Before arriving at the final definition of Justice, in Book I and II, Plato argues, against the other participants in the discussion, that paying debts and speaking the truth is not enough to define justice (90). Indeed, he defends that justice is more useful than anything else (92.
After agreeing that Justice is wisdom and virtue, and that injustice is a vice and ignorance (121), he continues to explain that the state cannot be exercise unless it is done with justice (122).
He says that justice is a virtue of the soul, and on the contrary, injustice a defect of it (126), and because it is a human virtue, the just man will live well, and the unjust man will not be happy. Analogically, the unjust ruler of the state will be evil (126). For Plato, justice is “one of the greater goods which are desired indeed for their results, but in a far greater degree for their sake” (144).
Justice can be referred to both a person as well as to a State. Because the State is larger than an individual, when exercised with Justice this one is larger and easily discernible than in an individual (146). Furthermore, for Plato, justice is found in the proper relationships between the parts of the whole. It is not found in any part itself. For that reason, for Plate for justice to be exercised in the State, all members of it must fulfil its parts. It is only when each member does its part that can be said that justice is the virtue of the State (151).
At the same time, individual happiness also depends on largely on the relationship with others. For Plato, the whole has more weight than the singular parts.
In Chapters 5 and 7, Plato explains that rulers need to have a knowledge of the form. In these chapters, he talks about the philosophy of the Forms, and he explains that rulers need to know the form of justice to be able to exercise their roles in the state with it.
Works Cited
Leitch, David. Great Questions in Politics. Northridge: Department of Political Science, California State University.
