Theoretical physicist Stephen Hawking with his sister Mary at the premiere of the documentary Hawking in Cambridge. (Agencies)
Stephen Hawking has said he believes brains could exist independently of the body, but that the idea of a conventional afterlife is a fairy tale.
Speaking at the premiere of a documentary film about his life, the theoretical physicist 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 on to a computer and so provide a form of life after death.
"However, this is way beyond out present capabilities. I think the conventional afterlife is a fairy tale for people afraid of the dark."
The 71-year-old author of A Brief History of Time, who earlier this week backed the right for the terminally ill to end their lives as long as safeguards were in place, was diagnosed with motor neurone disease at the age of 21 and given two to three years to live.
"All my life I have lived with the threat of an early death, so I hate wasting time," Hawking said on Thursday night, using the computer-generated voice he controls with a facial muscle and a blink from one eye.
The documentary explores the headlong rush of a brilliant schoolboy with illegible handwriting who enjoyed the dilettante life of Oxford University before illness sparked a lifelong frenzy of discovery about the origins of the universe, which began as a graduate at Cambridge University and has astounded the world.
The film premiered in the same year as the release of his autobiography, Stephen Hawking: My Brief History.
His sister Mary says in the film that her brother was highly competitive and curious about everything in a household which friends described as very academic, and explains how she received a doll's house as a present when they were children, to which Stephen immediately added plumbing and electricity.
She told Reuters that life with her brother was engaging, exciting and occasionally frustrating. "It's a waste of time arguing with Stephen, he always manages to turn the argument round," she said.
The film goes back to his childhood and his student days and shows the scientist, who uses a wheelchair, at home with carers. It also explores his family life with first wife, Jane, and their three children, the breakdown of their marriage and his subsequent marriage to one of his carers.
Jane appears on camera to explain how the pressures of caring for the children and the increasingly disabled Hawking became even worse once full-time nurses were brought into the home, obliterating any privacy.
His second wife and former nurse, Elaine Mason, does not appear in the film, and Hawking portrays their 1995-2007 marriage with a few pictures and a brief description.