Andrew Greeley in his book Ecstasy! A Way of Knowing (Englewood Cliffs, NJ: Prentice Hall, 1974) reports that about 50 percent of a sample of 1,500 adult Americans affirm having had at least one such experience; see his tables of data on pages 139–142, which also report the “triggers” of the experiences. The title of his book succinctly makes the point I am making: Ecstatic religious experience is a way of knowing, and not simply an altered state of consciousness or intense feeling. The same claim is made by William James in his classic study, The Varieties of Religious Experience, in which he observes that mystical experiences have a strong noetic quality (see lectures 16 and 17).