From driverless cars to "carebots", machines are entering the realm of right and wrong. Should an autonomous vehicle prioritise the lives of its passengers over pedestrians? Should a robot caring for an elderly woman respect her right to life ahead of her right to make her own decisions? And who gets to decide? The challenges facing artificial intelligence are not just technical, but moral - and raise hard questions about what it means to be human.

(image: PaPeRo communication robot at the Robodex trade show in Tokyo, Japan, 18 January 2017. Photo credit: Tomohiro Ohsumi/Getty Images)