Just Prospering? Plato and the Sophistic Debate about Justice

This book argues that Plato’s Republic must be understood as developing out of a 5th Century sophistic debate. In Part One the author presents a new analysis of the sophists and their extant texts addressing the important topics of justice and its value. This part shows that already in the 5th Century there was a robust debate about whether the just or unjust life was better for the self-interested individual, and that multiple sophistic authors made inventive and philosophically sophisticated arguments on both sides of this debate. The Moral Cynics argues that the intelligent individual was better off being unjust, whereas the Friends of Justice defended the idea that the just life was better for human beings. Part Two argues that Plato was very much aware of this debate and that in a number of dialogues—but most importantly in Republic—he engaged with this debate. The immoralist challenge that Glaucon and Adeimantus pose to Socrates early in Republic draws from the arguments of the 5th Century Moral Cynics and moreover identifies problems with the arguments of the 5th Century Friends of Justice. By having Socrates make an argument that overcomes the theoretical weaknesses of the earlier Friends of Justice, Plato is able to pose a new defence of justice that is more effective at responding to the Moral Cynics. The book’s analysis of Republic suggests new readings for certain important passages, such as the division of goods.