Killer robots and digital doctors: how can we protect society from AI?

Elon Musk, founder of SpaceX, Tesla and PayPal, is worried about killer robots. "You know those stories where there's the guy with the pentagram and the holy water, and he's sure he can control the demon?" he has warned. That "unfriendly AI", as it is known in tech circles, would not be a boon for humanity is an easy cause to get behind. But unlike Musk – a tech entrepreneur who stands to make huge financial gains from AI in the short term – most of us don't have the luxury of taking the long view. The defeat, last week, of one of the world's strongest Go players, Lee Sedol, demonstrates the qualitative leap in AI that has already taken place.