Verified answer

Short summary of the Myth of the Ring of Gyges: The Ring of Gyges is a legendary artifact that, when worn, makes the wearer invisible. Plato (in the guise of Socrates) puts forth the question of whether a man would do immoral things if he had the ring. In other words, do people behave morally because others are watching, or would they behave morally even if no one could see them?

Socrates' partner in this dialogue, Glaucon, suggests that people are only moral because they know that others are watching, and thus morality is only a matter of social custom.

As usual, it takes Socrates a lot of arguing to make a fool of Glaucon and make his point, which is that morality is NOT a social construct. Instead, a man only preserves his rationality and self control by behaving morally, and to fail to behave morally allows a man to be taken over by his baser cravings and desires. To be thusly overtaken makes a man less than a man.

What this myth means for ethics is that a "right thing" in each situation exists, and you should always do the right thing, even if no one is looking/you know you won't get caught.

You must know that no one can answer your last question because it is incomplete.