For most of recorded history, human beings situated the mind — and by extension the soul — not within the brain but within the heart. When preparing mummies for the afterlife, for instance, ancient Egyptian priests removed the heart in one piece and preserved it in a ceremonial jar; in contrast, they scraped out the brain through the nostrils with iron hooks, tossed it aside for animals, and filled the empty skull with sawdust or resin. (This wasn’t a snarky commentary on their politicians, either—they considered everyone’s brain useless.) Most Greek thinkers also elevated the heart to the body’s summa. Aristotle pointed out that the heart had thick vessels to shunt messages around, whereas the brain had wispy, effete wires. The heart furthermore sat in the body’s center, appropriate for a commander, while the brain sat in exile up top. The heart developed first in embryos, and it responded in sync with our emotions, pounding faster or slower, while the brain just sort of sat there. Ergo, the heart must house our highest faculties.
Meanwhile, though, some physicians had always had a different perspective on where the mind came from. They’d simply seen too many patients get beaned in the head and lose some higher faculty to think it all a coincidence. Doctors therefore began to promote a brain-centric view of human nature. And despite some heated debates over the centuries—especially about whether the brain had specialized regions or not—by the 1600s most learned men had enthroned the mind within the brain. A few brave scientists even began to search for that anatomical El Dorado: the exact seat of the soul within the brain.
One such explorer was Swedish philosopher Emanuel Swedenborg, one of the oddest ducks to ever waddle across the stage of history. Swedenborg’s family had made a fortune in mining in the late 1600s, and although he was raised in a pious household — his father wrote hymns for his daily bread and later became a bishop — Swedenborg devoted his life to physics, astronomy, and geology. He was the first person to suggest that the solar system formed when a giant cloud of space dust collapsed in upon itself, and much like Leonardo he sketched out plans for airplanes, submarines, and machine guns in his diaries. Contemporaries called him “the Swedish Aristotle.”
In the 1730s, just after turning forty, Swedenborg took up neuroanatomy. Instead of actually dissecting brains, though, he got himself a comfy armchair and began leafing through a mountain of books. Based solely on this inquiry, he developed some remarkably prescient ideas. His theory about the brain containing millions of small, independent bits connected by fibers anticipated the neuron doctrine; he correctly deduced that the corpus callosum allows the left and right hemispheres to communicate; and he determined that the pituitary gland serves as “a chymical laboratory.” In each case Swedenborg claimed that he’d merely drawn some obvious conclusions from other people’s research. In reality, he radically reinterpreted the neuroscience of the time, and most everyone he cited would have condemned him as a luna- and/or heretic.
The history of neuroscience might look quite different if Swedenborg had pursued these studies. But in 1743 he began to fall into mystical trances. Faces and angels hovered before him in visions, thunder pealed in his ears; he even smelled hallucinatory odors and felt odd tactile sensations. In the midst of these trances he often fell down shuddering, and an innkeeper in London once found him wrapped in a velvet nightgown, frothing at the mouth and babbling in Latin about being crucified to save the Jews. Swedenborg woke up insisting he’d touched God, and at different times claimed to have conversed with Jesus, Aristotle, Abraham, and inhabitants of the five other planets. (Uranus and Neptune hadn’t been discovered yet, or he surely would have met Uranians and Neptunians, too.) Sometimes the visions revealed answers to scientific mysteries, such as how bodies eaten by worms will nevertheless be reconstituted on Judgment Day. Other trances were more casual, like the time he brunched with angels, and discovered that some angels hate butter. Yet another time God pulled a mean joke and turned Swedenborg’s hair into a Medusa’s nest of snakes. Compared to such intense visions the cerebral pleasures of science had no chance, and from 1744 onward he devoted his life to chronicling these revelations.
Swedenborg died in 1772, and history has returned a split verdict on his legacy. His eclectic dream diaries charmed the likes of Coleridge, Blake, Goethe, and Yeats. Kant, meanwhile, dismissed Swedenborg as “the arch-fanatic of all fanatics.” Many other observers were similarly baffled. What could transform a gifted and reserved gentleman scientist into someone whom John Wesley called “one of the most ingenious, lively, entertaining madmen that ever set pen to paper”? The answer may be epilepsy.
At its most basic level epilepsy involves neurons firing when they shouldn’t and stirring up storms of electrical activity inside the brain. Neurons can misfire for many reasons. Some misfit neurons were born with misshapen membrane channels and can’t regulate the flow of ions in and out. Other times, when axons suffer damage, neurons start discharging spontaneously, like frayed electrical wires. Sometimes these disturbances remain local, and just one location in the brain goes on the fritz, a so-called partial seizure. In other cases, the seizure short-circuits the entire brain and leads to either a grand mal or a petit mal seizure. Grand mals (now called tonic-clonic seizures) start with muscular rigidity and end with the stereotypical thrashing and foaming; they’re what most of us think of when we think of epilepsy. Petit mals avoid the thrashing but usually cause “absences,” in which the victim freezes up and her mind goes blank for a spell. (William McKinley’s wife, Ida, suffered from petit mals. During state dinners McKinley sometimes just draped a napkin over her face and blustered through the next few minutes to divert attention.)
The triggers for epileptic fits can be bizarrely specific: noxious perfume, flashing lights, mah-jongg tiles, Rubik’s cubes, wind instruments, parasitic worms. Although potentially embarrassing, seizures don’t always compromise someone’s quality of life — and in rare cases, people benefit. Some first-time seizure victims find that they can suddenly draw much better or that they now appreciate poetry. Some folk (but only women so far — sorry, guys) orgasm during seizures. Specific triggers aside, seizures do erupt most commonly during times of stress or psychological turmoil. Probably the best example of this is Fyodor Dostoyevsky.
Biographers disagree about whether Dostoyevsky suffered any seizures when young, but he himself said that his epilepsy emerged only after his near execution in Siberia. Dostoyevsky and some fellow radicals were arrested in April 1849 on charges of plotting to overthrow Czar Nicholas. That December soldiers dragged the lot of them to a snowy public square studded with three tall posts. Until that moment the comrades assumed they’d get off with breaking rocks for a spell. Then a priest arrived, as did a firing squad, and clerks handed the prisoners white smocks to change into—funeral shrouds. Dostoyevsky grew frantic, especially when a friend pointed to a cart filled with what looked like coffins. Soldiers meanwhile marched the crew’s ringleaders to the posts and covered their eyes with white hoods. The gunmen raised their rifles. A minute of agony passed. Suddenly the rifles dropped, and a messenger clattered up on horseback, carrying a pardon. In reality Nicholas had staged the entire scene to teach the punks a lesson, but the stress unhinged Dostoyevsky. And after he’d spent a few months in a labor camp (the czar didn’t let them off that easy), the abusive guards and harsh weather finally pushed him over the edge, and he had his first major fit—shrieking, foaming, convulsions, the whole production.
That first seizure lowered the threshold inside Dostoyevsky’s brain, and after that, any mild stressor, mental or physical, could fell him. Guzzling champagne could trigger fits, as could staying up all night to write or losing money at roulette. Even conversations could detonate him. During a philosophical bull session with a friend in 1863, Dostoyevsky began pacing back and forth, waving his arms and raving about some point. Suddenly he staggered. His face contorted and his pupils dilated, and when he opened his mouth a groan escaped: his chest muscles had contracted and forced the air out. The seizure that followed was intense. A similar incident occurred a few years later, when he collapsed onto the divan in his wife’s family’s living room and began howling. (This couldn’t have impressed the in-laws.) Dreams could set him off as well, after which he usually wet the bed. Dostoyevsky compared the seizures to demonic possession, and he often plumbed the agony of them in his writing, including epileptic characters in "The Brothers Karamazov," "The Insulted and Injured," and "The Idiot."
Dostoyevsky almost certainly had temporal lobe epilepsy. (As mentioned, the temporal lobes sit behind your temples and wrap laterally around the brain, somewhat like earmuffs.) Not all temporal lobe epileptics thrash and foam, but many of them do experience a distinctive aura. Auras are sights, sounds, smells, or tingles that appear during the onset of seizures—a portent of worse things to come. Most epileptics experience auras of some sort, and most non–temporal lobe epileptics find them unpleasant: some unlucky folk smell burning feces, feel ants crawling beneath their skin, or pass horrendous gas. But for some reason—perhaps because the nearby limbic structures get revved up—auras that originate in the temporal lobes feel emotionally richer and often supernaturally charged. Some victims even feel their “souls” uniting with the godhead. (No wonder ancient doctors called epilepsy the sacred disease.) For his part, Dostoyevsky’s seizures were preceded by a rare “ecstatic aura” in which he felt a bliss so intense it ached. As he told a friend, “Such joy would be inconceivable in ordinary life . . . complete harmony in myself and in the whole world.” Afterward he felt shattered: bruised, depressed, haunted by thoughts of evil and guilt (familiar motifs in his fiction). But Dostoyevsky insisted the hardship was worth it: “For a few seconds of such bliss I would give ten or more years of my life, even my whole life.”
Temporal lobe epilepsy has transformed other people’s lives in a similar way. All human beings seem to have mental circuits that recognize certain things as sacred and predispose us to feeling a little spiritual. It’s just a feature of our brains (Richard Dawkins excepted, perhaps). But temporal lobe seizures seem to hypercharge these circuits, and they often leave victims intensely religious, as if God has personally tapped them as witnesses. Even if victims don’t become religious, their personalities often change in predictable ways. They become preoccupied with morality, often losing their sense of humor entirely. (Laugh lines are few and far between in Dostoyevsky.) They become “sticky” and “adhesive” in conversations, refusing to break them off despite pretty strong signs of boredom from the other party. And for whatever reason, many victims start writing compulsively. They might churn out page after page of doggerel or aphorisms, or even copy out song lyrics or food labels. The ones who visit heaven often chronicle their visions in excruciating detail.
Based on these symptoms, especially the rectitude and sudden spiritual awakening, modern doctors have retrodiagnosed certain religious icons as epileptics, including Saint Paul (the blinding light, the stupor near Damascus), Muhammad (the trips to heaven), and Joan of Arc (the visions, the sense of destiny). Swedenborg also fits the profile. He converted abruptly, he wrote like a methamphetamine addict (one book, "Arcana Coelestia," runs to two million words), and he often shuddered and fell down senseless during visions. On occasion he even felt “angels” thrusting his tongue between his teeth as if to make him bite it off, a common danger during seizures.
At the same time there are problems with casting Swedenborg and other religious folk as epileptics. Most seizures last a few seconds or minutes, not the hours that some prophets spend immersed in trances. And because a temporal fit can paralyze the hippocampus, which helps form memories, many temporal lobe epileptics can’t remember their visions in much detail afterward. (Even Dostoyevsky lapsed into vague descriptions when recounting their actual content.) Also, while Swedenborg’s trances in particular blended sights, sounds, and smells into a heady, heavenly froth, most epileptics hallucinate with one sense only. Most damningly, most epileptic auras are tedious, producing the same refulgent light, the same chorus of voices, or the same ambrosial smells time and again.
So while epilepsy might well have induced their visions — the idea makes sense — it’s important to remember that Joan of Arc, Swedenborg, Saint Paul, and others also transcended their epilepsy. Probably no one but Joan would have rallied France, no one but Swedenborg would have imagined angels eating butter. As with any neurological tic, temporal lobe epilepsy doesn’t wipe someone’s mental slate clean. It simply molds and reshapes what’s already there.
Excerpted from “The Tale of the Dueling Neurosurgeons: The History of the Human Brain as Revealed by True Stories of Trauma, Madness, and Recovery” by Sam Kean. Copyright © 2014 by Sam Kean. Reprinted by arrangement with Little, Brown and Company. All rights reserved.