What counts as "serious science" and what as superstition or fraud usually seems to us a fixed fact. The history of hypnosis shows how movable that line really is. The same phenomenon – a person in an altered, suggestible state – was publicly dismissed as imagination in 1784 by a Paris commission under Benjamin Franklin and Antoine Lavoisier. It took more than two hundred years for it to be fully accepted as science – and in the end what tipped the balance was not a better argument but a new device: the brain scan, which made the effect of suggestion visible. It was not the phenomena that had changed, but their classification.
Mesmer and "animal magnetism"
The German physician Franz Anton Mesmer (1734–1815) claimed that a fine, invisible fluid pervaded the whole cosmos and the human body; illness was a disturbance in its flow, healing the restoration of balance through "animal magnetism". From 1778 he became a sensation in Paris. His patients sat around a baquet, a tub filled with "magnetised" water, grasped iron rods and often fell into violent "crises" – convulsions, laughter, tears – after which they felt improved. The sessions were staged for effect: dimmed light, mirrors and the glassy tones of a glass armonica, which Mesmer – an acquaintance of Mozart – played himself. The rush was so great that Mesmer "magnetised" whole trees so that more people could be treated at once.
The 1784 verdict: "imagination"
In 1784 King Louis XVI appointed two royal commissions. The most important, formed by the Academy of Sciences, was high-powered: alongside the American envoy Benjamin Franklin, the chemist Antoine Lavoisier, the astronomer Jean Sylvain Bailly and the physician Joseph-Ignace Guillotin. Their procedure was groundbreaking for the time: they did not assess Mesmer's theory, they tested it. In experiments that count among the first blinded trials in history, they led subjects to believe they were being magnetised when they were not – and vice versa. The result was unambiguous: the effect appeared when the person expected it, not when "magnetism" was applied.
On 11 August 1784 the commissioners declared animal magnetism an imagination without real basis; no magnetic fluid existed, the effects came from "imagination". On the substance they were right – there is no such fluid, and their method was a milestone, in effect the birth of the controlled trial and of the placebo concept.
What the commission threw out with it
Yet in that same year, 1784, one of Mesmer's pupils, the Marquis de Puységur, stumbled on something the commission had not in view. Instead of the wild crises he produced in his servant Victor a calm, sleep-like state in which the man remained responsive, followed instructions and afterwards remembered nothing – "artificial somnambulism", the trance proper. Here lay a real phenomenon: the power of expectation and suggestion over body and mind. By dismissing the non-existent fluid, the public dismissed the whole field with it – and the genuine phenomenon vanished from serious research for decades. The commission had judged the physics correctly and pushed a psychological fact aside in the process.
The "higher phenomena" – and the road to spiritualism
The matter is complicated further by the fact that the somnambules were soon credited with far bolder abilities: clairvoyance, "seeing" illnesses in their own body or in others, even perception at a distance. This strand tied mesmerism closely to the supernatural and fed, in the 19th century, into modern spiritualism. Important for an honest account: this part was never rehabilitated. The trance and suggestion became science; the clairvoyant claims remained unproven and belong, to this day, to the contested area this site treats elsewhere (physical mediumship).
James Braid (1843): magnetism becomes hypnosis
The decisive step toward respectability was taken by the Scottish surgeon James Braid. In his book Neurypnology (1843) he coined the words "hypnotism", "hypnosis" and "to hypnotise". That was more than renaming: Braid discarded the fluid entirely and explained the state physiologically and psychologically – as a result of fixed attention, a property of the patient's nervous system, not a force of the operator. With the loaded word "magnetism" the bad reputation fell away too. The same phenomenon, freshly described, became discussable. Braid himself later noticed that his hypnotised subjects were not actually asleep and considered renaming the state "monoideism" (domination by a single idea) – but the catchy word "hypnosis" could no longer be recalled.
Charcot and the return to the academy (1882)
A first academic return came through Jean-Martin Charcot, the most famous neurologist of his day, at the Paris Salpêtrière. In 1882 he presented his work on hypnosis to the Académie des sciences – of all bodies, the one that had dismissed animal magnetism in 1784. This time he was heard. The irony is complete: the same academy, almost a hundred years later, brought the disreputable subject back into the lecture hall. Charcot's own reading – that hypnosis was a pathological state, possible only in hysterics – later proved wrong. But it lent the subject the necessary seriousness. In Charcot's lecture hall in 1885/86 sat a young Viennese doctor too: Sigmund Freud, who began with hypnosis before replacing it with free association.
Nancy versus Paris: suggestion wins
Against Charcot's pathology thesis the Nancy school prevailed – Ambroise-Auguste Liébeault and Hippolyte Bernheim. Their thesis: hypnosis is nothing pathological but rests on suggestion, a normal property of every human being. With that Nancy picked up again the thread the commission had begun in 1784 with the word "imagination": what was recognised as effective was the power of expectation. From this line descend directly modern suggestion research and what we now call the placebo effect and psychosomatics.
And yet: another century of doubt – until the brain scan
As clean as that line sounds, the acceptance of hypnosis itself was not so smooth. Throughout the 20th century it remained marginal in academic medicine and suspect to many – too close to the stage trick and the fairground. In psychology the counter-thesis even prevailed for a time: that hypnosis is no distinct state of consciousness at all but mere role-play, expectation and social compliance (so Theodore Sarbin in the 1950s, Theodore Barber and Nicholas Spanos from the 1970s). Anyone appearing "hypnotised", on this view, was really just highly motivated to play the part.
What tipped the balance was a new instrument: brain imaging. In 1997 Pierre Rainville and colleagues showed, using positron-emission tomography, that hypnotic suggestion selectively alters the unpleasantness of pain – measurably, in the region responsible for it (the anterior cingulate cortex), while the processing of raw stimulus intensity was left untouched. Later fMRI studies confirmed throughout: what the subject reports under suggestion shows up in the activity of exactly the relevant brain regions. With that the old objection "mere compliance" was defused – not by a new argument, but by a device that did not exist in 1882. The full acceptance of hypnosis is thus not a matter of the 19th century but of the late 20th.
Alongside this long struggle for scientific recognition, hypnosis had long since reinvented itself in clinical practice. The American psychiatrist Milton H. Erickson (1901–1980), founding president of the American Society of Clinical Hypnosis (1957), broke with the authoritarian commands of the 19th century ("You are getting sleepy!") and worked instead with indirect suggestions, stories and metaphors that bypass the critical mind rather than overrun it – the foundation of modern hypnotherapy. Today hypnosis is an established clinical tool: at the university hospital in Liège the anaesthetist Marie-Élisabeth Faymonville has, since the 1990s, performed several thousand operations under "hypnosedation" – conscious patients, local anaesthesia and a fraction of the drugs otherwise needed; it also belongs today to the recognised repertoire for irritable bowel syndrome, anxiety and pain.
What this says about the boundary of "science"
The lesson is not that "the sceptics are always wrong" – the 1784 commission was right about the fluid, and the clairvoyant claims remain unproven to this day. The lesson is subtler and more uncomfortable: the line between science and superstition is not a law of nature but is drawn by institutions at a particular time – and it moves. One and the same phenomenon lay once beyond, once within the line. Science absorbed what it could naturalise (trance, suggestion, placebo) and left out what did not fit (fluid, clairvoyance). That is legitimate – but it also means that today's classification of other phenomena need not be the last word.
That is exactly the thread of this site. How hard the scientific establishment finds uncomfortable findings is treated in the articles on physical mediumship and on hidden knowledge and power logic. That one and the same person could work on this moving boundary is shown by the portrait of Albert von Schrenck-Notzing, who came from hypnosis and suggestion research and then turned to mediumship research.
Sources:
• Report of the commissioners charged by the king with the examination of animal magnetism (the Franklin/Bailly commission), Paris 1784.
• James Braid, Neurypnology; or, The Rationale of Nervous Sleep, London 1843.
• Hippolyte Bernheim, De la suggestion, Paris 1884.
• Henri F. Ellenberger, The Discovery of the Unconscious, 1970.
• Adam Crabtree, From Mesmer to Freud, 1993.
• Pierre Rainville et al., Pain affect encoded in human anterior cingulate but not somatosensory cortex, Science 277 (1997).
• Jay Haley (ed.), Advanced Techniques of Hypnosis and Therapy: Selected Papers of Milton H. Erickson, 1967; Marie-Élisabeth Faymonville et al., clinical studies on hypnosedation, CHU de Liège.
For more, see our curated knowledge collection and the series on the history and science of mediumship.