Professor Stephen Hawking has predicted that it could be possible to preserve a mind as powerful as his on a computer - but not with technology existing today.
The cosmologist, 71, said the brain operates in a similar way to a computer programme, meaning it could in theory be kept running without a body to power it.
Prof Hawking was speaking after the premiere of a new biopic about his life, which he narrates himself, at the Cambridge Film Festival.
Asked about whether a person’s consciousness can live on after they die, he said: “I think the brain is like a programme in the mind, which is like a computer, so it’s theoretically possible to copy the brain onto a computer and so provide a form of life after death.
"However, this is way beyond our present capabilities. I think the conventional afterlife is a fairy tale for people afraid of the dark."
The film tells the story of Prof Hawking’s life, from his childhood in Oxford to his current home in Cambridge where he lives with the help of a group of carers.
It addresses how he moved from being diagnosed with motor neurone disease at the age of 21, and being told he had three years left to live, to becoming the world’s most famous living scientist.
Addressing his condition, which has afflicted him for half a century, he says in the film: “Keeping an active mind has been vial to my survival,as has been maintaining a sense of humour.”
Speaking before the premiere on Thursday, Kip Thorne, the American physicist and a close friend of Prof Hawking, said: “I think his handicap allowed him to do science he may not otherwise have done.
"He is the most stubborn man I know and that stubbornness and that drive is in part motivated by his disability."