Mystical experiences, whether accessed via psychedelic substances or not, are the quintessential examples of religious experience. Long before writers like Koch and Oates and Woolf came along, the pioneering psychologist and philosopher William James examined the mystery and complexity of consciousness in The Varieties of Religious Experience: A Study in Human Nature — the 1902 masterwork based on his Gifford Lectures, in which James explored science, spirituality, and the human search for meaning.
“Our normal waking consciousness… is but one special type of consciousness, whilst all about it, parted from it by the filmiest of screens, there lie potential forms of consciousness entirely different… No account of the universe in its totality can be final which leaves these other forms of consciousness quite disregarded.”
James delivered these lectures on natural theology at the University of Edinburgh, Scotland between 1901 and 1902. The Varieties of Religious Experience, an investigation of different forms of religious experience, including theories on the Higher Thought movement, or “mind-cure.”