The first time I reached past the sheer horror of the concept of death and wondered what the experience of dying may be like, I was about 15. I had just discovered gruesome aspects of the French revolution and how heads were neatly cut off the body by a Guillotine. Words I remember to this day were the last of Georges Danton on April 5, 1794, who allegedly said to his executioner: “Show my head to the people, it is worth seeing.” Years later, having become a cognitive neuroscientist, I started wondering to what extent a brain suddenly separated from...