In The Republic there are three basic classes of people within the city, and each represents a part of the human existence. The ruling class culminates in that of the guardians, those "philosopher kings" who represent all that Plato sees as best and purest in the nature of humanity and of the philosopher. This class foregoes "the spoils" in favor of what would now be called in their honor "platonic" relationships, breeding by necessity and holding all family relationships in common. They are dedicated entirely to theory, the uplifting arts (which are not those arts of mimicry and emotion), physical and spiritual training, and all other sorts of education geared at developing the higher spirit or the rational. To a degree the guardians are so enmeshed in values of the intellect and the pure that they become nearly inhuman in their perceived perfection, forswearing power and procreation and personal riches. In short, they become not human "philosophers" but rather the living incarnations of philosophy itself, nearly abstract forms of intellect and spirit.
The subordinate class is that of the common people, which is to say the laborers and merchants and artisans. Repeatedly through out this work Socrates refers to the philosopher class as guardians or rulers of the city, and refers to the warrior class as protectors of the city. If the philosophers and warrior exist only to guard and guide "the city" it falls to reason that they are not the defining factor of the city itself. Rather, the polis must be here defined as comprised of the third class, the mass and majority of the people as constrained by the structure of the laws. Consistently in the earlier chapters as Plato decides what shall and shall not exist in his city he refers to the bodily needs of the people, such as food and shoes and clothing. The city, then, is seen to be a bundle of needs and impulses under the guidance of the philosophy incarnate or represent the erotic layer of the soul. Likewise, the city is seen as that which acts out the commands of the rulers, and realizes the visions of their work through physical labor. In short, it is here suggested that the body, which works and acts should be subjugated to the intellect that analyzes, philosophizes, and guides. The city which is the common people should be ruled in their work and actions by philosophers (or the rational) with the analytical ability to make wise decisions on their behalf.
Not only does Plato suggest that such rule is best because of political expediency or the personal need for wisdom and self-control. He additionally bases these claims on a more abstract set of ideas regarding the very nature of the universe. Plato's ideas of "forms" as described in his allegory of the cave in Chapter VII of The Republic draw less from the method of the dialogue and turns towards metaphysics. Here Socrates explains how the appearances of things in reality, from a chair to a construct of Justice, are but the shadows cast by the true form of these things in a reality beyond human perception.
In his myth of the cave, the human "city" composed of prisoners within the cave is represented as being below the sun and in the darkness away from true knowledge of the forms. These prisoners typify the human experience within the city, limited in its comprehension, and guided in its urges only by the shadows it sees. Eventually, however, a "freed" citizen comes to selectively and carefully encourage them into the light. This is the role into which Socrates casts philosophers who try to encourage others to see the essence of philosophy. As Socrates says elsewhere, no one born a philosopher can stand falsehood, and one imagines that at some point this teacher must have found the courage to break free and discover the truth for himself by ascending above, and must now be returning below to lead others to this light. However, the inmates are shown as being less than thrilled at the prospect of having knowledge. Socrates uses this example to show why there may be some instinctive rejection of his philosophies about life. It also serves as a fair counterpoint to the idea that the great city will willingly follow their antiseptic guardians and their sterile philosophy.
In truth, when the intellect and thought attempts always to guide action into appropriate paths with no concern for the suffering of the individual or the difficulty of the task, this intellect is likely to be rejected. Here the stage is set for the internal tension within the microcosm or individual that is paralleled in the macrocosm of the city. This is precisely shown in the way prisoners seem to initially reject freedom and prefer to keep their chains rather than undergo the discipline of philosophy. In exactly the same way, one assumes (by continuing the metaphor between humankind and the city incarnate) a city is likely to not respond when philosophy suggests that it should make uncomfortable and difficult changes. Perhaps it is precisely this sort of refusal by prisoner's to come out into the light that is further illustrated when Plato portrays Socrates' death at the hands of the city of Athens.
In Crito and the Apology, the reader watches as Socrates' beloved city condemns him to death and he accepts it. Not only does Socrates accept death, one might even argue that he begs for it in the Apology as he rejects the idea of banishment and claims that the city should reward him for his services rather than condemn him (Apology 36d). Like the intellect speaking to the body, Socrates takes a very high tone in addressing the city within his apologies. One very much sees in his defense the same voice that philosophers should rule any just city.
Yet after his trial and during his discussion with Crito, Socrates seems to take a different tone. Where one moment he was proclaiming that the city had no right to convict him, the next he defends the right of that city to carry out its sentence. Using a form of social contract theory, he suggests that because he has always accepted the rules of the city before, he must accept them now. Indeed, he makes a very good case for the idea that the will of the city should always dominate even over a philosopher. The philosopher, it seems, is not at all the same thing as the philosophy which comes through him like the shadow of a form through clear glass. So the city over which philosophy ought to rule has the right to kill the physical philosopher which has brought in this philosophy.
In Crito, the basic argument here is that the city (which is to say the body and its needs and actions) gave birth to the philosopher (and to the rational), and that while the philosopher could at any time have abandoned the city before his arrest, and since he has not hence he is responsible to obey her laws even into the death. While on the one hand this is rightly seen as an acceptance of the difference between the philosopher and the philosophy, it also seems to suggest that the city has the right to silence the philosophy along with the philosopher. So it seems that here is a sort of reversal to all that has come before, and that Socrates is suggesting that the intellect must at times be subservient to the body.
There are three basic ways to view this paradox. The first is to suggest that one idea is true and the other false. For example, it would be possible to say that Socrates was being facetious when he made his case against running away, and actually had other concerns. Alternately, one could argue that in the story of The Republic, Socrates specifically explains that this is only true about a city of inflamed desires, and that in a natural city (of pigs, as his detractors would say) the philosophy and the intellect would not always have tyrannical rule over the city and the body. Either way, one of his main arguments must be rejected. On the other hand, one could also suggest that neither argument was true and that they were both false! Perhaps Socrates really did present paradoxical messages because he never intended to present "truth," he merely consistently played what we now call a "devil's advocate." Perhaps he always took the contrary side in any argument, whether it is for a city ruled by pleasure or for him to save his own life.
The third option is that there is a middle ground suggested by Crito. This option is by far the soundest. Perhaps the idea that philosophy and intellect should always reign over the city and the body is an exaggeration, but not a falsehood. In Crito, one notices, Socrates faces the prospect of his death not as a philosopher but as a private citizen who has been condemned by men but not by the justice itself. He suggests that to overthrow his condemnation would not attack the men who condemned him, but would attack the law. The law, in this case, however, was a philosophy wielded by the hand of desire and the city itself. Perhaps this suggests a form of balance between thought and action, in which thought may develop schemes and value systems and guides along which action must always run (the "law" of the city) and yet the desire and needs of the body are free within those systems to do as they will even if the intellect is momentarily opposed to it. In the real world, this would suggest that philosophy must guide the lawmaking process, but that a democratic city would be capable of working within those laws even if it meant the downfall of one or another philosopher or philosophy.
Such a balance makes sense in the greater scope of Socrates' life and meaning. Throughout his Apology, he argues that a misguided fool such as himself is necessary to keep the city healthy. Contrariness is part of his nature and his function. So some philosophy may be necessary to guide, and other philosophy necessary because it must be denied. Likewise some actions and urges may be necessarily denied, while others must be necessarily honored.