The Use of Dialectic to Define Justice Through the use of Socratic dialogue, Plato has an advantage at obtaining answers by refuting other philosophers. Plato is able to achieve an answer to the question, what is justice. He derives this answer through an analogy of the ideal city. The ideal city parallels the concept of the ideal person as Plato uncovers with the aid of dialectic. Plato defines justice as a function of harmony, which must first be achieved in an individual before being extended to the city. Speaking through Socrates Plato defines justice as a philosophical understanding of excellence in the organization of society a