"Aldous Huxley did his best to argue us out of the view that a chemically conditioned spiritual experience is false—and he did so long before we knew anything about cannabinoid or opioid receptor networks….He points out that mystics have always worked systematically to modify their brain chemistry, whether through fasting, self-flagellation, sleeplessness, hypnotic movement, or chanting.† †Huxley suggests that the reason there aren’t nearly as many mystics and visionaries walking around today, as compared to the Middle Ages, is the improvement in nutrition. Vitamin deficiencies wreak havoc on brain function and probably explain a large portion of visionary experiences in the past."