Recently, a movie was released. It's main story is the uprising of the low ranks toward the upper class in a train, so called 'Snowpiercer', where people are born and are living. And people cannot escape from the train because of the sudden glacial age of the Earth. With the birth, one is set to be in a certain social class they cannot change forever. And the ruling powers say that the justice is kept safely when members of low rank should respect the train system itself.
  A philosopher imagine a similar thing; there was an inborn social status, hence a certain of ruling members with vested rights existed. The nation as a philosopher, Plato, a Greek Great at that time, suggested, has a class system-Governing who reign the state, Protective who defend it, and Productive who produce living material. The body consisting of three steps vertically from narrower top to broader bottom can be kept completely if the class members are to live in faithfulness with their own responsibility, and Plato called it as Justice. Members should acknowledge their own status and serve for the state. The Governing, or rulers of the nation are required to have a lot of study and learn logics and philosophies needed to enlighten their benighted people who do not see IDEA, an ideal world having perfect form of materials philosophers can only see. Their duties are well drawn by the Allegory of the Cave. In addition, the Protective, or warriors, have to ensure its security of the nation. It's not different from our times. Finally, the Productive, or workers, produce what people can use in their routine. What we need to notice is that Workers are depicted as benighted and stupid ones who do not have any political rights to manage their country due to inability to see IDEA. In other words, to Plato, democracy seems to be a political system that cannot ensure its country's direction and development because of the Common's ignorance, so instead of them, by occupying ruling crown exclusively, philosophers lead them forward at the head of the state.