How The Occult Thrived in an Age of Enlightenment

As the case of mesmerism showed, fighting fakery with facts is no match for the imagination

In 1778, the practice of animal magnetism started in Paris. Magnetists enjoyed six happy years; then a star-studded panel of mostly French academicians declared, as John Adams put it, that their science did not exist. Late in 1784, the American Herald published a letter from Adams, then in France, to his friend the physician Benjamin Waterhouse, then in Boston. The letter contained the first mention in the American press of both animal magnetism and its debunking at the hands of the French academicians. The Austrian physician Franz Anton Mesmer had been making a success de scandale in Paris by claiming to cure illnesses with the invisible fluid of “animal magnetism” (magnétisme animal), a living analog to mineral magnetism that was distributed throughout the cosmos and was especially active in human bodies. (“Animal” is something of a misnomer; Mesmer meant animal as opposed to mineral, not as opposed to human. Think “vital magnetism.”) Adams aptly called Mesmer’s practice “a kind of physical new light or witchcraft.” It mixed Bavarian exorcism, a practice Mesmer had claimed to explain with his own principles, with a view of matter that seemed vaguely drawn from Benjamin Franklin’s Experiments and Observations on Electricity (1751). According to Mesmer, imbalances in the magnetic fluid were at the root of all disease. By manipulating the fluid through gestures called the “magnetic passes,” he could make his patients seize, shriek, go into hysterics, vomit, and, allegedly, get well. The theory was that magnetization cleared obstructions in the movement of the body’s vital fluids. But Adams and other Anglophone observers were put more in mind of new-light Protestant convulsions in the Great Awakening. The prodigies of animal magnetism took place in Mesmer’s very public treatment salons, where the mise-en-scène showed the Austrian’s flair for theater. The walls were padded and decorated with celestial symbols, the air vibrated with glass harmonica music, and the doctor wore purple—flowing violet robes, to be exact. Some of the patients’ fits bore a suspicious resemblance to orgasm.

“The thing is so serious,” Adams told Waterhouse, “that the King has thought necessary to appoint a number of Physicians and Academicians, with your friend Franklin at their head, to enquire into it.” This, to Adams, was the point of the letter. Forget the pretensions of the “German Empirick” Mesmer; the real marvel here was Benjamin Franklin’s power of annihilation. Franklin was by this time in semiretirement in the Paris suburb of Passy. But he and the founder of modern chemistry, Antoine Lavoisier, cochaired one half of the dual investigating commission appointed by King Louis XVI to examine mesmerism. Franklin and his fellow commissioners had shown, Adams said, that “this Magnetism can never be useful, for the best of all possible reasons, viz.—because it does not exist.” Adams expected the commission’s report to “annihilate the enthusiasm” for Mesmer’s art. Franklin’s name became central to the American reception of the commissioners’ report. The Rapport des commissaires chargés par le roi de l’examen du magnétisme animal (1784), drafted by commission member Jean-Sylvain Bailly and translated by William Godwin as the Report of Dr. Benjamin Franklin, and Other Commissioners, Charged by the King of France with the Examination of the Animal Magnetism (1785), would find an interested audience in the United States even though mesmerism had never been practiced there. Magnetism slowly regained its footing in France after a brief intermission for the French Revolution; in the United States, by contrast, the successful introduction of the practice by Charles Poyen was still fifty years out. So it would be fair to say that animal magnetism came to the United States as a falsehood before it appeared there as a truth. In that intervening half century, magnetism was the quintessential example of modern idolatry. Guardians of public reason trotted out the 1784 report each time the crack-brained proponent of some new cure, prophecy, or electrical machine needed reminding of which side Franklin would have been on. As an exemplary falsehood, animal magnetism did a brisk trade.

Where does disenchantment actually put the things that do not exist; and what happens to them after that declaration? The 1784 commission report gives us a unique opportunity to ask those questions. It is a canonical instance of disenchantment. Faced with the claim that there existed something called “animal magnetism,” the commissioners showed that this alleged entity was a fetish, cobbled together out of a couple of natural causes and a good deal of credulity. Disenchantment stories like to end with broken idols. But as with many a conventional generic ending, the truth is more complicated. After the idols stop functioning, they resume their activity in a new way, often enjoying long and eventful second lives. That liveliness, I argue, takes place not in spite of disenchantment but in concert with it. The death knell the 1784 commissioners tried to ring was far less decisive than many observers had hoped it would be. Not only did the commissioners fail to obliterate animal magnetism—which, on the contrary, thrived throughout the first two-thirds of the nineteenth century—they also made a vital contribution to magnetism’s later theoretical apparatus. Later magnetists would incorporate some of the commission’s own anti-idolatry rhetoric, making the practice into a strange compound of the theories of its founder and of its first major debunkers. As for Poyen, the success of his 1836 lecture tour in the United States owed a debt to the Franklin commission. Poyen considered mesmerism a means of manipulating credulity, just as, in a different way, the commission had. Mesmerism’s long association with falsehood in the United States did not exactly hurt Poyen’s cause; he simply had to twist that association in another direction. Poyen and the other early mesmeric practitioners in the United States would till the rich fields of a half century of their own disrepute.


"The commissioners would ultimately claim not only that the patients’ credulity, aided by their imaginations, misled the patients about their own experiences, but that the experiences were, if you will, mis-had."


The commissioners who were appointed in 1784 had the puzzling task that disenchanters often face. Skeptical about the existence of the animal-magnetic fluid, they nonetheless found themselves confronted with magnetism’s alleged effects on patients’ bodies. If there was no such thing as animal magnetism, then whence the patients’ convulsions, vomiting fits, and so forth? Franklin and most of his colleagues attributed mesmerism’s remarkable effects to imagination, which was for them a mechanism by which belief could create physical symptoms in the body. If you believed in the efficacy of Mesmer’s proceedings, then you would for that very reason be excited and affected by them. Your belief, not the animal-magnetic fluid, would be the cause of your convulsions. Other factors mattered, too: gender, class, degree of education, and presence or absence of a mob of other sufferers. The commissioners would ultimately claim not only that the patients’ credulity, aided by their imaginations, misled the patients about their own experiences, but that the experiences were, if you will, mis-had. Imagination did not merely trick them into thinking they were feeling heat in a magnetized part of the body, or convulsing; it tricked them into actually feeling heat and convulsing. In other words, imagination made susceptible patients feel sensations and exhibit physical symptoms that had no other source beyond their thoughts. It was a robust machine for animating false idols and empowering nonexistent fluids. The two Paris commissions investigating mesmerism came from the academic institutions most directly threatened by Mesmer’s sensational cures: the Royal Society of Medicine and the Faculty of Medicine. To the Faculty of Medicine commission were also appointed six members of the Academy of Sciences, including the chairs Antoine Lavoisier and Benjamin Franklin and the eventual drafter of the report, astronomer Jean-Sylvain Bailly. The commissioners investigated the mesmerist Charles Deslon, one of Mesmer’s pupils, in spite of Mesmer’s protests that he ought to have taken center stage himself. Both commissions published their reports in August. Of the two reports, the Franklin–Lavoisier commission’s report was by far the more influential. It introduced the idea that imagination was responsible for the mesmeric effects, and it was also the report that Godwin chose to translate into English a few months later, with prefatory material including an original English introduction and a synopsis of M. A. Thouret’s Recherches et doutes sur le magnétisme animal (1784), a historical survey of magnetism-like phenomena before Mesmer. Throughout this book I refer to the Academy of Sciences–Faculty of Medicine report as the “Franklin report,” even though Bailly drafted it; the misnomer captures the way this document would be received among Anglophone readers, starting with Godwin’s free translation of the title: the Report of Dr. Benjamin Franklin.

The commissioners’ target was not animal magnetism alone; they took aim, rather, at the resurgence of superstitious practices in what were supposed to be enlightened times. Mesmer and Deslon’s public treatment salons struck the commissioners as a laboratory reproduction of darker ages, alarming but fascinating. Patients gathered around the baquet, a bucket filled with water and broken glass with iron bars protruding from it; they then applied the iron bars to the affected parts of their bodies. A rope bound the patients loosely to one another. Meanwhile Deslon’s assistants exerted pressure on patients’ stomachs and waved iron rods along the magnetic poles of their bodies. Music played in the background. Some patients felt nothing; others coughed or felt mild pains; but a third group were “agitated and tormented with convulsions . . . rendered extraordinary by their frequency, their violence, and their duration”; some also coughed up fluid. “Nothing can be more astonishing,” the commissioners acknowledged, “than the sight of these convulsions; he that has not had it, can have no idea of it.” It was hardly surprising that similar effects “seduced in former ages men, venerable for their merit, their illumination and even their genius, Paracelsus, Van Helmont and Kircher”—thus delaying the inevitable onset of enlightenment.  Even so, there was nothing in Mesmer’s claims; the magnetic effects were merely the products of imagination and fanaticism. Just as in “theatrical representation, where the impressions are greater in proportion to the number of the spectators,” and in military camps, “where the enthusiasm of courage, as well as the impressions of terror, are propagated with so amazing rapidity,” the movement of a convulsion passed from one patient to the next in the public treatment salons. The same contagion could account for religious exercises such as those of French Protestants known in the early eighteenth century for their spasmodic worship: “where fanaticism is the presiding quality, its fruit is the tremblers of the Cevennes.” Though presented as a newfangled science, “the magnetism then is no more than an old falsehood,” the commissioners would eventually conclude with a flourish.


"With habitual magnetization, imagination could not only stretch and distort the inner narrative. It could also create a repeatable process in the body that would seem to indicate the presence of an external object—animal magnetism—where none was"


The commissioners’ aim was not only to show that animal magnetism was false but also to show how it had appeared to be true. Thus they also needed an idol-function: something to substitute for animal magnetism in producing the patients’ physical exercises. Credulity played a key role. Early on, they hypothesized that magnetism existed only for the gullible: “the magnetism has seemed to have no existence for those subjects, who have submitted to it with any degree of incredulity [quelque incrédulité].” Working in private, away from the distractions of the public process, they had Deslon perform the magnetic gestures on a cross section of subjects: learned and ignorant, rich and poor, male and female. They even tested it on themselves. The results suggested that magnetism, much like tyranny and priestcraft, worked especially well on those who were poor, uneducated, or female, though for any of these groups, intelligence could serve as a safeguard. Against those who were “armed . . . with that philosophic doubt which ought always to accompany inquiry,” magnetism—much like enchantment—was powerless Just three patients exhibited effects that the commissioners could not explain away. These patients were all of “the lower class . . . while those of a more elevated rank, of more enlightened understandings, and better qualified to describe their sensations, have felt nothing.” The commissioners, on account of their “philosophic doubt . . . have felt none of those sensations.” Those who approached the magnetic process skeptically were, the commissioners maintained, unaffected, even if their nerves were susceptible. The well-heeled Madame de B—, for example, “felt nothing . . . she submitted to the magnetism with an extreme tranquility, which originated in the highest degree of incredulity [une grande incrédulité].”  Thus the rich and philosophical were immune to animal magnetism, while the poor and superstitious were vulnerable. It took some doing to impose this degree of order on the results. Actually, sensations during the process of magnetism were far from unique to the lower class; even among the commissioners there were several who felt “irritation of the nerves.” But the Report attributes these sensations to preexisting illnesses or to the effects of pressure on the stomach, whereas what the ignorant felt was to be attributed to their credulity. The commissioners expected to find superstition and dependence here, and so they knew they would find susceptible imaginations as well: “Let us represent to ourselves the situation of a person of the lower class, and of consequence ignorant,” proposed the commissioners, “attacked with a distemper and desirous of a cure, introduced with some degree of ceremony to a large company, partly composed of physicians, where an operation is performed upon him totally new, and from which he persuades himself before hand that he is about to experience prodigious effects.” Awed by the majesty of these physicians whose claims his education does not permit him to judge, this lower-class person is also “paid for his compliance,” and “he thinks he shall contribute more to our satisfaction by professing to experience sensations of some kind.” Here is a person who will unconsciously produce the sensations the doctors seem to require. The credulous person’s sensations when magnetized “were the fruits of  anticipated persuasion, and might be operated by the mere force of imagination.”

Imagination had a heavy explanatory load to bear. It had to produce not just mild physical sensations, but astonishing crises. It had to do all this, moreover, without its operations becoming evident to the subject, who had to mistake those operations for the effects of an external fluid, animal magnetism. Imagination had to be the equivalent of an inner mechanism for manufacturing idols, cobbling together convulsions, peculiar sensations, and strange prestidigitations into the single object “animal magnetism” as though they were so many feathers, carved wooden bits, and beads. There was reason to think imagination might be capable of such a feat. Imagination was the power of calling up objects that were not—and perhaps had never been—present to the senses. It allowed us, as Dugald Stewart explained in his Elements of the Philosophy of the Human Mind (1792), to “withdraw the attention at pleasure from objects of sense, and transport ourselves into a world of our own.” Nor was there anything out of the ordinary in the idea that the imagination could act on the body. This phenomenon had been observed in women whose unwholesome ideas during pregnancy engendered monstrous births. In the French tradition, as Jessica Riskin has pointed out, the trouble with imagination was primarily that while memory was “cool and calm,” imagination was “warm and vivid.”  Memory, too, called up objects not present to the senses, but imagination did so much more realistically. Thus it could, as Riskin puts it, “hijack the senses,” making one mistake inner vicissitudes for outer processes—exactly what happened to the mesmeric patients.

With habitual magnetization, imagination could not only stretch and distort the inner narrative. It could also create a repeatable process in the body that would seem to indicate the presence of an external object—animal magnetism—where none was. Stewart distinguished imagination from “conception” (a faculty closely related to memory) in that, rather than being confined to calling up an “exact transcript” of a past perception, imagination could “make a selection of qualities and of circumstances from a variety of different objects, and by combining and disposing these . . . form a new creation of its own.” In the case of habitual magnetization, imagination would aggregate effects that had initially come from pressure on the stomach or from the excitement of the public treatment salons: “The sensations having been felt once or oftener, nothing is now necessary, but to recal [sic] the memory of them, and to exalt the imagination to the same degree, in order to operate the same effects.” Thus while physical pressure and a crowd were necessary initially, later on, imagination alone could be enough.

Specifying the exact location of the body-mind nexus was an embarrassment, as it has ever been to those who attempt it; the commissioners hazarded that “the affections of the soul make their first corporeal impression upon the nervous centre” near the “diaphragm.” But if we grant the commissioners their equivalent to René Descartes’s pineal gland, then the important point becomes visible: imagination was a remarkable tool for the creator of newfangled idols. Imagination could concoct animal magnetism out of the effects of a number of causes and then replay the tapes “by its sole instrumentality.” The commissioners called animal magnetism “chimerical [chimérique],” and it was a “chimera” in the strict sense. The original chimera was a monster with a lion’s head, a goat’s body, and a serpent’s tail. From a disenchanting perspective, the chimera was a creature that did not exist, made out of the parts of creatures that did. So too was animal magnetism, according to the commissioners: it was a compound of imagination, imitation (at the public process), and touch. P. T. Barnum, the great humbugger, would later sew together a desiccated fish and a dried monkey and call it the Feejee Mermaid. Imagination did Mesmer’s sewing for him. It could in theory make a chimerical object on behalf of any charlatan who was capable of managing excitement and ginning up awe-inspiring proceedings—all without the subjects having any suspicion of what was happening under their skin.


Reprinted with permission from Credulity: A Cultural History of US Mesmerism, by Emily Ogden, published by the University of Chicago Press. © 2018 The University of Chicago. All rights reserved.

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