Читать книгу The Invisible Century: Einstein, Freud and the Search for Hidden Universes - Temple Grandin, Richard Panek, Temple Grandin & Richard Panek - Страница 9

Listen.

And so the boy listened. His father had something to tell him. Hand in hand, they were going for a walk during which, in the manner they’d recently adopted, the father would attempt to impart to his son some lesson about life. On this occasion, the story concerned an incident that had happened to the father years earlier, on the streets of the city of Freiberg, the boy’s birthplace. The father, then a young man, had been walking along minding his own business when a stranger came up to him and in one swift motion knocked his new fur hat off his head, called him a Jew, and told him to get off the pavement. The boy dutifully listened to his father describe this scene, and he had to wonder: So what did you do? His father answered quietly that he had simply stepped into the roadway and picked up his cap. The boy and his father then walked along in silence. The boy was considering this answer. He knew his father was trying to tell him something about how times had changed and how the treatment of Jews was better today. But that’s not what the boy was thinking. Some three decades later, when Sigmund Freud recalled this scene, he couldn’t remember whether he had been ten or twelve at the time, but the impression he’d taken away from that encounter he could still summon and summarize drily: “This struck me as unheroic conduct on the part of the big, strong man who was holding the little boy by the hand.”

An impression, anyway. By the time Freud was committing this memory to paper, he was beginning to understand that any interpretation of the encounter on that long-ago day depended as much on what the boy had wanted to hear as on what the man had been trying to say, or even on what he, by now a father several times over, wished to believe about his father or himself, or about fathers and sons—depended, that is, on the vagaries of the human thought process. Not necessarily because of that conversation with his father (though maybe so; who knows?), it was the human thought process at the most basic level that Freud had grown up to explore: the pathways of nerves along which thoughts travel as they make their way through the brain. And so successful at tracing those paths were the neuroanatomists of Freud’s generation that they seemed to have reached, as one contemporary historian of science declared, “the very threshold of mind.”

That threshold was the neuron. Freud himself sought it, and in the early 1880s, as a young neuroanatomist fresh out of medical school, he even delivered a lecture before the Vienna Psychiatric Society about his own research into the structure of the nervous system. Although his subject that day was not specifically the ultimate point of connection between the fibers from two separate nerve cells within the human brain, he allowed himself a moment’s speculation on what form such a juncture might take, though he immediately, and judiciously, added, “I know that the existing material is not sufficient for a decision on this important physiological problem.”

Over the following decade, Freud metamorphosed from complacent researcher, pursuing his intuitions in a hospital laboratory in Vienna, to insecure clinician, struggling to establish a private medical practice so he could support a family, to some uneasy and perhaps unwieldy hybrid of the two, splitting his time between the laboratory and the clinic—between the theory and the practice of medicine. Yet even in private practice Freud continued to monitor neuroanatomical research as it raced toward its seemingly inevitable conclusion. If each central nerve cell in the brain exists in isolation from every other central nerve cell, as researchers had determined within Freud’s lifetime, it must still establish a connection with other central nerve cells. So: Where was it? Find that specific point of connection, as the neuroanatomists of Freud’s generation understood, and you’ll have found, at long last, the final piece in the puzzle of man.

As recently as the first quarter of the nineteenth century, that puzzle had seemed potentially insoluble, in large part because of the limitations inherent in the only instrument that might conceivably assist such an investigation. Back in the 1670s, when Antonius von Leeuwenhoek and other natural philosophers began reporting what they could see by examining terrestrial objects through a microscope, this new method of investigation might have seemed to offer limitless possibilities for anatomists. That promise, however, pretty much vanished once they got a good look at the infinitesimal scale of what they’d be studying. Leeuwenhoek himself reported that the finest pieces of matter he could see in animal tissue were simply “globules,” and for well over a century anatomists were left to concoct hypotheses about what these globulous objects might be without being able to see them any better than Leeuwenhoek had. As late as 1821, the English surgeon Charles Bell—who himself had only just recently distinguished between those nerves that carry the sensory impulses, or sensations, to the brain and those that carry the motor impulses, or instructions on how the body should respond, from the brain—gave up on the brain itself: “The endless confusion of the subject induces the physician, instead of taking the nervous system as the secure ground of his practice, to dismiss it from his course of study, as a subject presenting too great irregularity for legitimate investigation or reliance.”

Only five years later, however, British physicist Joseph Jackson Lister effectively revolutionized the microscope through improvements to the objective lens—the one nearer the specimen—that mostly eliminated distortions and color aberrations. Before this advance, neuroanatomy hadn’t been much more than speculation supported by inadequate, incomplete or imprecise observation—supported by further speculation even. Now a new breed of anatomist could explore tissue at a level of detail that was literally microscopic—the technique that would become known as histology.

In 1827, only a year after inventing his achromatic microscope, Lister himself (along with the physician Thomas Hodgkin) decisively refuted all the variations on Leeuwenhoek’s “globular” hypothesis that had arisen over the preceding century and a half. The globules, it turned out, were illusions, mere tricks of the light that Lister’s new lens system could now correct. By utilizing the achromatic microscope to examine brain tissue, Lister reported, “one sees instead of globules a multitude of very small particles, which are most irregular in shape and size.” To these particles anatomists applied a term that the first microscopists back in the seventeenth century had used to describe some of the smallest features they could see, though now it came to refer only to the basic units of organisms, both plant and animals: cells. These cells, moreover, seemed always to be accompanied by long strands, or fibers. That a relationship between these cells and fibers existed in the central nervous system—the brain and spinal cord—formed the basis of Theodor Schwann’s cell theory of 1839, a tremendous advance in knowledge from even fifteen years earlier. “However,” as one researcher reported in 1842, “the arrangement of those parts in relation to each other is still completely unknown.”

Some researchers argued that the fibers merely encircled the cells without having an anatomical connection to them. Some argued that the fibers actually emanated from the cells. Such was the density of the mass of material in the central nervous system, however, that even the achromatic microscope couldn’t penetrate it sensibly. Despite the promise of clarity that Lister’s improvements at first had seemed to offer, by the 1850s anatomists were beginning to resign themselves to the realization that the precise nature of the relationship between cells and fibers would have to remain a mystery, unless another technological advance came along.

It did, in 1858, two years after Freud was born, when the German histologist Joseph von Gerlach invented microscopic staining—a way to dye a sample so that the object under observation would bloom into a rich color against the background. The object under observation in this case was a central nerve cell, complete with an attendant network of fibers. Now neuroanatomists could see for themselves that the fibers and the cells were indeed anatomically connected. They could also see that the central nerve cells exist only in the gray matter of the brain and spinal cord, never the white. And they could see that even where a central nerve cell is part of a dense concentration within the gray matter, it exists apart from any other central nerve cell, in seeming isolation.

But if the cells themselves don’t come into contact with other cells, then how do they communicate with one another, as they clearly must? How does one cell “know” what the others are doing and therefore act in concert and thereby register a sensation or commit the nervous system to a response, an action, a thought? If the answer wasn’t in the cells, those solitary hubs, then it had to be elsewhere.

And the only elsewhere there was, was the fibers. Thanks to Gerlach’s staining method, neuroanatomists now found that the fibers extend from the central nerve cells only into the white matter of the brain and spinal cord, never the gray. But there the trail went cold. The meshwork was still too intricate for anyone to trace the paths of all the fibers from a single cell to the point where the fibers terminate. And so yet another technical innovation needed to be invented, and so yet another one was. In 1873—the same year that Freud entered the University of Vienna as a medical student—Camillo Golgi, an Italian physician, developed a superior staining method that in effect isolated the fibers in the same way that Gerlach’s had isolated the cells. Even so, researchers still couldn’t find one point of connection between the fibers of two different cells. Golgi himself thought he found one in the 1880s, but his sample was inconclusive. Still, in order to do what central nerve cells do, which is pass along impulses to one another, both prevailing theory and common sense dictated that the fibers of neighboring cells must connect, somewhere.

Not until 1889 did the Spanish histologist Santiago Ramón y Cajal discover the truth: They don’t, anywhere. This, then, was the basic unit of the brain, what the German anatomist Wilhelm Waldeyer two years later would name the neuron: each central nerve cell and its own fibers, existing apart from—that is, not connecting to—any other central nerve cells and their own fibers. But if even the least wisp of a fiber—a fibril—doesn’t connect, what does it do? It contacts, Ramón y Cajal explained. It reaches out, under the excitation of an impulse, to touch the neighboring fibril or cell, and then, when the excitation has relaxed, it retracts to its previous state of isolation. “A connection with a fiber network,” Waldeyer wrote, “or an origin from such a network, does not take place.”

Although at first the “neuron doctrine,” as Waldeyer christened it, might have seemed to contradict common sense, upon reflection the idea that communication between individual neurons was not continuous but intermittent actually went a long way toward a possible explanation of several otherwise inexplicable mental phenomena, such as the isolation of ideas, the creation of new associations, the temporary inability to remember a familiar fact, the confusion of memories. These were the phenomena, anyway, that Freud had been confronting in his private practice, where he found himself listening at length to hysterics, and wondering how to represent their worries and cures within the webwork of cells and fibers he remembered from his years of neuroanatomy.

“I am so deep in the ‘Psychology for Neurologists’ that it quite consumes me, till I have to break off overworked,” Freud wrote to a friend in April 1895. “I have never been so intensely preoccupied by anything.” By now Freud had embarked on a second career. From 1873 to 1885, first as a medical student and then as a medical researcher, he’d devoted himself to an examination of the nervous system—to research in neuroanatomy. In 1886, on the eve of his thirtieth birthday, he’d opened a private practice devoted to nervous disorders and, for the first time in his life, begun seeing patients, though he continued to conduct research on the side. After the development of the neuron theory, Freud would have had every reason to believe that if anyone were in a position to unite the psychical with the physical, it was he. He’d seen both sides. He’d studied both sides, immersing himself in the peculiar logic of each for long periods of time. He’d even written some tentative outlines to this effect over the past few years, in letters to his closest friend and constant correspondent, Wilhelm Fliess, a Berlin ear, nose, and throat doctor. Not until Freud could meet with Fliess personally late in the summer of 1895, however, and the two men could convene one of their days-long “congresses,” as Freud liked to call these occasional periods of intense and inspirational professional discussion, did he see the project whole.

Freud began composing the manuscript on the train ride from Berlin back home to Vienna that September. “I am writing so little to you only because I am writing so much for you,” Freud informed Fliess by letter on September 23. Barely two weeks later, on October 8, Freud mailed a draft to Fliess—a hundred or so handwritten pages in which he attempted to explain definitively the processes of the mind by describing exhaustively the mechanism of the brain that encases it.

And a mechanism it was. “The project,” Freud wrote, in the second sentence of the manuscript, “involves two principal ideas”: in essence, and in accord with Descartes’s philosophy and Newton’s physics, motion and matter. Freud’s principal idea number I was straightforward enough: that the workings of the brain are “subject to the general laws of motion”—that matter moves immediately adjacent matter with comprehensive cause-and-effect predictability. What contributed to Freud’s sense of urgency in composing this draft, however, was that he now knew what the “matter” was: “2. That it is to be assumed that the material particles in question are the neurons.” He based this assumption, as he made explicit several pages later, on “the knowledge of neurons which has been arrived at by modern histology.”

Yet even as he was passing the manuscript along to Fliess, Freud was starting to have his doubts. “I have been alternately proud and overjoyed and ashamed and miserable—until now, after an excess of mental torment, I apathetically tell myself: it does not yet, perhaps never will, hang together,” he wrote in the accompanying letter. “I am not succeeding with the mechanical elucidation; rather, I am inclined to listen to the quiet voice which tells me that my explanations are not yet adequate.”

In the weeks to come that inner voice softened briefly, then hardened again. “During one industrious night last week,” Freud wrote to Fliess on October 20, twelve days after posting the manuscript, “the barriers suddenly lifted, the veils dropped, and everything became transparent—from the details of the neuroses to the determinants of consciousness. Everything seemed to fall into place, the cogs meshed, I had the impression that the thing now really was a machine that shortly would function on its own.” On November 8, however, he reported that after other professional commitments had forced him to put the manuscript aside, he found he couldn’t stop thinking about it—specifically, he noted with regret, that “it required a lot of revision. At that moment,” he went on, “I rebelled against my tyrant. I felt overworked, irritated, confused, and incapable of mastering it all. So I flung it all aside. If you felt called on to form an opinion of those few sheets of paper that would justify my cry of joy at my victory, I am sorry, because you must have found it difficult.” Freud added that in another two months, after he’d fulfilled his obligations, “I may be able to get the whole thing clearer.” It was not to be. Only three weeks later he wrote to Fliess, “I no longer understand the state of mind in which I hatched the psychology; cannot conceive how I could have inflicted it on you. I believe you are still too polite; to me it appears to have been a kind of madness.”

Maybe so. Whatever it was, it was over now, as if a fever had broken. The problem that Freud had found himself confronting was larger than pathways of nerves, larger than the neuron itself—or, maybe, smaller. Either way, it was the same problem that had been haunting physiology since the inception of the modern era more than two centuries earlier: brain. To be precise, it was brain in opposition to what the motions of matter within the human cranium represent: mind, maybe.

For much of human history, such a distinction would have been secondary, at best. The far more important distinction, instead, would have been the one between two types of matter: terrestrial and celestial. Down here, as Aristotle had said, were the four elements—earth, air, fire, and water, either alone or in any number of combinations. Up there was one element—quintessence, a single perfect substance that constituted the moon, sun, planets and stars, as well as the spheres that carried them on their heavenly journeys. An Earth that itself traveled through the heavens, however, not only erased the crucial distinction between what was terrestrial and what was celestial but—as Descartes appreciated when he was merely a budding philosopher—presented a strong argument that everything in heaven and everything on Earth might ultimately consist of the same stuff.

Descartes first heard about Galileo’s discovery of four moons orbiting Jupiter in 1610, as a student at the Jesuit college at La Flèche. Although Descartes was only thirteen or fourteen when this astonishing news reached his outpost in the French countryside, he understood at once the profound effects such a discovery could have on philosophy and physics. The very scope of those effects, however, also reinforced for him two growing suspicions: that although philosophy “has been cultivated for many centuries by the most excellent minds,” as he later wrote, “there is still no point in it which is not disputed and hence doubtful”; and that as “for the other sciences, in so far as they borrow their principles from philosophy I decided that nothing solid could have been built upon such shaky foundations.” The only rational approach to this appalling and ongoing state of ignorance, he concluded, was to begin again, from the beginning—“to demolish everything completely and start right again from the foundations,” and to do so by seeking “no knowledge other than that which could be found in myself or else in the great book of the world.”

The World, in fact, was what he called his first attempt to explain all of physics. As was often the case with Descartes when he produced a work of physics, he simultaneously produced a companion work on how a reconception of physics would necessitate a new interpretation of man’s role in it—a new physiology. This work he called Treatise on Man. He completed both in 1633, a year after Galileo released his own attempt at a new physics, Dialogue Concerning the Two Chief World Systems. But before his two volumes could reach publication, Descartes heard that the Roman Catholic Church had condemned Galileo because the Dialogue posited a sun-centered universe. Since his own two essays did the same and since he feared that if he altered them in any way they would be “mangled,” Descartes suppressed both.

But he never stopped working on physics and physiology. In particular, over the next few years, he wondered if the newfound conceptual unity between the heavens and the Earth would allow him to achieve a parallel mathematical unity. In other words, could he do to the terrestrial realm what astronomers had long done to the celestial realm: geometricize it? Geometry, after all, had originally been an attempt to render the terrestrial world in mathematical terms. Now, after a lapse of a couple of millennia, it was again, and in his 1637 Geometry, Descartes demonstrated how all matter, not only in heaven but on Earth, could be located according to three coordinates in space. In which case, as Descartes himself recognized and as succeeding generations came to appreciate, a crucial question presented itself: Could we approach the secrets of man’s inner universe with the same heretofore unthinkable curiosity that Galileo and his successors had regarded the outer? Could we render the motions of matter within the brain as predictable as any planet’s through the heavens? In short, could there be a Newton of neurology?

Even while Newton was alive and evidence had begun to accumulate that his laws extend to the outermost reaches of the universe, the question inevitably had arisen whether those same laws might extend to the innermost reaches as well. In 1725, Richard Mead, an English physician, had produced mathematical formulations of the effects of planetary gravity on the human body. Expanding on that idea later in the eighteenth century, the German physician Franz Anton Mesmer proposed a gravitational attraction between animals, or what he called animal magnetism, whose existence he then claimed to demonstrate through public displays of hypnotism. In the early nineteenth century, efforts at quantifying psychic phenomena found a champion in the German philosopher Johann Friedrich Herbart, who conceived of the workings of the mind as “forces” rather than ideas, who explicitly invoked Newton in advocating the use of mathematical formulas to describe the motions of these forces, and who once declared, “Regular order in the human mind is wholly similar to that in the starry sky.”

In retrospect, though, any such earlier efforts to reduce the workings of the inner universe to a series of cause-and-effect laws were doomed. These would-be Newtons couldn’t have known it at the time, but they didn’t yet have access to a Galilean equivalent of neuroanatomical data—the moons, planets, and stars of the inner universe—to provide their speculations with a solid empirical foundation.

Did Freud? It was tempting for him to think so. It would have been tempting for anyone in his position to think so—not only because it’s always tempting for an ambitious intellect to think that the generation into which it’s fortunate enough to be born is the one in possession of just enough information to settle a question that has thwarted the great thinkers since antiquity but because the state of neuroanatomical knowledge at the close of the nineteenth century was different from any other period in the history of science. In fact, in 1894—only five years after Ramón y Cajal’s discovery that fibers from central nerve cells contact, not connect, and only three years after Waldeyer developed the neuron theory—one of Freud’s former instructors and colleagues from his laboratory days, Sigmund Exner, published his own attempt at a comprehensive neuroanatomy, Entwurf zu einer physiologischen Erklärung der psychischen Erscheinungen (Draft Toward a Physiological Explanation of the Psychological Features).

Like most physiologists of his era, Freud knew firsthand what the achromatic microscope could accomplish. He’d used the still-new instrument extensively as a student in the 1870s, then proved his mastery of it the following decade as a reliable, respected diagnostician at the General Hospital of Vienna, where one of his examinations drew praise in a contemporary medical journal for its “very valuable contribution” to a field “heretofore lacking in detailed microscopic examination.” And like many physiologists of his era, Freud knew firsthand what staining a microscopic sample could accomplish. He’d twice developed his own significant improvements on existing staining methods, first in 1877 “for the purpose of preparing in a guaranteed and easy way the central and peripheral nervous system of the higher vertebrate (mice, rabbits, cattle),” and again in 1883 “for the study of nerve tracts in the brain and spinal cord.” And like a few physiologists of his era, Freud had even anticipated the neuron theory itself, during his lecture before the Vienna Psychiatric Society in the early 1880s, several years before Ramón y Cajal proved it. Unable to locate a fiber that he could trace from one central nerve cell to another, he’d wondered if cells might therefore not ultimately connect.

In the wake of his failure with the “Psychology for Neurologists,” however, Freud began to consider another way to frame the problem: not as mind in opposition to brain—or at least not only mind in opposition to brain. Instead he began to think in terms of mind in opposition to itself.

“The starting-point for this investigation,” Freud later wrote, outlining his reasoning at this juncture, “is provided by a fact without parallel, which defies all explanation or description—the fact of consciousness.” On the most basic level, the workings of the mind remained a mystery. Even a thought, the fundamental unit of mind, doesn’t remain in consciousness for any length of time. “A conception—or any other psychical element—which is now present to my consciousness may become absent the next moment, and may become present again, after an interval, unchanged.” Forget for the moment the gap within the brain—between one neuron and the next, that space across which some “quantity” of “energy” must pass, as he’d tried to express the transaction in his “Psychology.” And forget, too, the gap between brain and mind—between the physical communication among neurons and the resulting psychical impressions. With this description of one of the most mundane of human occurrences—something out of “our most daily personal experience”—Freud had identified a gap within the mind itself: “In the interval the idea was—we do not know what.”

“Unconscious,” he called it, adopting the common adjective of the time. In a sense, all he’d done was work his way back to the assumptions that he and his contemporaries had inherited. Mind was mind, brain was brain, and one day, maybe, the two would meet. Brain anyone with the proper training and equipment could tease the secrets out of, slicing tissue, staining samples, subjecting fibrils to microscopic scrutiny at recently unthinkable powers of magnification and degrees of resolution. Mind, however, nobody could fully capture using a mechanical model of the brain—not yet, anyway. Mind, as Freud could observe for himself on an almost daily basis in his private medical practice, was simply full of too many subtleties whose precise nature continued to doom any attempt to do for the physical workings of the inner universe what Newton had done for the outer.

But, in another sense, what Freud had learned through the experience of writing that manuscript was just how subde the subtleties of mind were. Nothing in his neurological training had prepared him for—or, as he had now learned the hard way, could account for—that. Under intensive scrutiny, the mind had turned out to be even more complicated—far more circuitous, far more contradictory, and, finally, far more elusive—than he or, as far as he knew, anyone else had begun to imagine. Brain might be simply brain, but mind wasn’t just mind.

As he reclined in a chair in his modest study in Vienna, listening to the complaints of patients week after week, year after year, Freud had learned to encourage them to try to see whether they could remember the trauma that had caused their hysterical symptoms. If they did so, as he tried to reassure them, their symptoms would disappear. Freud had first heard about this method many years earlier, back in 1882, from a friend and colleague in Vienna, the eminent physician and medical researcher Josef Breuer. At that time, Breuer had told Freud about how he’d treated a young woman’s hysteria through hypnosis. Freud, in fact, had seen a demonstration of hypnosis once. It was, he thought, impressive, especially for a student with a physiological turn of mind. But instructive? Curative?

It might be so, said Breuer. Rather than simply issuing a command or a prohibition while she was under hypnosis, he said, he had asked this patient—Anna O., Freud named her later, when recalling this period in his professional development—what the source of the trauma was. In her waking state she “could describe only very imperfectly or not at all” the memories relating to her trauma, as Freud later wrote; in a hypnotic state, however, she seemed oddly able to remember everything. Even more improbably, by recalling the source of the trauma, as well as by experiencing the emotional outpouring that invariably accompanied this memory, she seemed somehow to slip free of the grip of the memory—seemed to achieve, in Breuer’s term, a “catharsis.”

In order for this construct of a cure to hold, it might seem, the mind must work like a Newtonian machine: an initial cause leading to an effect, which in turn becomes a cause for another effect, which in turn becomes another cause for a further effect, and so on, insinuating itself throughout the subject’s life until one day, in an unrecognizable guise, it surfaces as hysteric behavior, those worrisome symptoms that prompt the victim to seek medical attention. But if this description of the process were true, then the removal of any link along the way would be sufficient to interrupt the chain of causality and lead to the removal of the ultimate effect—the hysterical symptom. In that case, using hypnosis in a purely suggestive way, by simply commanding the symptom to disappear, would be sufficient in effecting a cure.

Freud, however, believed that he’d seen otherwise. When he attempted to apply this kind of therapy in his own medical practice, he found that leading the patient back to some step between the current state of hysteria and the original inciting incident didn’t have a cathartic result. Only by revisiting the scene of the crime, so to speak, could a victim permanently break free of its memory, its insidious influence. Only by tracing it to its source would doctor and patient see the hysterical symptom disappear—but only by tracing it all the way to its source. As Freud told a meeting of the Vienna Medical Club in January 1893, “The moment at which the physician finds out the occasion when the symptom first appeared and the reason for its appearance is also the moment at which the symptom vanishes.”

Anna O., for instance, complained of a paralysis on her right side, persistent hallucinations of snakes in her hair, and a sudden inability to speak her native German. These symptoms Breuer eventually traced back to an evening when she was nursing her sick father and imagined a snake approaching his sleeping figure. She tried to move to save him, but her right arm had gone to sleep over the back of a chair; and so she resorted to prayer, but in her fear all she could recall were some children’s verses in English. Or, from Freud’s own case files, Frau Cäcilie M., who suffered from a pain between her eyes until she remembered the time her grandmother had fixed her with a “piercing” look. “Cessante causa cessat effectus,” as Freud said in that same lecture before the Vienna Medical Club: “When the cause ceases, the effect ceases.”

Freud, however, wasn’t content with a vision of the mind that began with a cause and then, no matter what, ended with a certain effect. How to account for the inability of a process so powerful—so active, after all—to reveal itself?

With his background in a physiology that was ultimately nothing more than matter and motion, Freud knew exactly how to account for it: by postulating the existence within the unconscious of an opposing force at least equally powerful—a “defense” or, as Freud soon came to call it, a “repression,” a change in terminology that itself reflected a change in Freud’s thinking. This opposing force wasn’t merely defending the mind against itself; it was repressing the unpleasant memory or association. It wasn’t reactive. It, too, was active, even while seemingly absent.

On October 26, 1896, Freud’s father died. The heroic figure of Sigmund’s childhood imagination may have disappeared forever during that long-ago walk when the father confided in the son how he’d submitted to the indignities of an anti-Semite, and now the corporeal figure was gone, too. Yet they lingered—both the heroic figure and the tragic shade. Like a traumatic event that remains present in the symptoms of a hysterical patient, the older man remained alive in the grown son. That night, in fact, Freud had a dream about him. On his way to the funeral, Freud stops at a barbershop. There he sees a sign: “You are requested to close the eyes.” Whose eyes? he had to wonder. The dead father’s? The son’s? And “close” them as in lay to rest? Or “close” them as in “wink at” or “overlook”?

The dead-but-not-gone father wasn’t the only thing that lingered. The dream did, too, taunting Freud with its myriad possible interpretations, haunting him like the earlier memory of the about-to-be-unheroic man on the street, inhabiting him, continuing to exert its influence over him, as an adult, decades after the event. In years to come, Freud more formally commemorated his father’s death as “the most important event, the most poignant loss, of a man’s life.” But now, when his impressions were raw, he confided in a letter to his friend Fliess, “By one of those dark pathways behind the official consciousness the old man’s death has affected me deeply.”

Could Freud navigate those dark pathways? When he tried to map the pathways of nerves within the brain, he had failed—and now he suspected it was because he’d set himself the wrong challenge. Now a new and radically different challenge presented itself to him: How to map the pathways of the mind alone? Even if he could, would anyone believe that such a description bears any resemblance to reality? He would, of course—but then, sitting in his office, listening to his patients, Sigmund Freud had heard the evidence for himself, if only in his mind’s ear.