Plato argues that wisdom based on truth and reason is at the heart of the just person and the just society. He divides the general population into three classes that correspond to the three elements of the individual soul - reason, appetite and spirit.
- the statesmen (reason - philosopher)
- the general civilian population that provides for material needs (appetites - pleasure seeker)
- the executive force - army and police (spirit - man of action)
This division is made on the basis of education provided for by the state, not by birth or wealth. Everyone is assigned to an appropriate rank through a process of examination. The state is just if it is ordered in this way, because each of the elements plays its own part and keeps within its boundaries. Such a society is a true aristocracy (rule by the best).
Plato considers aristocracy to be preferable to democracy (where people or the 'mob' rule), plutocracy (where the rich rule) or oligarchy (where a clique rules).