The Republic is about Plato’s ideas of justice—not in terms of criminal law, but rather how to maximize happiness by living a life that is just both internally and externally. He talks about both a city and a soul, comparing the two, setting out his idea of both human nature and how people should live, with the soul a microcosm of the city. His ideal city, as with the ideal soul, balanced the three parts of human nature: reason, passion, and appetites. By arranging the city justly, it would also maximize justice within the souls of the inhabitants.
