Gyges was a shepherd in the service of the king of Lydia; there was a great storm, and an earthquake made an opening in the earth at the place where he was feeding his flock. Amazed at the sight, he descended into the opening, where, among other marvels, he beheld a hollow brazen horse, having doors, at which he stooping and looking in saw a dead body of stature, as appeared to him, more than human, and having nothing on but a gold ring; this he took from the finger of the dead and reascended.
Now the shepherds met together, according to custom, that they might send their monthly report about the flocks to the king; into their assembly he came having the ring on his finger, and as he was sitting among them he chanced to turn the collect of the ring inside his hand, when instantly he became invisible to the rest of the company and they began to speak of him as if he were no longer present. He was astonished at this, and again touching the ring he turned the collet outwards and reappeared; he made several trials of the ring, and always with the same result-when he turned the collet inwards he became invisible, when outwards he reappeared.
Whereupon he contrived to be chosen one of the messengers who were sent to the court; where as soon as he arrived he seduced the queen, and with her help conspired against the king and slew him, and took the kingdom.
– The Ring of Gyges, Plato 
What would you do in the place of Gyges upon finding a ring that would turn you invisible? Would you use it for a greater good? Or for your own personal benefit? What can we expect from humans to do with power over others?
These are some of the questions about human nature arising from Plato’s thought experiment in the Republic, and they remains as valid today as they were 2,400 years ago. The ring of Gyges has been used as a paradigmatic example when discussing ethics and it can be the perfect starting point towards a discussion about the ethics of quantum computation.