Human beings pursue alluring visions. The vision quest is an age-old phenomenon. Contemporary religions are more skeptical. Conservative mysticism shuns spectaculars, including hallucinated apparitions. Indeed, the Christian mystical tradition holds that if you have seen God clearly, you have not really seen God. Buddhist injunctions against seeing Buddha are even more emphatic. Herein, hallucinations, locutions, and ecstasies will be viewed as phenomena suggesting only that parts of the brain are in an excitable, quickened state.

From James H. Austin’s Zen and the Brain, Cambridge, Massachusetts: The MIT Press, 1999 (first published in 1998), pp. 383-384.