‘A grand illusion’ is concerned with the nature of illusion. Emotional decision-making, intuition, subliminal perception, and change and inattentional blindness are discussed along with traditional theories with their inner representations. These theories cannot explain how those representations become conscious experiences, why some visual representations are ‘in; consciousness whilst most are not, or why we seem to be someone looking at the representations. They are compared with grand illusion theory and the sensorimotor theory of vision proposed by psychologist Kevin O'Regan and philosopher Alva Noë, which turns the problem upside down, making the viewer into an actor and the visions into actions. The sensorimotor theory must now explain how actions can become subjective experiences.