Back when I taught at Yale, I used to give a quiz about Plato’s Republic in the first class meeting for one of my upper-level seminars. The students were all supposed to have taken at least one prior course in which the Republic was read, and I wanted to see how well they remembered it. (I also wanted to show them that I meant business.) The quiz had two questions: What is the Republic’s ’noble lie’? What is its political purpose?

Nearly everyone got the first question right, at least in broad outline. The noble lie is one of the things that’s remembered by everyone who’s ever read The Republic — that, and the notion that none but philosophers are fit to be kings.

The noble lie is the public deception that Plato has his Socrates propose at the end of the Republic’s Book III. It is a myth about human origins — in the most literal immediate sense: a myth about where babies come from. According to this myth, the city’s babies are not born from the bodies of human mothers, but from out of the earth, after having been formed in an underground mineral womb. All share a common maternity — the ground under their feet — yet their souls and their destinies differ, depending on their mineral composition. Those with gold in their souls are destined for the ruling elite. Those whose souls are made up of silver are to be denied that distinction, but are fit to bear arms. Everyone else — the general populace — are left to their private occupations, befitting the baser metals of which they are made.

From their earliest childhood, the citizens of Socrates’ city are to be taught that they share the same geological parentage. Yet for some unexplained reason, the specific type of metal in their soul forbids them to come into contact with certain substances or pratice certain activities. The commoner sorts — their souls made of iron and bronze — are not to bear arms, nor take part in government. That means they are left to money-making occupations — agriculture, crafts, and commerce. Their gold- and silver-souled brethren, on the other hand, are not to touch money, or possess anything bought with it. Their lodgings and sustenance are to be provided to them by the state, on a communal basis.

So much for the first question. Everyone who’s read The Republic remembers this, more or less. How about the next one? If that’s the noble lie, what’s its political purpose? What rationale does Plato put in Socrates’ mouth, when proposing this myth’s propagation?

I’d get the same answer from almost every student. It didn’t matter if they’d read the Republic in a philosophy course, or a course in political theory. It didn’t matter if they’d read it in a course taught by me. In all likelihood, it’s the answer that comes to mind to anyone reading this. The political purpose of the noble lie is to persuade the common citizens to accept the rule of the guardians (the philosopher kings). It’s propaganda designed to inculcate submission and subordination. It’s an ideological prop for a regime of benevolent despots, designed to make the people accept their subordination.

Nope. Plato isn’t interested in any of that. For better or worse, he takes it for granted that in a well-ordered state — or in a disorderly one, for that matter — some few must rule, and the others obey. He takes it for granted, too, that most people are satisfied with that arrangement, most of the time, so long as they aren’t threatened, or despoiled of their possessions — or would be, anyway, if not over-excited by self-serving demagogues. Be that as it may — the noble lie isn’t intended for them. Plato has Socrates introduce the noble lie at a specific juncture of his argument, to address a different problem entirely.

The problem has nothing to do with the people resenting or chafing against the guardians’ rule. The noble lie isn’t directed at the common people at all, except incidentally. It’s directed at the elite. In particular, it’s directed at the elite’s silver class, the warrior caste. The stated purpose of the noble lie is ensure that this class be kept from taking advantage of their armed strength to despoil the city, by teaching them to shun all contact with money, and the things that money can buy. The myth appeals to this caste’s love of honor — prestige — while also slyly insinuating the belief that the essence of prestige is to dine in a mess hall, and live in a barracks.

The bit about the noble lie comes at the end of a long discussion (taking up much of book II, and all of book III) concerning the selection and training of those who are to guard the good city. (At this point in The Republic, nothing has been said about ruling — “guarding” is treated as a matter of defending against enemies.) When Socrates first raises this issue, he compares guardians to well-bred sheepdogs. Like shepherds’ dogs, the city’s guardians must possess sufficient “spiritedness” (thumos) as to be ready and able to fight off the enemies of the city, and yet they must show perfect gentleness to its friends (that is, the law-abiding citizens).

Socrates goes on in great deal about the proper training for these guardians, which — true to his sheepdog analogy — is essentially a matter of properly disciplined habituation. (Only later in the Republic does it become fully clear that this is all just the first phase of the much longer training of those who are to serve as the city’s true, ruling guardians — the philosopher-kings.) Unexpectedly, at the end of that long discussion, it emerges that Socrates himself has little confidence in this educational program’s results. Out of every cohort selected to receive this rigorous training, only a fraction will prove worthy and reliable guardians. The would-be guardians are to be subjected to various (unspecified) trials and tests, so as to identify those “who believe throughout their lives that they must eagerly pursue what is advantageous to the city [i.e., the city’s good] and be wholly unwilling to do the opposite.” Those who are to guard the city must be counted upon, above all else, to “guard” their belief that what is best for the city is best for themselves; they must prove themselves able to withstand the seductions of desires or fears as might becloud or confuse this belief.

Socrates and his companions seem to take it for granted that only a few of the would-be guardians will satisfy this criterion; when put to the test, the rest will prove not to be so reliable after all. And yet Socrates also assumes that these unreliable ones, too — or some of them, anyway — must be kept in the service of the city. For reasons not yet explained, the true guardians must count on retaining the help and support of the others.

(A part of the equation that emerges only later in the Republic: those who bear arms for the city are younger than the true guardians — too young to have been fully tested. Socrates cannot explain this properly at this point in the dialogue, for it is only later, in Book VII, that we are given the reason why the true guardians will have to be much older men and women – it takes that long to be educated as a philosopher, to show oneself worthy of that education.)

The device is needed, Socrates implies, precisely because the armed cohort otherwise cannot be counted upon to identify their own best interest with that of the city; the myth of the metals is to fortify that identification by appealing to their sense of honor — that same ‘spiritedness’ which is the outstanding trait of this caste.

Although Socrates recommends having the noble lie propagated everywhere in the city, this is chiefly in order to increase the likelihood that it will take hold among the warrior caste. It’s a drastic solution, and it isn’t so clear that Socrates himself thinks it’s likely to work. What’s interesting is that he’s so acutely aware of the peril in the problem.

“The most terrible and most shameful thing of all is for a shepherd to rear dogs to help him with his flocks in such a way that… they do evil to the sheep and become like wolves instead of dogs.”

δεινότατον γάρ που πάντων καὶ αἴσχιστον ποιμέσι τοιούτους γε καὶ οὕτω τρέφειν κύνας ἐπικούρους ποιμνίων, ὥστε ὑπὸ ἀκολασίας ἢ λιμοῦ ἤ τινος ἄλλου κακοῦ ἔθους αὐτοὺς τοὺς κύνας ἐπιχειρῆσαι τοῖς προβάτοις κακουργεῖν καὶ ἀντὶ κυνῶν λύκοις ὁμοιωθῆναι.

Republic 416a