Justice and Good in The Republic by Plato.

In The Republic, Plato strives to display through the character and conversations of Socrates that justice is better than just the proper good for which men must strive for, regardless of whether they could receive equal benefit from choosing otherwise. His method is to use the dialogue from Socrates, questions which led the reader from one point to another, supposedly with convincing logic by obtaining agreement to each point before proceeding to the next, and so constructing an intriguing argument.

In the beginning, his two listeners ask the question of whether justice is stronger than injustice, the consequences of the two, and what makes the first right and the second wrong. As a response, Socrates deals directly with the concept of the individual's inner goodness and decency, but also ties it to his idea of the perfect state, which is a republic of three classes of people with a developed social structure and little in the way of recreation.

Although Socrates returns regularly to the concept of justice in his statements on the perfect city-state, much of it seems off topic. One of his main points, however, is that goodness is doing what is best for the greater good, rather than for individual happiness. There is a real sense in which his ideals turn on the concepts of virtue, and his belief that ultimately virtue is its own reward.

His first major point is that justice is an excellence of character. He then seeks agreement that no excellence is achieved through destructive means. The function of justice is to improve human nature, which is inherently constructive. Therefore, at a minimum, justice is a form of goodness that cannot be involved in injuring someone's character. Justice, in short, is a virtue, a human excellence.

His next point is that acting in peace with excellence brings happiness. Then he ties excellence to one's function. His examples are those of the senses -- each sensory organ is excellent if it performs its function, as the eye sees, the ear hears. Therefore, the just person is a happy person is a person who performs his function. Since these are tied together, injustice can never exceed these virtues and so justice is stronger and is the good.

However, Socrates does not stop there. He goes on to examine the question of the nature of justice and the just life. He identifies the three of the Athenian virtues: wisdom, courage, self discipline.