Once upon a time, long ago, long before H.G. Wells penned his science fiction classic, The Invisible Man, long before Tolkien created his epic saga of the one ring that would rule them all, there lived a shepherd by the name of Gyges. Now, this Gyges was a humble man in the service of a king, a mere shepherd whose only desire was to tend his flock and live peacefully. But one day, while tending his sheep and their lambs, Gyges' world was shaken by a great storm that opened up a huge crack in the earth.
Curious as to what lurked in the bowels of the earth, Gyges descended and found a hollow bronze horse with doors on its side. Inside the tomb of a horse was a naked body with a gold ring. Gyges was not wealthy, so he took the ring and put it on his finger. He thought little of it, until he was meeting with other shepherds and discussing the monthly report to be sent regarding the health and stocks of the flocks to the King of Lydia. Out of boredom, he absently turned the ring to the palm of his hand.
Instantly, the shepherd became invisible. He realized that the other parties no longer acknowledged his presence, they could neither see nor hear him, but when he turned the ring back to its original location on his hand, he was visible again. Gyges was a changed man as a result, and not simply because of his acquisition, physically, of his new superpower. Never having been overly ambitious before, he made his way into the palace, seduced the queen by becoming visible again, and killed the legitimate king through the use of the ring. Thus, he became the ruler of the land, not by right, or by democratic acquisition, but purely by fear and might, and by becoming extraordinary, rather than ordinary, in his relationship to other men.
The moral of the tale, says the narrator Glaucon in Book II of Plato's "Republic" is that when one supposes, "now that there were two such magic rings, and the just put on one of them and the unjust the other; no man can be imagined to be of such an iron nature that he would stand fast in justice. No man would keep his hands off what was not his own when he could safely take what he liked out of the market, or go into houses and lie with any one at his pleasure, or kill or release from prison whom he would, and in all respects be like a God among men." In other words, everyone would do the exact same thing as the shepherd Gyges, were he given Gyges' ring. Gyges was no better or worse than any other man, he simply was given the chance, opportunity, and power to be strong, and he seized the day and got his queen and kingdom. (360b-c)
Thus, in Glaucon's view, the only thing that keeps men honest is the laws and the social judgments of other men. Laws protect the weak, thus the weak desire laws, while the strong only desire to rule, and with as little legal restraint as the masses will allow them. The only reason that Gyges was just and meek in his actions before getting the ring was that he was a poor shepherd, dependant upon the whims of others. And thus, says Glaucon, "then the actions of the just would be as the actions of the unjust; they would both come at last to the same point. And this we may truly affirm to be a great proof that a man is just, not willingly or because he thinks that justice is any good to him individually, but of necessity, for wherever any one thinks that he can safely be unjust, there he is unjust." (360c)
However, such a reading ignores the question of why the original king of Lydia was a better king than Gyges -- might it be because he was more conscious of the need for social approval in leadership, and less apt to be swayed by sensuality, in the form of the queen, and the approbation of the masses, and the trappings of ruling a land, simply because he had grown accustomed to these gifts? Perhaps Gyges, because he experienced social weakness before social strength, acted as he did.