Earlier this year, 116 technology luminaries signed an open letter (PDF) imploring the United Nations to ban "lethal autonomous weapons systems," warning that they would "permit armed conflict to be fought at a scale greater than ever." According to the Independent, it "marks the first time that artificial intelligence (AI) experts and robotics companies have taken a joint stance on the issue." Not all observers are as concerned; Andrew Ng, up until recently Baidu's chief scientist, concludes that "worrying about killer robots is like worrying about overpopulation on Mars--we'll have plenty of time to figure it out." In the early years of the 21st century, few topics have generated more intense interest, or elicited more spirited debate, than AI, beginning with the very understanding of the term: one observer quipped this March that "there are about as many definitions of AI as researchers developing the technology." Robbie Whiting, a founder of the brand consulting firm Junior, contends that "AI is not a buzzword, and it is going to change the world."