Books V and VI take a slight detour from the immediate question of the city. The focus is primarily on defining who the philosophers are, and what they are concerned with, within the context of question of the philosopher-king as the best ruler.
Several definitions are given: “…they are always in love with that learning which discloses to them something of the being that is always and does not wander about, driven by generation and decay” (485b). To Socrates, the philosopher is an ontological creature -always concerned with what has being versus non-being. Philosophic types are souls with a memory (486d), a good learner, magnificent, charming, and a friend of truth, justice, courage, and moderation (487a).
However, this definition is contradicted by Adeimantus in his experience with philosophic types. To him they seem to be “queer” though not completely vicious, and they tend to become “useless to the cities” (487d). Socrates suggests this may be the truth. Socrates responds by invoking the image of a shipowner, as opposed to the pilot of a ship. The shipowner tends to be deaf and somewhat shortsighted, and his knowledge of seamanship is similar. Meanwhile the sailors aboard are always quarreling and believing themselves to be the best pilot, and they enchain the noble shipowner and they overthrow and rule the ship either by force or by persuasion, but for the true pilot, he must be careful and pay attention to year, seasons, stars, heaven, winds, and everything proper to the art. The sailors do not believe it is possible to acquire the art and then become the pilot. Therefore, to them the true pilot is a useless “stargazer” -note the similarity to accusations made against Socrates in the Apologia and also his claims elsewhere in the Theaetetus, about the philosophers, like Thales, being incompetent in worldly matters and falling down a well while staring up at the stars. In addition recall the characterization of Socrates and philosophy in Aristophanes’s The Clouds. Socrates invocation of the ship may be read as a response and an apology for the philosophic life against its critics. Socrates says, “…bid him blame their uselessness on those who don’t use them and not on the decent men” (489b).
Socrates answers Adeimantus’s second charge that philosophers can be “vicious” demonstrating an argument about the noble types, and the weak types. The noble types, if not reared properly, will yield greater evil than the weak types, who will yield neither greatness nor evil. In this way, improperly reared and educated philosophic types become tyrants. Philosophy is necessarily a small exclusive club, and reclusive from the many. Here Socrates cites his “daemonic” sign again as his divine inspiration. The philosophic type among the masses walks through life as if in the middle of a storm, seeing all the lawlessness around him, but is content to live his life knowing he has lived pure of injustice. However, if this man finds himself in a suitable regime, he is the ruler, though there are no cities that can handle this kind of ruler today, and the difficult question remains of which regime is best for philosophy to take hold, and how can a city take philosophy in hand without destroying itself?
First Socrates denies that it is impossible for a philosopher to rule a city. The lawgiver is like a painter -first they wipe the slate clean and then outline the city, producing the image of man. And the problem arises of the continuation of the city, as all great things run the risk of falling. Today (in the time of Socrates), the city is in decay and there is much frivolity, and not enough rigorous gymnastic and philosophic education. In this line of thinking, the idea of the good is revealed to be the greatest study, greater than the question of justice, at least for the guardians of the city. The many believe the good is equated with pleasure, while the more refined believe the good is prudent.
Near the end of the book, both Adeimantus and Glaucon attempt to corner Socrates into proclaiming what the good in itself is, but Socrates dodges the question. Socrates, then engages in a discussion of being -the ideas- which are intellected. When Glaucon does not understand, Socrates invokes the image of geometry as intellection. The four affections he outlines for the soul are: 1) intellection 2) thought 3) trust and 4) imagination.