their ideas share many similarities. Both viewed justice as the harmonious interaction of people in a society. However, Plato defined his ideal of justice with more usage of metaphysics, invoking his Form of the Good, while Aristotle took a more practical approach, speaking in terms of money and balance. Although Aristotle's ideal of justice may seem superior, upon further inspection, Plato's ideal of justice is the stronger.
Plato defines justice in terms of two types, group and individual. Group justice is a type of political justice and Plato identifies political justice as harmony in a structured political body. Plato's ideal society consists of three classifications of people: producers, auxiliaries and guardians. Producers are people such as farmers and craftsmen. Auxiliaries are the warrior class whose job is to protect the city and carry out the orders of the guardians. The guardians are the ruling class, raised from an early age to be virtuous. Plato's ideal of political justice relies on the principle of specialization. Each person in the society must fulfill the role that he is best suited for, his arête, and not the role that he may desire to fill. According to Plato, individual justice mirrors political justice. He discusses the tri-partite soul in his Republic. The tri-partite soul consists of three parts: the rational, the spirited and the appetitive. The rational part of the soul searches after the truth. The spirited part desires honor and is responsible for our feelings of anger and indignation. The appetitive part is lust, especially for money. Justice in the individual is analogous to justice in the society. An individual is just when the three parts of his soul are fulfilling their intended roles. The rational part rules the soul, the spirited part supports the rule of the rational