In Book II of the Republic, Glaucon and Adeimantus strengthen and defend Thrasymachus’s earlier claim that justice is merely an instrumental, and not an intrinsic, good.  Though Thrasymachus has conceded to Socrates, Glaucon observes that he has perhaps done so too hastily, being charmed by Socrates “as if he were a snake.” (358b). Socrates case …