Palo Alto, Calif.

THERE you are, peacefully reading an article or watching a video on the Internet. You finish, find it thought-provoking, and scroll down to the comments section to see what other people thought. And there, lurking among dozens of well-intentioned opinions, is a troll.

“How much longer is the media going to milk this beyond tired story?” “These guys are frauds.” “Your idiocy is disturbing.” “We’re just trying to make the world a better place one brainwashed, ignorant idiot at a time.” These are the trollish comments, all from anonymous sources, that you could have found after reading a CNN article on the rescue of the Chilean miners.

Trolling, defined as the act of posting inflammatory, derogatory or provocative messages in public forums, is a problem as old as the Internet itself, although its roots go much farther back. Even in the fourth century B.C., Plato touched upon the subject of anonymity and morality in his parable of the ring of Gyges.

That mythical ring gave its owner the power of invisibility, and Plato observed that even a habitually just man who possessed such a ring would become a thief, knowing that he couldn’t be caught. Morality, Plato argues, comes from full disclosure; without accountability for our actions we would all behave unjustly.