In the demilitarized zone dividing North and South Korea, SGR-1 robots are on patrol, equipped with cameras and radar to detect intruders as well as speakers to warn them off. If that fails, they also carry machine guns and grenade launchers.

In the U.S., the Home Exploring Robotic Butler can retrieve a book from a shelf, a meal from a microwave or a drink from the kitchen. It can even separate an Oreo cookie.

In Japan, a seal-like robot called Paro provides companionship for seniors -- and seems to ease the effects of dementia.

Over the next few decades, robots will become part of everyday life. But as they grow more sophisticated and autonomous, they'll confront situations of cultural and moral ambiguity that won't be easily resolved -- situations that people, over the millennia, have learned to navigate but that resist codification that machines can easily understand. This means robots, from the battlefield to the nursing home, will require more advanced ethical-decision-making abilities. And humans will need to think through what should happen when they cause harm.

Three challenges in particular need to be explored.

David Fuller's view The inevitable reality during a rapidly accelerating rate of technological innovation is that the capabilities of machines increase faster than most people anticipate. For a personal example, consider how impressed we were with the usefulness of our mobile phones a decade ago. However, at that time how many of us envisaged the features of today's smart phones?

Most other technologies are being developed at similar speeds. The net result of this is overwhelmingly beneficial, although we are beginning to see an inevitable downside, particularly in the realm of industrial automation and robotics. The efficient machines are replacing human workers at a faster rate than they can be re-employed in other areas of our economies and societies.

Meanwhile, robots will accomplish with increasing efficiency what they are programmed to do. This will considerably improve the productivity of our economies, to the benefit of our growing middle classes. Successful corporate Autonomies will be among the main users of technological innovation. Theoretically, developing technologies will have the potential to solve many of the world's problems, including the provision of sufficient food supplies and reducing industrial pollution.

The most dangerous problems, in human terms, stemming from our accelerating rate of technological innovation will occur when artificial intelligence eventually becomes sufficiently adept to both reprogramme and also invent ever more advanced machines, without any human help.