Magic works because the human brain has a hardwired process of attention and awareness "that is hackable." Magicians can hack your brain. At any given moment, most people are blocking out about 95% of what is going on around them. During a visual illusion, you may see something that isn't there, not see something that is, or see something that differs from what is there. Your brain's pereceptions contradict the physicial properties of what you see. (Macknik, Stephen L. PhD and Susana Martinez-Conde PhD. Sleights of Mind. p 6-10. NY: Henry Holt and Company, 2010.)