Justice, separated virtues among the state and the individual, ensured by a society establishes acceptable characteristics, such as wisdom, courage and moderation, among different classes of the state. Plato urges his psychological belief that every individual soul contains three different parts that relate to their social class in the state. In order to obtain a just state, the individuals of the state must adhere to being a just individual. In order to attain a just soul reason must rule, aided by spirit over appetite. .
Plato firstly examines the virtues, characteristics of excellence, through social classes, needed to obtain a just state. The first wisdom, possessed by guardians, enables them to rule the state. Secondly, courage encompasses the warriors who protect the state from enemies, but are friendly to their allies. The third virtue includes the entire state abiding to moderation, self-control, an agreement that the leaders control the state by orders. All rational beings are in need of guidance and education. Guardians through wisdom try to comprehend a purpose, function or end goal, the human telos is rationality. Next, he correlates the social classes of the just state to a similar just individual among the state that maintains three separate parts to the soul. Knowledge is possessed within the guardian class, who seek truth through the first part of the soul: reason. The second, spirit, embraces the warriors who aim for victory and honor. Finally, the artisan class who holds to appetite are money hungry individuals. However, in a just state reason rules, aided by spirit over appetite. .
Plato defines a justice as: "minding one's own business, and not being a busybody." Thus, justice is abiding to a standard suitable for your social class, while not interfering with another social class. For example, guardians control the society, warriors support the rulers, and the artisans produce goods.