 The focus of the argument has now come to rest where, in Plato’s view, it really belongs: on the psychology of justice, and its effects on the human soul. In fact, these last two arguments amount to a specification of what justice in the soul must be. Justice is a virtue of the soul—in a way, it is the virtue par excellence, since by unifying the soul (as it does the city, or any human group) it enables the other virtues to be exercised in successful action. But of course this does not yet tell us what justice itself is, or how it produces these characteristic effects. And no doubt this is one reason (perhaps among many) that no one ever finds Socrates’ arguments against Thrasymachus very satisfying or convincing: not Glaucon and Adeimantus, who demand from Socrates an argument which will reveal what justice really is and does (366e, 367b, e), not modern readers and interpreters, and certainly not Thrasymachus himself. Even Socrates complains that, distracted by Thrasymachus’ praise of injustice, he erred in trying to argue that justice is advantageous without having first established what it is (354a–c). Instead of defining justice, the Book I arguments have taken as their target Thrasymachus’ assumptions about practical rationality and advantage or the good, deployed in his conception of the ‘real ruler’. Socrates’ larger argument in Books II-IX will also engage with these, providing substantive alternative accounts of the good, rationality, and political wisdom. However, this larger-scale vindication of justice is presented as a response not directly to Thrasymachus, but to the restatement of his argument which Glaucon and Adeimantus offer (in the hope of being refuted) in Book II. And since their version of the immoralist position departs in significant ways from its inspiration, it is somewhat misleading to treat the Republic as a whole as a response to Thrasymachus. Rather, this division of labor confirms that for Plato, Thrasymachean debunking is dialectically preliminary. It is useful for its clearing away of conventional assumptions and hypocritical pieties: indeed Socrates’ later arguments largely leave intact Thrasymachus’ initial debunking theses about the effects of just behaviour and the manipulative function of moral language (unless you count a strikingly perfunctory appendix to the argument in Book X, 612a–3e). His role is simply to present the challenge these critical insights lead to; for immoralism as part of a positive vision, we need to turn to Callicles in the Gorgias. 