Humanity has long pursued an elixir of youth, and dreamed of eternal life. For the Abrahamic faiths physical immortality was lost in the Garden of Eden, with only the soul remaining of permanence. More recently, futurists and thinkers have speculated about the possibilities of radical life extension.

For neuroscientist Ariel Zeleznikow-Johnston there is another alternative, however. He believes that the human brain could be fully mapped and digitally reproduced – with the first part of that process possible within a century. Once your brain is modelled, and you die, you might think of it as a kind of time travel into the future.

Also discussed: what is ageing, identity and consciousness? And why, given we live in an age of comparative comfort, are so many becoming socially disillusioned?