Republic Bk VI, VII EP 19 Analogy of the Sun

Socrates tells Glaucon that philosophers should be kings because only they have access to the Form (concept) of the Good. The concept of Justice cannot be understood unless one understands its relationship with the Form of the Good. In order to explain this relationship, Socrates turns to an analogy -- the Sun and the power of the sun to shed light on things and make them visible.