Book I of The Republic appears to be a Socratic dialogue on the nature of justice (Gk. dikaiwsunh [dikaiôsunê]). As always, the goal of the discussion is to discover the genuine nature of the subject at hand, but the process involves the proposal, criticism, and rejection of several inadequate attempts at defining what justice really is.
The elderly, wealthy Cephalus suggests that justice involves nothing more than telling the truth and repaying one's debts. But Socrates points out that in certain (admittedly unusual) circumstances, following these simple rules without exception could produce disastrous results. (Republic 331c) Returning a borrowed weapon to an insane friend, for example, would be an instance of following the rule but would not seem to be an instance of just action. The presentation of a counter-example of this sort tends to show that the proposed definition of justice is incorrect, since its application does not correspond with our ordinary notion of justice.
In an effort to avoid such difficulties, Polemarchus offers a refinement of the definition by proposing that justice means "giving to each what is owed." The new definition codifies formally our deeply-entrenched practice of seeking always to help our friends and harm our enemies. This evades the earlier counter-example, since the just act of refusing to return the borrowed weapon would clearly benefit one's friend. But Socrates points out that harsh treatment of our enemies is only likely to render them even more unjust than they already are. (Republic 335d) Since, as we saw in the Phaedo, opposites invariably exclude each other, the production of injustice could never be an element within the character of true justice; so this definition, too, must be mistaken.
The elderly, wealthy Cephalus suggests that justice involves nothing more than telling the truth and repaying one's debts. But Socrates points out that in certain (admittedly unusual) circumstances, following these simple rules without exception could produce disastrous results. (Republic 331c) Returning a borrowed weapon to an insane friend, for example, would be an instance of following the rule but would not seem to be an instance of just action. The presentation of a counter-example of this sort tends to show that the proposed definition of justice is incorrect, since its application does not correspond with our ordinary notion of justice.
In an effort to avoid such difficulties, Polemarchus offers a refinement of the definition by proposing that justice means "giving to each what is owed." The new definition codifies formally our deeply-entrenched practice of seeking always to help our friends and harm our enemies. This evades the earlier counter-example, since the just act of refusing to return the borrowed weapon would clearly benefit one's friend. But Socrates points out that harsh treatment of our enemies is only likely to render them even more unjust than they already are. (Republic 335d) Since, as we saw in the Phaedo, opposites invariably exclude each other, the production of injustice could never be an element within the character of true justice; so this definition, too, must be mistaken.