The fully programmable Nao robot has been used to experiment with machine ethics. In his 1942 short story'Runaround', science-fiction writer Isaac Asimov introduced the Three Laws of Robotics -- engineering safeguards and built-in ethical principles that he would go on to use in dozens of stories and novels. They were: 1) A robot may not injure a human being or, through inaction, allow a human being to come to harm; 2) A robot must obey the orders given it by human beings, except where such orders would conflict with the First Law; and 3) A robot must protect its own existence as long as such protection does not conflict with the First or Second Laws. Fittingly, 'Runaround' is set in 2015. Real-life roboticists are citing Asimov's laws a lot these days: their creations are becoming autonomous enough to need that kind of guidance.

The Modular Prosthetic Limb will help patients to feel and manipulate objects just as they would with a native hand. Sitting motionless in her wheelchair, paralysed from the neck down by a stroke, Cathy Hutchinson seems to take no notice of the cable rising from the top of her head through her curly dark hair. Her gaze never wavers as she mentally guides a robot arm beside her to reach across the table, close its grippers around the bottle, then slowly lift the vessel towards her mouth. Only when she finally manages to take a sip does her face relax into a luminous smile. This video of 58-year-old Hutchinson illustrates the strides being taken in brain-controlled prosthetics1.

This year, several leading researchers have sounded warnings about the risks of using the CRISPR gene-editing technique to modify human1 and other species' genomes in ways that could have "unpredictable effects on future generations"2 and "profound implications for our relationship to nature" (see go.nature.com/jq5sik). Concerns are coming from the silicon sector as well. Last year, the physicist Stephen Hawking proclaimed that rapidly advancing artificial intelligence (AI) could destroy the human race. And in 2013, former Royal Society president Martin Rees co-founded the Centre for the Study of Existential Risk at the University of Cambridge, UK, in part to study threats from advanced AI. Leaders of the scientific community are ready to share the responsibility for these powerful technologies with the public. George Church, a geneticist at Harvard University in Cambridge, Massachusetts, and others wrote last year of CRISPR that "the decision of when and where to apply this technology, and for what purposes, will be in our collective hands".

Robin Li, head of China's web giant Baidu, unveils the firm's intelligent digital assistant, Duer. When Andrew Ng joined Google from Stanford University in 2011, he was among a trickle of artificial-intelligence (AI) experts in academia taking up roles in industry. Five years later, demand for expertise in AI is booming -- and a torrent of researchers is following Ng's lead. The laboratories of tech titans Google, Microsoft, Facebook, IBM and Baidu (China's web-services giant) are stuffed with ex-university scientists, drawn to private firms' superior computing resources and salaries. "Some people in academia blame me for starting part of this," says Ng, who in 2014 moved again to become chief scientist at Baidu, working at the company's research lab in California's Silicon Valley.

In March 2001, futurist Ray Kurzweil published an essay arguing that humans found it hard to comprehend their own future. It was clear from history, he argued, that technological change is exponential -- even though most of us are unable to see it -- and that in a few decades, the world would be unrecognizably different. "We won't experience 100 years of progress in the 21st century -- it will be more like 20,000 years of progress (at today's rate)," he wrote, in'The Law of Accelerating Returns'. Fifteen years on, Kurzweil is a director of engineering at Google and his essay has acquired a cult following among futurists. Some of its predictions are outlandish or over-hyped -- but technology experts say that its basic tenets often hold.

At the 24th Army Science Conference, held in Orlando, Florida last December, Ray Kurzweil gave a keynote address entitled "Warfighting in the 21st Century". Within 25 years, non-biological intelligence will match human intelligence in areas in which humans now excel, principally in pattern recognition. It will combine these abilities with the inherent advantages of machine intelligence, such as speed, easy sharing of knowledge and skills. One implication will be that we will enhance our own biological intelligence through direct connection with non-biological intelligence. Already, our abilities benefit from close collaboration with machines.

When Paul Selmer lost his right leg below the knee in a hunting accident, a doctor fitted him with a standard prosthesis that required a waist belt to swing the wooden foot with each step. Selmer remembers it feeling like a "sandbag." That was 28 years ago. The gallery owner and small-aircraft pilot is now a devotee of a high-tech device called a PROPRIO foot, which utilizes sensors, artificial intelligence and microprocessors. "I marvel at how far we've come and how far we can go," said Selmer, who was unable to fly newer planes until discovering the PROPRIO.

The past few years have shown that U.S. government intelligence goes only so far. One of the biggest challenges is recognizing vital information in foreign languages -- and acting quickly on it. That's why the military would love software that can listen to TV broadcasts or phone conversations and read Web sites in Arabic and Chinese, translate them into English and summarize the key elements for humans. But each of those steps has long bedeviled computer scientists. Perfecting them and combining them -- well, that is "DARPA hard."

The real-life equivalent of Isaac Asimov's Three Laws of Robotics (which posits that robots may not harm humans, even if they are instructed to do so) is, like killer-robot technology itself, a ways off. In April, the United Nations released a report (PDF) that recommended suspending the development of autonomous weapons until their function and application is discussed more thoroughly. Last December, the Department of Defense issued a directive on weapon systems autonomy, calling for the establishment of "guidelines designed to minimize the probability and consequences of failures in autonomous and semi-autonomous weapon systems that could lead to unintended engagements." Though the Pentagon document stresses the need for human supervision of military robots, critics claim it leaves the door open for the development of autonomous lethal robots that aren't accountable to meaningful human oversight. "We already don't understand Microsoft Windows; we're certainly not going to understand something as complex as a humanlike intelligence," says Mark Gubrud, a research associate working on robotic and space weapons arms control at Princeton.

Chinese restaurant Two Panda Deli in Pasadena, California, recruited a pair of Japanese robot waiters, Tanbo R-1 and Tanbo R-2 (for $20,000 each), to deliver Chow mein to customers and bust out disco moves. Police radio interference compelled them to splatter orange chicken and whirl furiously around in circles. Complex customer requests were also often met with the terse reply: "That's not my problem." In The Terminator, Arnold Schwarzenegger stars as a cyborg killing machine from the future programmed to go back in time, find, and kill Sarah Conner in 1984 Los Angeles.