Reality is merely an illusion, albeit a very persistent one.

At a psychology conference where I was speaking, I went to an exhibit where companies displayed their products for education, research, and clinical practice. One company was offering demonstrations of a virtual reality system used for the treatment of acrophobia, the fear of heights. I decided to try it out. After I stepped onto the platform next to the computer, put on the goggles, and the company representative turned on the machine, I found myself on the roof of a building, several floors up. The scene appeared rather cartoonish, but as I looked at the street below, I certainly felt that I was up in the air. “Do you want to go higher?” the operator asked. When I said yes, I suddenly found myself twice as high as before. The transition was a bit disorienting. As I turned my head, I could now look out across the cityscape, scanning the rooftops of some of the buildings surrounding me. “Do you want the next level?” the operator asked again. Curious about how far this could go, I agreed. Now I found myself thirty or more stories up, with all of the rooftops of nearby buildings far below me. Looking down beyond my feet perched on the edge of the roof, the street looked a scary long distance below. My legs felt wobbly and weak. I was a bit dizzy. “How about the next level?” the operator asked once again. “No thanks,” I replied.