Robots at the museum, but for how much longer?

For me this question has always been the defining moment of Ridley Scott's sci-fi classic, Blade Runner. Deckard, the policeman anti-hero played by Harrison Ford, has just discovered that Rachel, the self-possessed personal assistant to the founder of the Tyrell Corporation, is in fact one of the company's advanced replicants: a robot. His question to Dr Eldon Tyrell is loaded with the certainty of bigotry -- that repeated'it'. But Deckard's uncertainty about Rachel, and the essential differences between humans and machines, is just the beginning of a process of disorientation that pursues him all the way to the film's brutal but surprising climax. That we have yet to reach the dark dystopia of Blade Runner in real life is pretty obvious -- just look around you. It is also obvious from the nonetheless intriguing robotics exhibition that opened a few weeks ago at the Science Museum in London.