Although Sacks tells the reader he will concentrate on “ ‘organic’ psychoses — the transient psychoses sometimes associated with delirium, epilepsy, drug use and certain medical conditions,” he includes a chapter, “On the Threshold of Sleep,” that treats hypnagogic hallucinations, the vivid imagery many people see before they fall asleep, and another, “The Haunted Mind,” which describes bereavement and traumatic hallucinations that would be classified as psychiatric not neurological phenomena. As Sacks knows, separating the physiological from the psychological is a philosophical conundrum that continues to plague both science and philosophy. But one of the pleasures of reading “Hallucinations” is understanding how complex human reality often trumps attempts to categorize it. As the 19th-century neurologist Jean Martin Charcot once remarked (and Freud recorded): “Theory is good, but it doesn’t prevent things from existing.”
more from Siri Hustvedt at the NY Times here.