In book III, Socrates begins to describe criteria for an ideal city.Socrates begins by describing who should rule this ideal city.
He feels that they must choose guardians who have the state's interest at heart, because they see it identical with their own interest.Socrates feels that the guardians will be the backbone of the state who will protect the state and the people.And, that the guardians will help to provide the education to the people.Once Socrates establishes the idea of providing guardians for the state, Socrates suggests that the rest of the citizens be told a noble falsehood. The noble falsehood that Socrates proposes states that the citizens must be divided into three different classes, gold, silver, and bronze. "They are to be told that their youth was a dream, and the education and training which they received from us, an apprearance only; in reality during all that time they were being formed and fed in the womb of the earth..
." This lie is necessary because Socrates feels that by making different classes the city will become stronger.He tells the people that they are all brothers and that each person has a different role in the city so they will all benefit from each other.If the people did not have certain roles in the state, and were left to find their own happiness, then they would not fulfill their role in the state.This would lead to a weaker and less happy state.
By telling the people this noble lie, Socrates hopes that he can achieve and ideal state. He intends on doing this not through rules and regulations, but by the citizens properly fulfilling their role in the state, and within their social classes.Socrates is also trying to prevent extreme poverty or wealth by telling this lie to the people.In this way, none of the people can dispute their status in society because they were told that they were born into that social class.