Unconscious inference, or unconscious conclusion, is part of a theory on visual perception that says that human vision is incomplete and details are inferred by the unconscious mind to create a complete picture. It's like our brains are adapting to the loss, and it is filling in the blanks, sort of like a 'connect the dots' game. The world has provided us with a lot of existing forms of magical illusions. Sometimes, we don't always notice them. Some of them, we probably see every day.