The Republic of Plato begins in a similar fashion that many other Platonic dialogues begin, with that of a question. The conversation between Socrates and the aged Cephalus becomes a philosophical discussion of what advantages money has brought to Cephalus' life. Cephalus replies that money has allowed him 'to tell the truth and pay one's debts' (331 b). Nevertheless, Socrates believes this does not portray an accurate description of what justice is. The rest of the first book is a discussion of the definition of justice, mainly that of Thrasymachus' definition. Socrates takes his normal role as an interrogator of peoples' views.
The conversation focuses on justice but actually must be viewed in the context of how each individual can lead the best life possible. Thrasymachus states that 'justice is simply the interest of the stronger' (338 c). In order to support this notion, he states that people who are in power in government make laws, and since these people design these laws, they will serve the interests of themselves. The laws will then be the justice of the subjects, and since the ruling class could be restated as the stronger class, then justice could be stated as being in the interests of the stronger class.
He goes on further to say that the unjust man is stronger than the just man is, and because of that, justice is a vice while injustice is a virtue. Thrasymachus uses the example of private business to show how an unjust man would gain more than a just man would because the just man would pay his taxes fully and would not try to take advantage of others. Therefore, Thrasymachus' viewpoint in Book I of the Republic is that one's life can be better if he is unjust because he will have the ability to take advantage of the just man. In fact, he states "that injustice, when practiced on a large enough scale, is stronger and freer and more successful than justice" (344 c) and is "good policy" (348 d). By the end of Book I, Socrates has Thrasymachus agreeing with his view that "the just man is happy and the unjust man miserable" (353 e), indicating that Thrasymachus has taken back many of his previous statements. This simple statement verifies the fact that Socrates has refuted much of what Thrasymachus argued in Book I; yet, there are a few arguments and statements that makes Socrates' refutation not as strong as it possibly could be.
First of all, a careful examination of Socrates' arguments against Thrasymachus is needed to determine to what extent he refuted Thrasymachus' viewpoint. One of Socrates's stronger points is that "the just man is good and wise after all, and the unjust man is bad and ignorant" (350 c). He convinces Thrasymachus into believing this by asking whether a man of knowledge would follow the standard behavior of other men of knowledge. Thrasymachus grants this to be true, and by using the fact that an unjust man tries to take advantage of all men, Socrates shows that the unjust man is actually ignorant. This is because an ignorant person would "make indiscriminate claims over the intelligent and unintelligent alike" just as an unjust man would do (350 b). Creating a link between ignorance and injustice is quite powerful because of the high esteem in which intelligence was held in these philosophical discussions; the link made between injustice and ignorance can lead to a link being made between intelligence and justice.
Another excellent point that Socrates makes is the fact that unjust men cannot work well together or with anyone else because "injustice invariably plants hatred" (351 d). Socrates uses an example of a large group of unjust individuals and how, eventually, they will not be able to cooperate with themselves because they will have not been acting just towards each other. From this dialogue between Socrates and Thrasymachus, it is stated that not only does "injustices generate hatred, quarrels, and factions" but that "only justice can create unity and love" (351 d). In this light, it can be seen that only through justice can one bring power to a group of people.
There is no manner in which injustice can work together, only through justice can people come together and unite. This greatly weakens injustice because even if a group of unjust people unite for a common goal, eventually it "spawns factions and disunion and then excites enmity among the divided parts" (352 a). Socrates' most powerful rebuttal of Thrasymachus is his defining of the specific function of the soul. Thrasymachus agrees with Socrates' notion that the soul governs how a person lives; this means that a good soul lives a good life, while a bad soul will live life poorly. Using previous arguments from their discussion, Socrates states that the just man will live better than the unjust man because "justice is the peculiar excellence or virtue of the soul" (353 d). All of these arguments of Socrates strongly refute what Thrasymachus' view of the nature of justice and injustice, but it is Socrates' own words that somewhat question the validity of his arguments.
Socrates states "there might be an unjust man who uses force and fraud and gets away without a reckoning" (345 a). This opens a very large area for.