The Republic

Plato's longest and most widely read dialogue, staged as a conversation led by Socrates that sets out to define justice and, in the course of doing so, sketches an entire ideal city ruled by philosopher kings who have grasped the Form of the Good through years of education in mathematics and dialectic. The dialogue divides the soul into three parts, reason, spirit, and appetite, and argues that justice in the individual, like justice in the city, consists in each part performing its proper function under the rule of reason, a structure meant to make the case that justice is worth having for its own sake and not merely for its consequences. Along the way the Republic contains some of the most famous images in the Western canon, including the analogy of the sun, the divided line, and the allegory of the cave, in which prisoners who have only ever seen shadows mistake them for reality. The work also argues, controversially, for the censorship of poetry and for a radical restructuring of the family among the guardian class, positions that have been debated since antiquity.