It was in a mood of irritable skepticism that the Scottish surgeon James Braid attended a public demonstration of Animal Magnetism—in which people were said to fall into trances—on the night of November 13, 1841. From everything he had read and heard about the trances that occurred at the bidding of the operator—the person who induced the trances—he reports that he was “fully inclined to join with those who considered the whole thing to be a system of collusion and delusion, or an excited imagination, sympathy, or imitation.” After observing the demonstration, he considered that the trances were quite genuine, but at the same time he felt satisfied “that they were not dependent on any special agency or emanation passing from the body of the operator to that of the patient as animal magnetizers allege.” He returned to the demonstration when it was repeated by popular demand a week later, and on this occasion he felt that he had identified the cause of these mysteriously punctual onsets of “nervous sleep.” He was to devote the last eighteen years of his life to the topic, and under the proprietary title of Hypnotism he explained and redescribed the process in terms which would have been unrecognizable to its eighteenth-century discoverer, Franz Anton Mesmer.

Franz Anton Mesmer
Franz Anton Mesmer; drawing by David Levine

Mesmer was born in the lakeside town of Constanz in 1734, and after receiving a philosophical education from the local Jesuits he studied medicine at the University of Vienna and qualified as a physician in 1767 with the publication of an MD thesis on the influence of celestial gravity on human physiology. He argued that the rotation of the heavenly bodies exerted gravitational influence on human physiology analogous to the tidal effect of the moon upon the ocean and that this accounted for the periodic incidence of various diseases.

To explain the transmission of this influence he invoked the existence of an immaterial substance, a weightless or so-called imponderable fluid, whose universal distribution guaranteed action at a distance. The notion of such an ethereal medium can be traced back to Greek antiquity and under various titles—ether, spiritus, pneuma, etc.—it figures as a recurrent theme in European scientific thought. It played a prominent part in the long tradition of Neoplatonism, and in all probability it was under the influence of this somewhat occult tradition that Isaac Newton cautiously invoked the existence of “a subtle spirit which pervades and lies hid in all gross bodies; by the force and action of which spirit, particles of bodies attract one another.” The medium is frequently mentioned in Newtonian unpublished correspondence, and there are several references to it both in the Principia and in the more widely read Optics.

Although Newton stressed it was no more than a hypothesis, some of the commentators who sought to explain and publicize his work appear to have taken the existence of the Newtonian ether quite literally, insisting that it was the only intelligible explanation for the distant transmission of gravity, light, heat, and magnetism. It was evidently from one of these secondary sources that Mesmer derived the concept of an imponderable fluid and then applied it uncritically to the questionable effect of gravity upon human physiology.

For obvious reasons Mesmer did not foresee any remedial implications of his theory, but on learning that a Jesuit astronomer had conducted successful clinical experiments with magnets, he decided to follow suit, recognizing an affinity between gravity and magnetism. By drawing powerful magnets over the limbs of patients afflicted with a variety of disabling conditions, Mesmer believed that he was wielding a local influence comparable to that of celestial gravity and that the effect was mediated by the ethereal substance which he had mentioned in his MD thesis.

In the ensuing squabble over priority, Mesmer abandoned the magnetic technique for which he would have had to share the credit, and since he was eager to establish an exclusive claim, he announced that he had identified a previously unrecognized form of magnetism whose application for medical purposes did not require the disputed use of ferrous metals. According to him, the human nervous system was charged with “animal” magnetism—so-called because it was associated with the soul or anima—and although it was not physically detectable he insisted that it could be mobilized by the will of an initiated practitioner and broadcast to living bodies in the vicinity.

He administered the treatment by passing his hands up and down the length of the patient’s body without actually touching the surface. In a series of conspicuously uncontrolled trials he reported dramatic improvements, noting that the most favorable outcome was obtained when the patient reacted to the “magnetic” passes by falling into a convulsive trance. In fact, the fits and trances began to assume an emblematic importance and among a significant proportion of his clientele they were valued just as much as the medical relief.


The combination of unorthodox procedures on the part of the practitioner and the frequently unseemly behavior on the part of the patient predictably aroused the suspicion of Mesmer’s professional colleagues in Vienna, and in 1778 he felt obliged to emigrate to Parts. In a metropolitan city in which the educated public was almost frivolously susceptible to scientific novelty, a medical treatment based on a previously unacknowledged force of nature proved irresistibly attractive; and since the orthodox profession tormented its clients with ineffectual purges and emetics, the arrival of animal magnetism was heralded as a medical millennium. In any case, the trances and “fits” alone were worth the price of admission, and for many of the clients who attended as spectators the magnetic “crises” were the main attraction.

Once again, the incontinent festivities became a subject of scandalous controversy, and in 1785 two official commissions were appointed to investigate the matter. Both of them reported unfavorably, but from the scientific point of view the most damaging conclusions were the ones published under the auspices of a commission appointed by the Academy of Sciences. The commission, which included Benjamin Franklin and Lavoisier, insisted that neither the trances nor the cures had anything to do with magnetism but depended on what would now be called the placebo effect, that is to say, upon the patient’s powerful expectation of the forecast result. If the “magnetic” procedure was inaudibly performed behind a magnetically transparent screen, so that the patient was unaware of it, nothing happened, proving that the mesmeric enterprise depended upon the patient’s susceptible imagination and not, as Mesmer argued, upon a peculiar form of magnetism emanating from the operator.

It was not the first time that “imagination” had been invoked to explain anomalous medical phenomena. By the end of the eighteenth century there was a large body of specialist literature devoted to the physiological influence of the mind upon the body, and although the term “imagination” suggests to the modern reader that the effects were visualized as being unreal or imaginary, for the eighteenth-century theorist it implied that the effects, real enough in themselves, were caused by the imagination. How they were caused remained a mystery, and to that extent the theory of the imagination is scarcely a theory at all. Nevertheless, it had the advantage of being considerably less implausible than the theory of animal magnetism, and for that reason “imagination” was repeatedly cited by scientists and physicians, who found the rigmarole of imponderable fluids and magnetic emanations philosophically unacceptable.*

Another reason for favoring the otherwise inconclusive theory of the imagination is that by putting the emphasis on the patient’s susceptibility it diminished the vainglorious pretensions of the mesmerists and of Mesmer in particular. Although he advertised animal magnetism as a natural function and implied that its remedial potential could be realized by anyone who took the trouble to master it, as time went on his behavior gave a different impression altogether. He jealously guarded the details of his technique, and from his dress and his demeanor in the magnetic salon it seems clear that he was happy to project the image of a magus. Clothed in a robe embroidered with Rosicrucian alchemical symbols, he stalked the darkened rooms to the accompaniment of a glass harmonica and actively encouraged his clients to luxuriate in their convulsive crises. By 1785 the whole enterprise had become melodramatically inconsistent with scientific professionalism, and the scientific establishment did what it could to close him down.

Although Mesmer’s personal reputation suffered irreversibly as a result of these criticisms, the cult of animal magnetism was, if anything, encouraged by the controversy, and throughout Europe it continued to attract clients precisely because it was the subject of official criticism. In fact, it was visualized in its own time in much the same way as unorthodox or fringe remedies are today, i.e., as part of a subversive counterculture.

A few months after the publication of the French reports, paragraphs appeared in the London press advertising introductory lectures and demonstrations of the “new method for healing all known diseases,” and by 1786 mesmerism was flourishing in the hands of local practitioners, of whom at least two claimed to have learned the technique from Mesmer himself.

Although it was advertised as a remedial treatment, the clientele was by no means confined to the sick and disabled. On the contrary, many of those who attended the séances were attracted by the metaphysical implications of the doctrine, by what M. H. Abrams called its “natural supernaturalism.” With its intriguing combination of occult powers, clairvoyant trances, and invisible weightless fluids, animal magnetism seemed to guarantee the existence of a reality beyond the world of the senses, and many people saw it as an irresistible alternative to an increasingly mechanized picture of the universe.


Political events on the other side of the English Channel soon cast a shadow of official suspicion over anything associated with France, and since animal magnetism had an additional ingredient of subversive radicalism it rapidly lost its following and by 1794 it more or less vanished from the English scene.

The interest was dormant rather than dead, however, because the arrival of a visiting French magnetist—Baron Dupotet—in 1836 set off one of the most controversial episodes in the history of the subject, incidentally wrecking the academic career of one of London’s most distinguished physicians.

Shortly before the arrival of the mesmeric Baron Dupotet, John Elliotson, a close friend of Dickens, Thackeray, and Wilkie Collins, had been appointed to the Chair of Medicine at University College, London. Apart from his distinguished contributions to clinical medicine, he was widely regarded as one of the more “philosophical” members of the profession, and in his preoccupation with some of the larger issues of Life and Mind, he often dismayed his colleagues by sponsoring unorthodox causes. For example, he was president and founder of the London Phrenological Society, and since there seemed to be an elective affinity between phrenology and animal magnetism, Elliotson greeted the visiting mesmerist as a kindred spirit. After witnessing his first public lecture he invited him to conduct further demonstrations in his own wards at University College.

It is difficult to imagine a more inappropriate setting for such an experiment. The public wards of a nineteenth-century charity hospital were filled with impressionably dependent patients, and since Elliotson failed to observe any of the precautions taken by the French commissioners forty years earlier, the misleadingly favorable outcome was a foregone conclusion. Confronted by two impressive practitioners, neither of whom could presumably disguise their coercive optimism, the patients dutifully, albeit unconsciously, enacted what was expected of them and the familiar pantomime of trances, fits, and “cures” duly ensued. And since the behavior of any one subject was unavoidably witnessed by all the others in the ward, the remedial influence of the “imagination” grew by geometric progression, thereby guaranteeing unanimous therapeutic success. By the time the itinerant visitor had taken his departure Elliotson had become an evangelical convert to animal magnetism, and in the hospital wards under his jurisdiction an unruly atmosphere of mesmeric revivalism prevailed. By now he had identified a group of patients whose susceptibility was such that they could be relied on to produce dramatic evidence in favor of the new treatment, and before long Elliotson was advertising public demonstrations in the lecture theater at the hospital.

Two women—the Okey sisters—emerged as the stars of this mesmeric cabaret, and in the course of the next few years they acquired a legendary reputation as spectacular trance subjects. By all accounts they seem to have been convulsive hysterics, and although they were admitted to the hospital under that label they had unconsciously exploited the same symptoms in a different institution altogether. In his medical memoirs the then assistant editor of The Lancet reported that the sisters had already achieved considerable notoriety in a Pentecostal congregation in a nearby church, where their glossolalic interventions had attracted admiring attention. The career of these two young women neatly illustrates the way in which the symptoms of serious personality disorders can be shaped and then reshaped, depending on the social institution in which they manifest themselves. In a congregation that recognized and valued the notion of “speaking in tongues” the sisters modulated their conduct until they were recognizable as Pentecostal prophets, whereas in the wards of the newly converted professor of medicine their repertoire changed under the influence of Elliotson’s positive conditioning and they re-emerged as mesmeric shamans.

The scandalous high jinks had by now reached the point where the College Council could no longer ignore them and Elliotson was firmly requested to cease these unseemly demonstrations. He indignantly refused, claiming that he and Mesmer had identified a new force in nature and that by demonstrating its influence to the educated public he was offering an opportunity to exploit a mighty engine for the regeneration of humanity “comparable in importance and power to that of the steam engine.” The authorities, however, were adamant and Elliotson resigned in a high dudgeon. He continued to have a successful private practice, however, and since he was no longer tied down by the bureaucratic constraints of the university, he maintained a magnetic practice in parallel to one of conventional medicine. A few years after his resignation he inaugurated, edited, and was one of the leading contributors to a journal entitled The Zoist, devoted to the twin topics of phrenology and mesmerism. Naturally, much of the editorial matter was taken up with reports of successful magnetic treatments together with phrenological accounts of notable crania. The journal, however, was characterized by a conspicuous commitment to liberal causes—penal reform, the abolition of capital punishment, the education of workingmen, etc.

Although he was robbed of his prestigious chair, Elliotson continued to enjoy a prosperous professional life with a wide circle of admiring and affectionate friends. Until the early 1850s his name was almost synonymous with that of British mesmerism, and throughout his active life he continued to sponsor the original “magnetic” interpretation of the phenomena.


By the time James Braid began his inquiries in Manchester in the early 1840s there was an effective stalemate between those who sponsored the magnetic fluid and skeptics who preferred to explain the phenomena in terms of the patient’s susceptible imagination.

As a result of the observations which he made on the occasion of his second visit to the demonstration of animal magnetism, in 1841, Braid effectively broke the deadlock, since he was able for the first time to interpret the subject’s contribution in a somewhat more intelligible way.

Braid noticed that the entranced subject was invariably unable to open his eyes, which led him to the belief that the trance was induced by something which he described as the neuromuscular exhaustion induced by the protracted stare encouraged by the operator. To confirm this hunch he invited a friend at home later to gaze unblinkingly at the top of a wine bottle, as he said, “so much above him as to produce a considerable strain on the oculomotor muscles.” He described the results in the following words:

In three minutes his eyelids closed, his head drooped, his face was slightly convulsed. He gave a groan and instantly fell into a profound sleep, the respiration becoming slow, deep and stertorous. At the same time his right hand and arm were agitated by slight convulsive movements.

He repeated these experiments on his wife and on his manservant, and having obtained the same results on each occasion, he was convinced that he had efficiently demystified the mesmeric process. He already knew that it had nothing whatever to do with magnetism and the explanation he provided was considerably more specific than the traditional theory of the imagination. All the phenomena, he insisted, were to be explained as the neurological consequences of “a fixed stare, absolute repose of the body, fixed attention, and a suppressed respiration concomitant with that fixity of attention.”

By formulating the concept of “nervous sleep,” or hypnotism, Braid dealt a death blow to the pseudoscientific theory of animal magnetism and at the same time supplied a more convincing alternative theory. Nevertheless, it is easy to overestimate his intellectual achievement, or to put it more accurately, it is easy to underestimate the extent to which Braid was disabled by his own prejudices. The problem is that when someone coins a term by which a concept is currently known, it is tempting to imagine that his sense of the term corresponds to our own and that, like a Yankee at the court of King Arthur, Braid was a modern psychologist living unrecognized before his time.

The truth of the matter is that although he rendered an important service by stressing the condition of the patient’s nervous system as opposed to supernatural power on the part of the practitioner, in almost every respect he turns out to have been just as credulous as the mesmerists that he criticized.

For example, as soon as he discovered how easy it was to induce the hypnotic trance by fixed attention, looking at bottle tops and so forth, he visualized almost unlimited prospects of therapeutic effectiveness. Nearly two thirds of the first book which earned him his fame is taken up with implausible accounts of dramatic cures achieved under the influence of “nervous sleep.”

The skepticism with which he originally approached the subject seems to have gone out of the window. Here he records his experience with a congenitally deaf patient:

Hitherto, these patients have been considered beyond the pale of human aid. The morbid condition of the organs as ascertained by dissection was sufficient to warrant the inference that it was improbably that any remedy could be discovered for such cases.

Fully aware of this pathological difficulty I was nevertheless inclined to try the effect of neurohypnotism with congenital deaf mutes, knowing that it could be done with perfect safety, without pain or inconvenience to the patients.

From having witnessed its extraordinary power of arousing the excitability of the auditory nerve, I entertained the hope that it might be capable of exciting some degree of hearing from the increased sensibility of the nerves compensating for the physical imperfection of the organ. The result of my first trial was beyond my most sanguine expectations which induced me to persevere and the result has been that I have scarcely met with a single case of the congenitally deaf mute where I have not succeeded in making the patient hear to some degree.

With undiscriminating enthusiasm, Braid records more than fifty cases, ranging from hemiplegias, spinal curvatures, to ankylosing spondylitis and epilepsy, and in almost every instance, he reports conspicuous improvement. Even the most ardent supporter of hypnotism would find it hard to identify with Braid’s claims.

In fact, as one reads on, it begins to look as if the imagination of the physician is just as relevant to the outcome. Certainly this seems the case when it comes to some of the other phenomena which hypnotism supposedly brought to light. Braid, it seems, like his colleague Elliotson in London, was an ardent phrenologist. And as soon as he learned to control the hypnotic condition, he was exploiting it to prove the existence of the cerebral organs which had previously been identified by Gall and Spurzheim.

By touching the hypnotized patient at various points on her skull, he was gratified to witness behavior that corresponded to the function of the organ which supposedly lay beneath the magnetizer’s finger.

Miss S, who knew nothing of either hypnotism or phrenology, sat down and in a few minutes she was not only decidedly hypnotized, but was also one of the most beautiful examples of the phrenological sway during hypnotism.

The moment the organ of veneration was touched, her features assumed the peculiar expression of that feeling. Her hands were clasped. She sank on her knees in the attitude of pious adoration. When the organ of hope was touched in addition, the features were illuminated and she beamed with a feeling of ecstasy. On changing the points of contact to the organ of Firmness, she instantly arose and stood in an attitude of defiance.

A touch on the organ of self esteem and she flounced about the room with the utmost self importance. Under Acquisitiveness, she stole unashamedly, and yet when Conscientiousness was stimulated, she instantly restored the stolen property.

Her philoprogenitiveness was admirable.

And so on, page after page. The results are so bizarre and so self-evidently questionable that one is struck by the disproportionate pedantry with which Braid sought neurological explanations for what had occurred.

He recognized, for example, that the scalp was innervated—i.e., anatomically supplied—by the fifth cranial nerve, and conceded that none of its fibers passed directly through the skull to the brain beneath. Nevertheless according to him, there was every reason to believe

that the distribution of the nerves of the scalp will be ultimately found far more intricate and beautifully arranged than at present we have conception of. And that the cerebral extremity of each fiber will be found to be connected with the peripheral extremities of a single fiber only. And that this peripheral extremity is in relation with only one point in the brain or spinal cord.

Ingenious though this baroque scheme. is—and one might want to say it foreshadows modern concepts of mapping the body surface onto the cerebral convolutions of the brain—it is absolutely absurd as an explanation of the improbable behavior cited by Braid.

And yet, as it happens, at least two of Braid’s contemporaries spotted something indispensably valuable in all this phrenohypnotic tomfoolery. But what they saw had nothing to do with either phrenology or with remedy.

Braid’s “hypnosis,” now stripped of its magnetic pretensions, seems to have revealed to these observers something interesting about the functions of the nervous system. Something for which there was plenty of anecdotal evidence but, as yet, no repeatably experimental facts.

Benjamin Carpenter, one of the most distinguished physiologists of the nineteenth century—a professor at University College in London—insisted that Braid’s research had indeed thrown more light on what he, Carpenter, described as the reflex functions of the brain than any other investigations hitherto. So also did Thomas Laycock, professor of medicine at Edinburgh and the teacher of the neurologist John Hughlings Jackson at York—although Laycock was somewhat more preoccupied with proving that it was he and not Carpenter who first recognized the existence of reflex action above the spinal cord.


But what did both these men mean when they referred to the reflex function of the brain, and how had Braid’s work helped to elucidate it? What they were referring to is that vaguely defined area of both action and cognition which lies between the unarguably automatic and the selfevidently voluntary. Or to put it another way, between actions of which the individual has no conscious control, and actions and cognitive processes for which the existence of consciousness is absolutely essential.

At the same time it was generally recognized, and not only by physiologists, that between these two apparently distinct provinces of human behavior, there was a broad strip of territory in which it was not all that easy to determine the exact identity of the behavior or the cognition in question. For example, we all know that when the ground underfoot is treacherous and uncertain, we have to devote all our attention to the act of walking. And yet when the going is good and our attention is diverted by an interesting conversation, we can stroll along, confident that the strides will take care of themselves. Learning to play a piece of music will monopolize all our attention while we’re learning, but once we’ve mastered the fingering, we are capable of playing the melody and devoting our thoughts elsewhere—perhaps to imagining how large a fee we can demand for the performance.

The same principle applies to perception. We all know that heedlessness is more apparent than real and that as long as we are prompted or “cued” in the right way, we’re often surprised to recall seeing something while our attention was apparently elsewhere. Everyone knows the experience, the alarming experience, of arriving home with a problem on his mind, not having remembered a single episode on the journey until reminded of it. Laycock and Carpenter gave special emphasis to involuntary memory, the well-known experience of effortlessly recalling a forgotten name after hours spent strenuously trying to remember it. And Carpenter records in his books many examples of solving intractable problems just by sleeping on them. Laycock and Carpenter insisted that these facts revealed something fundamental about the way in which mental activity was organized. Both men quote the same passage from the philosopher Sir William Hamilton in support of this claim. This is what Hamilton wrote in 1842:

What we are conscious of is constructed out of what we are not conscious of. Our whole knowledge in fact is made up of the unknown and of the incognizable. There are many things which we neither know nor can know in themselves, but which manifest themselves indirectly through the medium of their cognitive effects. We are thus constrained to admit, as modifications of mind, what are not phenomena of consciousness.

Far from claiming any originality for this insight, Sir William Hamilton argued that the credit was largely due to Leibniz, while indicating at the same time that Leibniz had been unfortunate in the terms that he employed to propound his doctrine. By using such terms as obscure representations, “insensible ideas,” or “petites perceptions,” Leibniz was, according to Hamilton, violating the universal characteristics of language. “For perception, idea and representation,” he said, “all properly involve the notion of consciousness.” Not necessarily, argued John Stuart Mill. In his Examination of Sir William Hamilton’s Philosophy, he pointed out that there was another way of resolving this apparent contradiction. Mill writes:

If we admit what physiology is rendering more and more probable, that our mental feelings as well as our sensations, have for their physical antecedents, particular states of our nerves, it may well be believed that the apparently suppressed links in a chain of associations, really are so. So that they are not even momentarily felt. The chain of causation being continued only physically by one organic state of the nerves succeeding so rapidly, that the state of consciousness appropriate to each is not produced.

I’m not suggesting that either Laycock or Carpenter was directly inspired by either Hamilton or Mill, though each quotes both philosophers. But I think that Hamilton and Mill encouraged Laycock and Carpenter to press for the recognition of a cerebral process analogous to the automatic reflexes of the spinal cord. Carpenter called it Unconscious Cerebration, whereas Laycock stuck to the phrase with which he claimed to have originated the idea, i.e., “reflex function of the brain.”

The reason both Carpenter and Laycock stress the importance of Braid’s work, notwithstanding its phrenological excesses, is that the hypnotic trance, as they saw it, exposed the action of these unconscious processes. By artificially paralyzing the will, a broad layer of automatic action was now made conveniently visible, or so they claimed.

The truth is that it’s hard to tell just how much Braid’s contribution weighed in the final outcome. Laycock had published his first intimations on the subject of the reflex functions of the brain a year before Braid witnessed the magnetic exhibition in Manchester. And although Carpenter refers with increasing frequency to the significance of hypnosis in the subsequent editions of his General Physiology, there were preexisting reasons for believing that the neurological function of the brain was not confined to either consciousness or voluntary action, and that in spite of all superficial appearances to the contrary it retained a large repertoire of automatic actions.

The most persuasive argument in favor of this idea was one to which Thomas Laycock had been exposed during his student years in Germany. In subsequent publications he acknowledged the influence of a group of theoretical biologists known as Naturphilosophes who insisted that the design of the vertebrate nervous system was inherited from an ancestral prototype in which a set of homologous modules was arranged in a linear series from one end of the body to the other. According to the theory, the central nervous system of this admittedly hypothetical ancestor consisted of a sequence of identical segments, and there was, as yet, no visible distinction between the segments at the front end of the body and those at the rear. But with the development of senses specialized to detect distant events—eyes, ears, and olfactory organs—a process called cephalization began to set in and a recognizable head started to make its appearance. The first ten segments of the central nervous system then enlarged and coalesced to form a brain, distinguishable from the spinal cord which retained the ancestral pattern of serial segmentation. According to the theory, neurological function was correspondingly differentiated. The spinal cord continued to execute automatic reflexes in response to local stimuli, while the brain, now in receipt of information about more remote events, assumed overall control and acted as a command module.

But although the brain increasingly undertook the responsibility for more thoughtful behavior, the fact that it was derived from neural segments or ganglia which were once indistinguishable from the ones that composed the spinal cord meant that it preserved a discoverable repertoire of automatic actions. It was under the influence of this theory that Laycock addressed the York meeting of the British Association for the Advancement of Science in 1844.

Four years have lapsed since I published the opinion that the brain, although the organ of consciousness, is subject to the laws of reflex action. I was led to this opinion by the general principle that the ganglia within the cranium, being a continuation of the spinal cord, must necessarily be regulated as to their reaction to extended agencies by laws identical to those which govern spinal ganglia and their analogues in lower animals.

A careful reading of Laycock’s Mind and Brain, written in 1860, shortly before he died, shows how much he owed to the German Naturphilosophes. But he was also influenced by the mesmeric evidence. In an unpublished manuscript now in the Edinburgh University Library, Laycock narrates his earlier experiences in London when he encountered the bizarre automatisms of Elliotson’s notorious Okey sisters. Primed by his earlier exposure to German philosophical biology, the mesmeric evidence inaugurated what was to be a lifelong interest in the shadowy province between two kinds of behavior: the unarguably automatic and self-evidently voluntary.

However, as far as orthodox neurological opinion was concerned, there was no such province. On the contrary, the functions of the brain were not to be confused with those of the spinal cord. For example, according to Marshall Hall, one of the great pioneers of English neurophysiology,

The functions of the cerebral system [i. e., the brain] are sensation, perception, judgement, volition and voluntary motion. The cerebrum itself may be viewed as the organ of mind. It is the organ on which the psyche sits, as it were, enthroned. All its functions are strictly psychical. They imply consciousness. Sensation without consciousness appears to one to be a contradiction in terms. How different from those which I have just enumerated are the functions which belong to the true spinal nervous system. In these there is no sensation, no volition, no consciousness, nothing psychical at all.

Hall’s conclusions were based on animal experiments in which he destroyed the brain, leaving the spinal cord isolated but intact. In the animals which survived this maneuver a large repertoire of muscular reactions were preserved. Whereas more complex, volitional behavior disappeared altogether.

But it was not the experimental evidence alone that prompted Hall to make such a hard and fast distinction between the spinal cord on one hand, and the brain on the other. As a pious Christian who carried a Bible wherever he went, he was eager to establish a neural province within which the immortal soul enjoyed unquestioned sovereignty beyond the reach of profane materialism. Like Descartes, almost two hundred years earlier, Hall was prepared to make a large territorial concession to mechanism in exchange for a treaty which recognized the local sovereignty of the soul and the brain. The only difference was that whereas Descartes’s soul was confined to the somewhat cramped premises of the pineal gland, Hall furnished the spiritual monarch with the large upholstered apartments of the brain as a whole.

A hundred years earlier, La Mettrie had violated the Cartesian treaty by declaring that man was a machine through and through, indistinguishable from the automata created by the Swiss toymaker Vaucanson. And that although this imprudent Anschluss had been resisted, it was important to police the cerebrospinal frontier. So that when Laycock and Carpenter surrendered a large part of intracranial territory to reflex activity, there were those who understandably felt that the free will and sovereignty and, indeed, the divinity of man were in jeopardy.

Carpenter, however, who was just as pious as Marshall Hall, had no misgivings at all when it came to conceding the existence of what he called Unconscious Cerebration, which allowed mechanism to creep upward into the cranium itself. For one thing, the evidence in favor of it was by now incontestable, especially since Braid’s work had thrown such a strong light on it. And anyway, for Carpenter, the Will, being an unextended agency, could afford to lose a few ganglia to the encroachments of mechanism. Indeed, in a concession that was the neurological equivalent of Henri IV’s conceding that Paris was worth a Mass, Carpenter enlarged the province of the automatic to secure the sovereignty of the will.

Paradoxically, it was in the face of yet another mechanistic onslaught that Carpenter reaffirmed his argument in favor of the reflex function of the brain. In the preface to the fourth edition of his Human Physiology, he gave a summary of T.H. Huxley’s recent address to the British Association in Dublin.

Huxley had argued, in an article now entitled “Animals Are Automata,” that man himself is only a more complicated and variously endowed automaton. Huxley insisted:

The feeling we call volition is not the cause of the voluntary act, but simply the symbol in consciousness of that stage of the brain which is the immediate cause of the act. Like the steam whistle which signals but doesn’t cause the starting of the locomotive.

To support this claim, Huxley referred to many human automatisms, including the ones obtained under hypnotism. But that, according to Carpenter, was the point. The fact that hypnosis reveals so much in the way of automatism proved to him just how important the will was.

As Carpenter understood it, hypnotism induced a temporary suspension of the will, which then became all the more conspicuous by its absence:

The actions of our minds insofar as they are carried without any interference from our will may indeed be considered as functions of the brain. On the other hand, in the control which the will can exert over the direction of our thoughts and over the motive force of the feelings, we have evidence of a new independent power which may either oppose or concur with the automatic tendencies and which accordingly as it is habitually exerted, tends to render the ego a free agent.

In contrast to Marshall Hall, who felt that he had to limit automatism to the, as it were, below-stairs part of the nervous system—the spinal cord—to secure recognition of the spiritual independence of the will, Carpenter was convinced that he could achieve the same theological result at the comparatively modest expense of conceding the existence of automatic functions in the brain and not just in the spinal cord. It would be a mistake, though, to suggest that Carpenter merely conceded the existence of unconscious cerebration. For him, this process represented a function of considerable interest in its own right. So far as voluntary movement was concerned, it showed him how much automatic coordination was involved in executing a conscious act. Here is how he put it in 1876:

Even in the most purely volitional movements, the will does not directly produce the result. The will plays, as it were, upon the automatic apparatus by which the requisite neuromuscular combination is “brought into action.”

In each of these acts the coordination of a large number of muscular movements is required. So complex are their combinations that the professed anatomist would be unable to say exactly what is the precise state of each of the muscles concerned in the production of a given musical note or in the enunciation of a particular syllable. We simply conceive the tone or syllable we wish to utter and say to our automatic self, do this and the well trained automaton executes it. What we will is not to throw this or that muscle into action, but to produce a certain preconceived result.

This passage is virtually a paraphrase of a doctrine made famous by the great English neurologist John Hughlings Jackson, who argued that the cerebral cortex represents movements and not muscles, i.e., that we conceive an idea and throw the automatic self into action.

Now, under normal conditions, this automatic self, unconscious and reflex in character, is at the exclusive disposal of the will. But as Carpenter argues in the 1852 edition of his Human Physiology,

In those states in which the directing power of the will is suspended, hypnosis being one of them, the course of action is determined by some dominant idea which, for the moment, has full possession of the mind.

In other words, as the subject’s will weakened under the influence of hypnosis, the automatic apparatus of the brain, untouched by the hypnotic effect, is at the disposal of the operator’s will, and he is now in a position to dictate both the actions and the perceptions of the enhanced subject.

Neither Carpenter nor Laycock expressed any interest in the neurological mechanism whereby hypnosis brought about this submissive condition. As far as they were concerned, hypnosis, however it worked, was a conveniently reversible technique for diminishing the sovereignty of consciousness and exposing what Hamilton and Mill had previously suspected, i.e., that human beings owe a surprisingly large proportion of their cognitive and behavioral capacities to the existence of an “automatic self” of which they have no conscious knowledge and over which they have little voluntary control.


The role of hypnosis in developing this distinctively enabling view of the Unconscious has been regrettably overshadowed by its contribution to the more widely recognized Freudian Unconscious. In fact, the modern notion of the Unconscious is so closely identified with the one that figures in psychoanalytic theory that whatever celebrity Mesmer and his successors now enjoy is almost entirely the result of their being seen as antecedents of Freud.

Although there are self-evident points of resemblance, the notion of the Unconscious developed by British psychologists in the middle of the nineteenth century differs significantly from the one advanced by Freud at the end. In psychoanalytic theory, the Unconscious exercises an almost exclusively withholding function, actively denying its mental contents their access to awareness. Through the agency of repression, which Freud identifies as society’s censorious representative in the psyche, the individual is relieved of thoughts which might, if consciously experienced, compromise wholehearted cooperation in social life.

In contrast to this distinctively custodial interpretation, the Unconscious postulated by Hamilton, Laycock, and Carpenter figures as an altogether productive institution, actively generating the processes which are integral to memory, perception, and behavior. Its contents are inaccessible not, as in psychoanalytic theory, because they are held as in strenuously preventive detention but, more interestingly, because the effective implementation of cognition and conduct does not actually require comprehensive awareness. On the contrary, if consciousness is to implement the psychological tasks for which it is best fitted, it is expedient to assign a large proportion of psychic activity to automatic control: if the situation calls for a high-level managerial decision, the Unconscious will freely deliver the necessary information to awareness.

When represented in these terms, the Unconscious visualized by Carpenter and Laycock anticipates its role in late-twentieth-century psychology, and I suspect that if the long drought of Behaviorism had not taken place when it did, it would not have required an intellectual revolution to inaugurate the age of cognitive psychology.

As it is, though, by the end of the nineteenth century, the scientific community had become increasingly unfriendly toward explanations which appealed to mental processes that were publicly unobservable. Consciousness itself was bad enough, since it was, by definition, incorrigibly private, so the notion of a mental process, which was subjectively inaccessible into the bargain, struck many psychologists as perverse and unhelpful. The result was that the concept of Mind itself underwent an eclipse, and the experimental study of “behavior” replaced it. Psychologists devoted themselves to the study of the relationship between measurable stimuli and quantifiable responses, and preserved their scientific chastity by abstaining from speculations about the mental processes which intervened.

The new regime was accordingly christened Behaviorism, and for the next thirty years explanatory references to the “Mind” were regarded as academically suspect. Such discourse was confined to the scientifically segregated community of psychotherapy, with the result that the notion of the Unconscious acquired almost exclusively Freudian connotations and the role of hypnotism in promoting the discovery of the alternative version was forgotten.

The revival of the alternative, non-Freudian Unconscious began in the 1950s when its reconstruction under the auspices of artificial intelligence was one of the factors responsible for the timely decline of Behaviorism. As George Miller put it, the Mind returned to scientific psychology, legitimized by its metaphorical identification with the computer.

Research into automatic aiming devices during the Second World War had shown that the control mechanism needed to pursue and destroy an unpredictably moving target required an internal representation in which to register, update, and compute the relevant information. Although no one claimed that such an internal representation was conscious of its own deliberations, the necessity of such a mechanism gave credence to the notion of unconscious information processing and the so-called cognitive revolution ensued as a result.

Reconstructed in computational terms, the enabling unconscious, whose existence had been anticipated by Mill, Laycock, and Carpenter, began to figure mostly in psychological discourse.

One of the earliest expressions of this fruitful revival is to be found in the work of Noam Chomsky, who stipulated the necessity of covert mental activity to account for the distinctive creativity of language. In an epoch-making criticism of Behaviorism, Chomsky argued that it was impossible to explain our ability to utter and understand sentences that had never previously been spoken or heard without invoking the existence of a linguistic Unconscious capable of generating such versatile competence. He also drew attention to the deep syntactic resemblance between widely different natural languages and insisted that structural similarities required an abstract representation common to all of them. Although the details of this universal grammar were subjectively inaccessible, he argued, it consistently supplied the wherewithal for the rich diversity of conscious communication.

The revolution in linguistics has had its counterpart in almost every other department of psychology as Behaviorism has retreated in the face of evidence favoring the existence of what Carpenter had quaintly described as Unconscious Cerebration.

The remarkable phenomenon of “blindsight,” for example, bears witness to mental activity of which the individual has no explicit awareness. In patients blinded by injury to the visual cortex, Lawrence Weiskrantz and others were able to demonstrate behavior indicating that the subject had registered the occurrence of a visual stimulus without being subjectively aware of it. The patient was instructed to point toward small points of light unpredictably displayed within the “blind” sector of his visual field. Although he was reluctant to react to an “invisible” stimulus, when he was forced to guess where it might be, the accuracy of his pointing was significantly greater than chance. The fear that such a discriminating performance can be achieved in the apparent absence of visual experience indicates a perceptual competence operating well below the level of overt consciousness.

Comparable results have been reported in patients whom brain damage has robbed of the ability to put names to familiar faces. Such patients have intact language and normal eyesight so that they can correctly identify and name anything else they are shown. Their relatively discrete failure proves that a visual module specifically dedicated to facial discrimination has been destroyed. And yet further experiments indicate that this is not the whole story. When such patients are subjected to a variant of the forensic lie detector test, i.e., when their sweating is monitored by changes in skin conductivity, their reactions surpass chance whenever the photo of a well-loved face is thrown onto the screen. Although they are unable to consciously identify the familiar features, their emotional response proves that they have registered its familiarity, albeit unconsciously.

Experimental work with severe amnesia has yielded analogous results. Patients who consistently failed to identify test items to which they had been exposed some time earlier showed that the experience had unconsciously primed their attention to favor items related by meaning to the ones they seemed otherwise to have forgotten. Let’s say, for example, they had been shown a set of drawings representing musical instruments and that they failed to recognize any of them as having been seen before. When shown yet another set of drawings, one of which represented a musical instrument which they had not seen previously, they consistently favored that as opposed to drawings of unrelated objects.

And then there are Edoardo Bisiach’s remarkable observations of patients with a unilateral tendency to neglect or overlook items in their visual field; his findings showed that it is possible to possess and exploit a spatial representation of the imagined visual world without being consciously aware of it. The patients in question had suffered local damage to the right parietal lobe of their brain and as a result they showed a tendency to neglect or overlook items displayed in the left visual field. Unlike Weiskrantz’s patient, they were not actually blind in the affected field, but simply inattentive, since they would acknowledge and identify an object in it if their attention was forcibly drawn to it. Bisiach invited one such patient to imagine the view of the Piazza del Duomo in Milan, which was utterly familiar to him by sight before the onset of his illness. He asked him to visualize and describe everything that could be seen as viewed from the cathedral steps. The patient described only one half of what there was to be seen, insisting, nevertheless, that his description of the piazza was complete. When invited to list what could be “seen” when imagining the view from the opposite side of the piazza, i.e., when facing the cathedral, the patient fluently reported items which he had previously overlooked and claimed no knowledge of whatever.

Experimental results from an ever-widening range of psychological functions tell the same story, that what we are conscious of is a relatively small proportion of what we know and that we are the unwitting beneficiaries of a mind that is, in a sense, only partly our own.

The irony is, it has taken us this long to appreciate what some scientists were telling us more than a hundred years earlier. Yet another example of unilateral neglect!

This Issue

April 20, 1995