Several physicists, cosmologists and technologists are now happy to entertain the idea that we are all living inside a gigantic computer simulation, experiencing a Matrix-style virtual world that we mistakenly think is real.
Our instincts rebel, of course. It all feels too real to be a simulation.
In June 2016, technology entrepreneur Elon Musk asserted that the odds are "a billion to one" against us living in "base reality".
Similarly, Google's machine-intelligence guru Ray Kurzweil has suggested that "maybe our whole universe is a science experiment of some junior high-school student in another universe".
What do you think about?