Philosophers desire to know Knowledge of is of what is in an unqualified sense. It is about what is permanent and real belief or opinion is about what is part real, what is constantly varying, imperfect, qualified. belief or opinion is about what is part real, what is constantly varying, imperfect, qualified.

Why suppose philosophers make better rulers? Just as a painter can make good likeness if they see what they are supposed to be painting, so a ruler can make a city just, only if the ruler knows what justice is. If you rule on the basis of belief, you are like a painter painting a mountain, who has never seen a mountain. Cf. 484c-d

Socrates also explicitly connects the philosophical nature to the virtues. People who love knowledge will have their desires channeled into learning, and not be intemperate. They will not overvalue life– they will be courageous. Since they don’t love money, they won’t be unjust.

Adeimantus’ objection Its hard to argue against you Socrates, but most people when they hear you speak will think you must have tricked them. Look around you, see the people who actually are philosophers. The best are useless, and most are cranks or “completely bad.”

Why the best philosophers are useless: the simile of the ship Imagine a ship with an owner who is almost deaf, almost blind, and does not know much about seafaring. Imagine also sailors, who quarrel will one another to become captain. The sailor who is best able to persuade the owner to make them captain—this person is called a navigator, a true captain.

On the ship, “Navigation” is not the art of piloting a ship, but the “art” of persuasion. You are a good navigator, captain, if you can get the ship owner to let you be captain. People who claim you need to know where the north star is, or how to read charts and weather—they are useless. They are not made use of in the ship.

The ship is like the city The ship owner is the people. The sailors are politicians The useless stargazers are the philosophers. The best philosophers are useless because the city does not use them, not because they don’t have useful knowledge.

The simile of the ship and democracy The smile of the ship illustrates Plato’s view of democracy. Instead of valuing knowledge, democratic government’s value persuasion. The ability to get elected, or get policies passed by the assembly of the people But it is one thing to persuade someone, another to actually know what is best.

Does The simile apply to contemporary politics Politicians poll people to decide what they want, and then make policies suited to those desires. A good politician is someone who can persuade, who can get elected. Just like the pseudo captains in Socrates’ ship.