Plato’s Republic suggests that everyone is better off being just than unjust, yet scholars have disputed whether Plato actually proves it. It is especially unclear whether the Republic shows that non-philosophers are better off being just. I argue that, despite appearances to the contrary, Plato knowingly offers no convincing proof of this, though it is reasonable to infer from the text that Plato genuinely believes it. Thus, the Republic comes to light as a complex piece of protreptic rhetoric: offering an exhortation (‘Be just!’) while withholding the rational basis for that exhortation – thus provoking philosophic inquiry rather than concluding it.
Brown‘Gap’ pp. 277-83extensively reviews the major strategies that have been followed to show that the psychologically just person will necessarily be commonly just. Brown also persuasively establishes that these various strategies are all inconsistent with the text of the Republic. See also Singpurwalla ‘Plato’s Defense’ pp. 269-75.
Vlastos‘Justice and Happiness’ p. 93n.71 implies this. Kamtekar (‘Imperfect Virtue’ p. 333) and Brown (‘Gap’ pp. 284-8) also adopt this interpretation. In this essay I will refer to this position as the ‘narrow interpretation’ of the Republic since it holds that Socrates vindicates common justice only in ideal circumstances. On the other hand I will call ‘the broad interpretation’ of the Republic that which maintains that Socrates defends common justice also in non-ideal circumstances.