" Twenty minutes later, Wes is being wheeled to the recovery room. Technically speaking, anyone who makes it to a recovery room can’t have been dead. By definition, death is a destination with no return ticket. Clinically dead is not dead dead. So how do we know the near-death experience isn’t a hallmark of dying, not death? What if several minutes down the line, the bright light dims and the euphoria fades and you’re just, well, dead? We don’t know, says Greyson. “It’s possible it’s like going to the Paris airport and thinking you’ve seen France. "

― Mary Roach , Spook: Science Tackles the Afterlife