The psychotic does not merely think he sees four blue bivalves with floppy wings wandering up the wall; he does see them. An hallucination is not, strictly speaking, manufactured in the brain; it is received by the brain, like any 'real' sense datum, and the patient act in response to this to-him-very-real perception of reality in as logical a way as we do to our sense data. In any way to suppose he only 'thinks he sees it' is to misunderstand totally the experience of psychosis.
Philip K. DickThe real origin of science fiction lay in the seventeeth-century novels of exploration in fabulous lands. Therefore Jules Verne's story of travel to the moon is not science fiction because they go by rocket but because of where they go. It would be as much science fiction if they went by rubber band.
Philip K. DickYou're - psychotic. There's something wrong with you." "I know," Benteley agreed. "I'm a sick man. And the more I see, the sicker I get. I'm so sick I think everybody else is sick and I'm the only healthy person. That's pretty bad off, isn't it?
Philip K. DickThere was a beauty in the trash of the alleys which I had never noticed before; my vision seemed sharpened, rather than impaired. As I walked along it seemed to me that the flattened beer cans and papers and weeds and junk mail had been arranged by the wind into patterns; these patterns, when I scrutinized them, lay distributed so as to comprise a visual language.
Philip K. DickIn one of the most brilliant papers in the English language Hume made it clear that what we speak of as 'causality' is nothing more than the phenomenon of repetition. When we mix sulphur with saltpeter and charcoal we always get gunpowder. This is true of every event subsumed by a causal law in other words, everything which can be called scientific knowledge. "It is custom which rules ," Hume said, and in that one sentence undermined both science and philosophy .
Philip K. Dick