The ring of Gyges
Plato · The Republic, Book II · -380
Gyges, a simple shepherd in the service of the king of Lydia, discovers a gold ring on the finger of a corpse, in a chasm opened by a storm. He takes it and soon notices that by turning the bezel toward the inside of his hand, he becomes invisible. Armed with this power, he gets himself sent to the king's court, seduces the queen, murders the sovereign, and seizes the throne: invisible, he can do anything without ever being punished. Glaucon, who tells this story to Socrates, draws a challenge from it: if the just man and the unjust man each had such a ring, he claims, they would behave in exactly the same way. No one is just willingly, but only for fear of being seen and punished.
If you owned this ring, would you remain just? And if so, why: out of habit, out of enlightened self-interest, or because justice is worth pursuing for its own sake, even with no one watching?