Republic derives coherence from its thematic focuses as well as its "plot" development. As is natural in a conversation about justice and "right conduct," the concern for human excellence (arete) pervades the text. Its treatment of arete plainly responds to works like Iliad and Odyssey and the general values of Hellenic culture. Against their "lessons," it seeks to redefine and limit what is meant by arete, so as to exclude from its definition all notions of material success and identify it solely with what we would call "moral excellence" or "virtue."