Twenty four centuries after its composition, there is no agreement on even the broad outlines of the structure of Plato's Republic, let alone the underlying meaning that Plato intended to communicate to the reader. As Aleister Crowley once quipped, "theorists have not been at a loss to explain, but they differ." And even that is putting it very mildly. Karl Popper considered it a Fascist manifesto, while Robin Waterfield has claimed that it presaged the ethical teachings of Christianity. Both scholars got things very wrong, though, and ended up complementing Hitler and Jesus in a way that neither deserved, by attributing to them a Platonism that neither possessed.
The Republic tells the story of a pleasant day on the outskirts of Athens, about twenty-four hundred years ago and change, spent by Socrates and some friends discussing the question: What is Justice? The major sticking point in their investigation turns out to be the question of whether or not "to be just is always better than to be unjust?" To put it another way: doesn't self-interest, at least sometimes, dictate that it is better to act unjustly, so long as one can get away with it?
To help frame the discussion, Glaucon (Plato's brother and one of the main discussants in the Republic) poses to Socrates (at the opening of Book II) the following three questions:
(1) "Is there not one class of things which we welcome for their own sakes, and independently of their consequences, as, for example, harmless pleasures and enjoyments, which delight us at the time, although nothing follows from them?"
(2) "And is there not also a second class of goods, such as knowledge, sight, health, which are desirable not only in themselves, but also for their results?"
(3) "And is there not a third class, such as gymnastic, and the care of the sick, and the physician's art; also the various ways of money-making -- these do us good but we regard them as disagreeable; and no one would choose them for their own sakes, but only for the sake of some reward or result which flows from them?"
Socrates readily assents to this threefold classification, but asks Glaucon what his point is. And then Glaucon asks Socrates to which of the three classes Justice belongs. Socrates responds that it belongs to the second class (which Socrates calls καλλίστῳ, kallisto, "the fairest"), because Justice is something that is desirable both for its own sake and for the sake of its results.
Glaucon then observes that, nevertheless, "the many are of another mind; they think that justice is to be reckoned in the troublesome class [the third class above], among goods which are to be pursued for the sake of rewards and of reputation, but in themselves are disagreeable and rather to be avoided."
Socrates agrees that, yes, obviously, this is the way that Justice is viewed by most. But then Glaucon pleads with Socrates to convince him of the rightness of the view that Justice is good both in itself and because of its results -- because this is what Glaucon feels should be the case. For, while Glaucon wants to believe that Justice is always better than injustice, he also finds it impossible to definitively answer the cynical arguments of "the many" who hold that "the life of the unjust is after all better far than the life of the just", because (again, in the view of "the many") it is a troublesome burden to have to act justly, and the truly free man will always act according to his own desires and best interests, which are often at odds with Justice.
Having laid the groundwork and set the scene, Plato places into Glaucon's mouth the basis on which the inquiry concerning Justice and injustice will now proceed: "I want to know what they are in themselves, and how they inwardly work in the soul."[358b] In order to further this end, Glaucon declares that he will defend "to the utmost of my power" what he and Socrates have agreed is the "common view" of Justice and injustice, namely that "all men who practise justice do so against their will, of necessity, but not as a good."
It is important to emphasize that Glaucon is not at all playing devil's advocate. Rather he is genuinely giving voice to his own innermost doubts. In doing so he demonstrates the most distinctive and necessary virtue of a student of philosophy, which is the opposite of self-deception: ruthless self-honesty. Glaucon wishes he did not have these doubts, but he realizes that so long as these doubts remain unanswered, they will prevent him from consistently acting in accordance with what he believes to be true, but of which he is not genuinely convinced.
The Republic, therefore, turns out to be (in addition to the many other things that it is) an extended exercise in applied Socratic epistemology. That is to say, Glaucon already possesses "true belief" (ἀληθῆ δόξαν), but he lacks a corresponding "account" (λόγος), that is, an explanation of why this belief is true. These terms are found in Plato's dialogue on epistemology, the Theaetetus, where one of the proposed definitions for knowledge is meta logou alêthê doxan ("true belief combined with logos"). It is precisely this logos that Glaucon is lacking and that he urgently seeks from Socrates. The only way Glaucon can accomplish this is by calling up from his own psyche every objection and doubt that he can find there.
It is, in fact, somewhat controversial whether or not the formula meta logou alêthê doxan can be taken as "Plato's theory of knowledge." The Theaetetus is an aporetic dialogue, that is to say, every proposed answer to the question "what is knowledge?", including "true belief combined with logos", is rejected by Socrates (and, as usually happens, Socrates also convinces his fellow investigators on that day to reject each proposed answer as well).
My own opinion on this matter is in many ways close to that of Rosemay Desjardins, who has argued that Plato's distrust of words, and of the written word in particular, led him to insist on demonstrating that even statements that, if interpreted properly, convey Plato's own understanding of basic philosophical principles, are still quite vulnerable to misinterpretations which lead to philosophical conclusions that are demonstrably false.
In her essay, Why Dialogues? Plato's Serious Play, Desjardins quotes from Plato's Charmides, where Socrates himself says that he feels the need "to investigate the meaning of my own words -- from a fear of carelessly supposing at any moment that I knew something while I knew it not." [166c8-d2] Desjardins then elaborates on this point as follows:
This is why characteristic Platonic doctrines are themselves subjected to cross-examination and under certain circumstances suffer elenchus. Thus, Meno's understanding of the Platonic claim that virtue is knowledge is shown to be indefensible, Theaetetus' understanding of the Platonic doctrine that knowledge involves true opinion and logos is shown to be inadequate, and young Socrates' understanding of the doctrine of forms is shown to be fragile under cross examination by Parmenides.In the specific case of the "Platonic doctrine that knowledge involves true opinion and logos", Desjardin has also produced a full, book length study (The Rational Enterprise: Logos in Plato's Theaetetus) devoted to demonstrating that this is, indeed, a "Platonic doctrine", despite the fact that the dialogue ends with Socrates and everyone else scratching their heads and claiming to have not discovered an answer to question what is knowledge?
[Platonic Writings/Platonic Readings, ed. by Charles Griswold, p. 115]
In my opinion, though, what Plato manages to do in the Republic, is to present a much more forceful "account" than that which is found in the Theaetetus, of why this logos is so crucial to genuine knowledge: a logos of logos itself, if you will. This two-fold logos is nothing less than the missing link that resolves the so-called Socratic paradox, for it explains how one can wish to act rightly and still fail -- while also indicating the way out of the paradox. If one has only the alethe doxan (true belief) about Justice, but without the logos, then one will be faced with the miserable prospect of believing in Justice, but being incapable of acting Justly. This is precisely the situation that Glaucon finds himself in at the opening of Book II, and it is in order to extricate himself from this situation that he seeks assistance, in the form of logos, from Socrates. This shows that the so-called "Socratic paradox" is only paradoxical when true belief, alone (without logos) is mistaken for true knowledge.
One of the more common statements of the paradox is "no one does wrong willingly (or knowingly)." A somewhat longer statement of the paradox is found in Xenophon's Memorabilia, iii.9.5:
Socrates said that justice, moreover, and all other virtue is wisdom. That is to say, things just, and all things else that are done with virtue, are "beautiful and good"; and neither will those who know these things deliberately choose aught else in their stead, nor will he who lacks the special knowledge of them be able to do them, but even if he makes the attempt he will miss the mark and fail. So the wise alone can perform the things which are "beautiful and good"; they that are unwise cannot, but even if they try they fail. Therefore, since all things just, and generally all things "beautiful and good," are wrought with virtue, it is clear that justice and all other virtue is wisdom.Sometimes one encounters reference to multiple Socratic paradoxes: (1) no one does wrong willingly, (2) virtue is knowledge, and (3) the virtues are one. A little reflection (especially if one reads Xenophon's words above) shows that these are all restatements of a single principle. Each way of stating the principle has some merit on its own, but they do not constitute separate principles (or paradoxes).
We cannot afford to lose sight of the fact that only "those who know these things", that is, those that know "things just, and all things else that are done with virtue", they alone are able to choose to act justly, wisely, well, and virtuously (which all amount to the same thing), and not only will they be able to so choose, but they do so choose. Since virtue is wisdom, the fact that the wise act Justly is no longer a a paradox as much as it is a tautology. On the other hand, those who are ignorant of this "special knowledge" cannot act Justly, and "even if they try they fail."
[The pic of the relief of Bendis with torch race victors is from Phil Harland's website here.
The pic of the statue of Artemis Bendis is from wikipedia here.
The map of Athens showing the Pireaus is from Karl Galinsky's online resources for his Intro to Ancient Greece class at U Texas here.]