All three are found in the individual but vary in their degree of existence and are specific in each case. Plato evidently patronizes the reason in his three part soul, since it is with reason that one can comprehend the Forms, which themselves are the ultimate in beauty and truth. Accordingly the city, like the individual, has three parts that conform to the parts of the individual soul. The common people make up the appetite, which is the bottommost part. These would be craftsmen, laborers, and farmers who carry out the menial tasks necessary to the functioning of the City. This sect of the community is left to their own inclination, to enjoy and pursue physical and material pleasures, as they are not capable of grasping the Forms. The soldiers are to make up the second tier, which is the spirit. This class of the community has a limited knowledge of the Forms, but not enough to allow rationalization for them to direct their actions. Soldier's fight to defend the State because of their emotional ties to it. In fact, Plato proposes that the government raise children, thereby making the State a common "mother- to all. Finally, reason encompasses the supreme part of the City, and it is from here that philosophers and rulers appear. These are beings that are not drawn into physical pleasures or emotional ties. Rulers and philosophers are engaged with the investigation of the Forms because they can most readily grasp them. This awareness of the utmost good permits for the existence of philosopher-kings and philosopher-queens, who can rule over the spirit and the appetite and ensure that, the City continues to function in its proper working order. .
Plato's view of just government consists of divisions within society, similar to caste systems used in eastern societies today. Everyone is born into a specific part, or class, within the State, and it is in that part that he or she will remain for life.