The original version of this story appeared in Quanta Magazine.
It is late at night. You are alone and wandering empty streets in search of your parked car when you hear footsteps creeping up from behind. Your heart pounds, your blood pressure skyrockets. Goose bumps appear on your arms, sweat on your palms. Your stomach knots and your muscles coil, ready to sprint or fight.
Now imagine the same scene, but without any of the body’s innate responses to an external threat. Would you still feel afraid?
Experiences like this reveal the tight integration between brain and body in the creation of mind—the collage of thoughts, perceptions, feelings, and personality unique to