A woman using a VR headset at SXSW, 2015. (Photo by Nan Palmero, licensed under CC BY 2.0.)

Where are you? The question is both easy to answer and not; it depends on what you think I mean. Maybe, dear reader, you would tell me you’re in Scottsdale, Arizona, or maybe you’d say you’re at home, or maybe you feel yourself to be inside your body, inside your head in fact, somewhere behind your eyes and between your ears. All these things and more—such as “I’m in my 62nd year” or “I’m in a good pla...