William James never had a mystical experience, and he said so. The man who wrote the most influential description of mysticism in the English language admitted, in the middle of the lecture, that his own constitution shut him out of such states almost entirely and that he could speak of them only at second hand.
That did not stop him. That may be why his account has lasted. It was written by an outsider with a scientist's patience, a novelist's ear for testimony, and one very odd afternoon with a bag of laughing gas.
Twenty lectures in Edinburgh
James (1842 to 1910) was a Harvard psychologist and philosopher. In 1901 and 1902 he delivered the Gifford Lectures on natural religion in Edinburgh, and published them in 1902 as The Varieties of Religious Experience, subtitled "A Study in Human Nature."
His method was unusual for a book about religion. He ignored churches, creeds and theology almost completely and went to the raw material: diaries, letters, confessions and case reports of what individual people said happened to them in solitude.
Lectures sixteen and seventeen are devoted to mysticism, which James treats as the root of personal religion. To use so slippery a word at all, he needed a working definition.
The four marks
James proposed four marks. If an experience has them, he said, it may reasonably be called mystical.
Ineffability. The experience defies expression. No adequate report of its contents can be given in words, so it has to be experienced directly, the way one has to have been in love or heard a symphony to know what either is like.
Noetic quality. This is the surprising one. Although the states resemble feelings, they seem to the people who have them to be states of knowledge, insights into depths of truth that ordinary reasoning cannot reach, and they carry a lasting sense of authority.
Transiency. They do not last. James thought half an hour, or at most an hour or two, was the usual limit before the state faded, though it could recur and deepen.
Passivity. The state may be invited by practice, but once it arrives the person feels their own will suspended, sometimes as if held by a superior power.
The list is short, memorable and deliberately neutral about cause. It describes what the experience is like, not where it comes from.
The laughing gas
James's one claim to firsthand knowledge came from chemistry. In 1874 an upstate New York farmer and amateur philosopher named Benjamin Paul Blood published a pamphlet called The Anaesthetic Revelation and the Gist of Philosophy, arguing that the moment of coming out of anesthesia disclosed the secret of existence. James reviewed it, unsigned, in the Atlantic Monthly that November. The review is skeptical but not contemptuous. He observed that the worst feature of any mystical knowledge is that it cannot be communicated, and that a thing which blunts the mind is a poor channel for truth.
Then he tried nitrous oxide himself. In 1882 he published what happened. Under the gas he felt an overwhelming sense of metaphysical illumination in which every opposition, sober and drunk, good and evil, seemed to dissolve into unity. It felt, he wrote, like what Hegel's philosophy must mean. He wrote sentences down as they came. Sober, he found them to be drivel, the tattered fragments of a revelation that would not survive daylight.
A lesser thinker would have filed that under "intoxication" and moved on. James kept both facts: the notes were nonsense, and the sense of insight was real as an experience. Twenty years later, in the Edinburgh lectures, he was still chewing on it. He allowed himself an aphorism about alcohol: "Sobriety diminishes, discriminates and says no; drunkenness expands, unites, and says yes." And he drew the conclusion for which the book is best remembered, that normal waking consciousness is only one type, and that other forms lie all around it, "parted from it by the filmiest of screens."
James was reporting an experiment, not recommending one, and his verdict on its contents stayed mixed. What it gave him was a principle: no account of the universe is complete if it leaves these other states out.
What authority do they have?
James ended the lectures with a three-part ruling that is still a decent guide. First, mystical states are, as a matter of psychological fact, authoritative for the people who have them. Second, they carry no authority for anyone else: outsiders have no duty to accept the revelations, especially since mystics from different traditions report incompatible things. Third, their mere existence breaks the monopoly of the rational, everyday mind as the only judge of what is real.
He would not call the mystics deluded, and would not call them right.
From the lecture hall to the lab
The four marks did not stay in philosophy. In 1960 the philosopher W. T. Stace, drawing on James, surveyed mystical reports across religions and distilled a set of common features. Two years later Walter Pahnke used Stace's work to score his Good Friday experiment, in which theology students in Boston were given psilocybin on Good Friday. His nine categories included ineffability, noetic quality and transiency, three of James's four, under nearly the same names.
Pahnke's questionnaire was revised over the following decades into the Mystical Experience Questionnaire, used in the Johns Hopkins psilocybin studies that began appearing in 2006. A 2015 validation study of the current 30-item version cites James in its opening lines and reports four factors, one of which is ineffability, with noetic quality folded into a factor labeled "mystical." Ralph Hood's Mysticism Scale, developed in the 1970s for the psychology of religion, descends from the same source. Passivity, tellingly, never got a scale of its own, and transiency was dropped along the way.
Not everyone thinks this inheritance is healthy. A 2021 paper in a pharmacology journal argued that the mysticism framework smuggles supernatural overtones into science and should be replaced with plainer cognitive models. There is also an obvious circularity risk: a questionnaire built from a definition tends to find what the definition describes.
A definition that outlived its author
James would probably have enjoyed the argument. His four marks were offered as a convenience, a way to get on with the lecture, and he was frank that the boundaries were fuzzy. More than a century later they are printed on clinical forms.
The real legacy is the stance behind the list: take the reports seriously as data, describe them carefully, and decline to decide in advance what they prove. He managed it without ever having the experience himself.