Several hundred years before the birth of Socrates, Thales the philosopher was said to have fallen into a well while observing the heavens.  Thus the impractical and detached reputation of philosophers was born.  In Books 6 and 7 of the Republic the issue of the usefulness of either the philosopher or philosophy is brought up several times.  What is this uselessness, and how does the philosopher become useful?  In that earlier book Socrates admits that philosophy is indeed useless, but blames this “uselessness on those who don’t use [philosophers], not on decent men” (489b).  Later, in Book 7, we return to the usefulness of philosophy.  Socrates, although himself noting that the study of geometry has as its ‘“useful byproduct” war, chastises Glaucon for wishing to highlight the practical benefits of astronomy (527c-d).  Socrates insists that the real significance of these studies is the cultivation of the eye of the mind. 

What this points to is that if there is going to be a conversion from “uselessness to usefulness” by the study of philosophy, this change cannot come about by pandering to the currently perceived needs of the city.  Rather the city must come to see its need for something beyond the daily worries attendant on activities like farming and warfare.  And we must additionally keep in mind that Socrates is proposing a city that has the general welfare in mind, not the concerns of any individual or one group.  Yet it is precisely at this point that this concern for the welfare of the city makes it most shocking demand, according the allegory of the cave. 

In the cave, the cave-dweller, let us remember, was not liberated by his own devices, but Socrates tells us that he was released and “compelled to stand up,” “compelled to answer [what the shadows] are,” “compelled…to look at the light itself” (515c-e).  On the other hand, the philosopher, himself a liberated cave-dweller, must not live the care-free life of contemplation, he too has to return to the cave to liberate and educate the remaining captives (520b).  So for the betterment of the city, both the philosopher and “cave-dweller” must, in some sense, submit to a course of life other than what they would have normally chosen, had they not been looking to the betterment of the city.  What informs this decision and what is the guiding principle of their lives if it is not the oracle of mere personal preference? 

The answer, as it turns out, is a paradox.  Normally we expect that if we are to attend to the betterment of say, our garden, we put on our overalls in order to focus on the garden.  This is not so with the case of the polis.  In the case of the city we must fix our attention outside of the city, to things seen only by the inner eye, intellection.  Recall that in Book VI Socrates’ initial response to the charge of uselesness is to give us an image of men on a ship. He tells us that when the true pilot navigates, he looks to, “year, seasons, heaven, stars, winds, and everything that is proper to the art” (488d).  But he does not look at the ship. Nor does the philosopher in the cave look at the cave, but he attempts to focus the attention of the cave-dwellers to eventually look at the sun.  Thus it turns out that the philosopher and philosophy are extremely useful; without him and it, the entire city is unable to see or even to learn to see what they should really be fixing their gaze upon, the Form of the Good.