  In Book One, the Republic’s question first emerges in the  figure of Cephalus. After Socrates asks his host what it is like  being old (328d–e) and rich (330d)—rather rude, we might  think—Cephalus says that the best thing about wealth is that it can  save us from being unjust and thus smooth the way for an agreeable  afterlife (330d–331b). This is enough to prompt more questions, for  Socrates wants to know what justice is. Predictably, Cephalus and  then Polemarchus fail to define justice in a way that survives  Socratic examination, but they continue to assume that justice is a  valuable part of a good human life. Thrasymachus erupts when he has  had his fill of this conversation (336a–b), and he challenges the  assumption that it is good to be just. On Thrasymachus’ view (see  especially 343c–344c), justice is conventionally established by the  strong, in order that the weak will serve the interests of the  strong. The strong themselves, on this view, are better off  disregarding justice and serving their own interests directly.