In Book II of Republic Plato constructs a city from scratch because he claims that it is much easier to find justice in a city, than to try and look for it in a single man (Plato 100, 368d). In this city he places a variety of different craftsmen (Plato 100-103, 369d-371e), which correspond with the appetitive element of the soul, auxiliaries to guard the city, corresponding to the spirited element, and guardians to rule over the city, as the reason rules over the soul (Plato 104, 374e). Plato proposes that each person within his city has a defined role, based upon his or her nature, because a city benefits more “if each person does one thing for which he is naturally suited” (Plato 101, 370c) as opposed to performing many different roles. This is similar to how he defines that each element of a person’s soul has its own task for which it is naturally suited. In defining this Plato asserts that each person is happiest performing his or her naturally defined role and that in doing so they would make the whole city as happy as possible (Plato 130, 420b-c). After Plato finishes defining his city and the roles of each of its three classes he is now free to attempt to find justice within his city. He does this in Book IV by first finding three other virtues, wisdom, courage and temperance, allowing that what is left in the
Cited: Plato. "Republic." Classics of Moral and Political Theory Fourth Edition. Ed. Michael L. Morgan. Indianapolis: Hackett Publishing Company, 1992.