He believes that fear of punishment for injustice is all that maintains our praise of justice. Gyges was willing to discard all sense of justice and nobility once the opportunity to act freely presented itself. 5. Socrates' use of the city as metaphor in his discussion of justice is the long way of describing the usefulness of justice and its application in human life. His description of a good city is based on the assumption that such a city would be, by matter of definition, just as a virtue. By showing that justice could exist to make a city better, if only in a highly idealized form, Socrates suggests that such a possibility is also available to individuals. His metaphor outlines how justice can be an integral part of civic and individual organization.

Socrates' city has been initially formed to promote the well being of all of its citizenry. This is, after all, an idealized city meant to prove a point. The principle organization of the city is a division of classes between philosopher kings, guardians, and a class of producers. In other words, Socrates divides his city among rulers, soldiers, and workers. Since the tendency of power over others is to corrupt, Socrates proposes that philosophers rule the city. These unique kings would be least likely to succumb to the corrupting temptation of power. In application to the just soul, then, we can see that Socrates' city has lessons. As in the city, the just soul can be built on the premise that action can be taken that does not harm others and that avoids corruption.

7. Education, according to Socrates, in the ideal city must help perform an important function. One of his main concerns in the city was that the tendency of power to corrupt be curbed at all costs. Otherwise, those who were put in charge of protecting the city could easily fall victim to the desire to control and dictate life to all other citizens, thus destroying the ideal justice of the city.

Education in music was designed to improve the soul of the students, while education...

It was Socrates' contention that man could be improved upon through the direct application of education. Through music and gymnastics, Socrates proposed to improve upon the character of those given power in the city so as to prevent them from upsetting justice. Their education in music and gymnastics would promote certain values of moral action and justice that would help maintain the ideal balance Socrates proposes. In terms of the city-soul metaphor, this tenet implies that a well-rounded education that improves upon the body, mind, and soul of the individual can be employed to cultivate a sense of justice.
9. By the end of Book IV of the Republic, Socrates has come to the conclusion that good practices will lead to virtue and bad practices to vice. Within the context of the city, this means that justice occurs in the city when its processes and organization are in line with the natural order of the world. Socrates describes three parts to the ideal city, three classes of organization: rulers, auxiliaries, and producers. He also describes three divisions of the human soul, psychological attitudes in three classes: rational, spirited, and appetitive. In these three things, Socrates argues that the first love wisdom and truth (the philosophers/rational individual), the second victory and honor (the guardians/spirited individual), and the latter love profit and money (the producers/appetitive individual).

A person will be just in the sense that all three of these parts of the soul are functioning as they should: one is rational and understands what is good for him and what is not, one is spirited and adheres to a conception of courage in spite of possible pains/pleasures, and one is appetitive to the benefit of productivity and profit. After all, no individual is wholly rational or wholly spirited, but instead a complicated combination of all three of these parts. Justice brings these three virtues into perfect functioning with one another in the human soul just as it must in the ideal city for it to function correctly. The just person is moderate, wise, and courageous, whereas the unjust person/city fails at one or all of these virtues.