"Normal waking consciousness feels perfectly transparent, and yet it is less a window on reality than the product of our imaginations--a kind of controlled hallucination. This raises a question: How is normal waking consciousness any different from other, seemingly less faithful productions of our imagination--such as dreams or psychotic delusions or psychedelic trips? In fact, all these states of consciousness are "imagined": they're mental constructs that weave together some news of the world with priors of various kinds."