"It is vital to remember that information - in the sense of raw data - is not knowledge, that knowledge is not wisdom, and that wisdom is not foresight. But information is the first essential step to all of these."

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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. Dick