How close are we to creating a Westworld?

Real robots look nowhere close to their fictional avatars, but those on show at the Science Museum ask pertinent questions about who we are and what we're doing

"How can it not know what it is?"

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.