In The Republic, Plato attempts to demonstrate through the character and discourse of Socrates that justice is better than justice is the good which men must strive for, regardless of whether they could be unjust and still be rewarded. His method is to use dialectic, the asking and answering of questions which led the hearer from one point to another, supposedly with irrefutable logic by obtaining agreement to each point before going on to the next, and so building an argument.
Early on, his two young listeners pose the question of whether justice is stronger than injustice, what each does to a man, and what makes the first good and the second bad. In answering this question, Socrates deals directly with the philosophy of the individual’s goodness and virtue, but also ties it to his concept of the perfect state, which is a republic of three classes of people with a rigid social structure and little in the way of amusement.
Although Socrates returns time and again to the concept of justice in his discourse on the perfect city-state, much of it seems off the original subject. One of his main points, however, is that goodness is doing what is best for the common, greater good rather than for individual happiness. There is a real sense in which his philosophy turns 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 accordance 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 four of the Athenian virtues: wisdom, courage, moderation, and justice. For the bulk of the book, he looks at each virtue separately in terms of the perfect city state, but our focus is on justice. But he makes the point that justice, of the virtues, resides in man’s relations to other men, not just in man as an individual. Thus, it is an excellence in social organization and in the organization of the human soul. So justice is a virtue which must be connected to the function of efficient and healthful cooperation. Justice is in one sense the greatest virtue for it is key to making the other virtues work together for the common good. If all the parts are to work together as a whole, each must have on function to excel at. Like the organs of the body, all contribute to the whole, but the eyes only see, the ears only hear. They do not share functions. Using this analogy, justice would be something like the moral mind which guides the body in its activities. Justice, then is the head, at the top of the hierarchy in social terms. When the other three virtues work together in orderly fashion within the state, justice is produced. But for justice to be produced, it must come from everyone doing his assigned function under the excellent guidance of the ruling class.
Despite his emphasis of justice as a function of the perfect state, Socrates also deals with justice as a personal virtue.He finds that there is a parallel between the organization of the state and the organization of the individual. Just as there are three virtues other than justice, Socrates finds three parts in the individual soul — sensation, emotion, intelligence. The just person, then must have balance between these aspects. Each must function in moderation to contribute to the health of the whole. Appetite and sensation are matters of desire. Desire must be subordinate to reason, or else they will throw the individual out of balance and lead him into injustice and unhappiness. Emotion (spirit and will) also can master desire.
The alliance of emotion and reason is similar, Socrates says, to the rulers and the guardians in the state. Thus, the individual is a miniature state, and justice in the soul is like justice in the state.
In the opposite case, the situation of the unjust, whether state or individual, desires hold a tyranny. Because there is a lack of internal control, outside things move the unjust around at will. Thus the unjust lives a life of fear and anxiety, the fruit of being out of control. Socrates asserts that only the man of reason has pure pleasures. All others have varying degrees of unhappiness. By equating the philosopher with the man of pure reason, he sets up a situation where proof is not so much necessary for any of his points as it is to say that the philosopher, the only one who sees clearly, says so. Interestingly, Socrates couches a form of despotism in terms which are intended to seem benevolent. Since happiness is the sign of justice, and pleasure is one sign of happiness, then the just person is the happy person. Interestingly, he equates true pleasure with knowledge, the province of reason and the philosopher.
Finally, in Book X, Socrates argues for the existence of an immortal soul. With this concession, he makes the point that good is that which preserves and benefits. Justice is good, so it therefore preserves and benefits in this life as well as the next. Therefore, even though a man may wish to behave badly when no one is looking, as with the myth of the ring of Gyges, in fact, behaving justly will have the most rewards.
Ultimately, the difficulty with Socrates’ arguments is that they rely on equating things on to the next in a chain that eventually leads back to the original proposition. But the logic of these connections seems built more on assumptions than on objective truth. This is in keeping with his stance that ultimately what he says is right is right because he is a philosopher, and therefore is by his nature right. The dialectic seems more of a game to get the hearer to go along.