The science of "predictive processing" reveals how our brains engaged in a constant cycle of prediction and error-correction, comparing the "expectations" generated by internal top-down mental models with the streams of bottom-up raw data coming in from the senses, the body, and surrounding environment. In other words, perception is a form of controlled hallucination, and hallucination is a form of uncontrolled (or less-controlled) perception. How else could a blind lump of meat in a silent boney cage make sense of the world?