Socrates adamantly denies that he can identify a single state at the time of this dialogue that might prove fruitful for the growth of a philosopher-ruler; he says that, because of his environment (the society in which he finds himself), the naturally good, budding philosopher becomes warped. But Socrates anticipates the resultant clamor from a public whom he has accused of being corrupt, and he attempts to placate that public by insisting that a philosopher-ruler would still be the ideal ruler for the ideal state.
The problem, Socrates says, for our producing a philosopher-ruler may lie in the material with which we have to work. We agree that such a ruler must be intelligent, a "quick study," ambitious in things of the mind, diligent. At the same time, the potential ruler must be disciplined, temperate, reliable. But intelligent people may be intemperate and unreliable, and they may lack courage. Reliable people, conversely, are often indolent and bored when facing intellectual tasks; such people are often ignorant and may be stupid. Citizens who possess all the qualities required in a philosopher-ruler will be in a distinct minority.
Thus it is that candidates for the capacity as ruler will have to be more thoroughly educated than we had thought; they will have to pursue a more rigorous intellectual training so that they can attain knowledge of the real.
Glaucon asks Socrates if he means that the potential rulers are to have knowledge of the Forms. Socrates replies that the rulers must possess knowledge of Goodness, for logically that is the sole way a man may recognize the goodness of, say, Justice and Beauty.
