Shortly before 10:00 on the evening of May 21, 1927, a plane dropped out of the clouds northwest of Paris. After flying over the city and twice circling the Eiffel Tower, it headed northeast toward the normally sleepy airfield at Le Bourget. No one could have been more surprised than the plane’s single pilot, an unknown American who looked more boyish than his twenty-five years, to see the teeming crowds awaiting him. When he landed his plane at 10:32 that night, the young man had been flying for more than thirty-three hours. By the time he fell asleep early the next morning—after fighting free from the crowds that pulled him from his plane, talking to the crush of international press that had gathered to cover his unprecedented feat, and taking a hot bath at the ambassador’s residence in Paris—he had been awake for more than sixty hours.1

By becoming the first human being to fly alone across the Atlantic, Charles Lindbergh went from an unassuming postal pilot to the world’s most famous person—literally overnight. His accomplishment was an example of extraordinary skill and courage, one that many others had failed to achieve in the years and months before, often perishing in the process. But the crowds at Le Bourget, and later in New York, and indeed everywhere Lindbergh would go from then on, weren’t just celebrating one man’s exploit.

For underlying Lindbergh’s undeniable skill—his flawless navigation alone and at night; his constant adjustment of altitude; his nerve-racking battle with fatigue—was a magnificent edifice of science and engineering that had just propelled a single human being in little more than a day across a distance that had previously required weeks and even months. This was an extension of the stunning human capacity for knowledge that had in recent centuries navigated the globe and built the railroads and would eventually place a man on the moon. A triumph of engineering, to be sure, but also of the laws of motion that Sir Isaac Newton had put to paper more than two hundred years earlier, and that had been powering humanity’s remarkable progress ever since. For in tracing that path from Roosevelt Field in New York to Le Bourget, Charles Lindbergh had moved a greater distance in a shorter time than any human in history. Little could he know that barely a thousand kilometers from the airport where he landed that evening, the very idea of what it means for an object to move through space was being turned on its head forever.

as lindbergh was making his historic flight, another young man was being driven to distraction in a quiet dwelling in Copenhagen. That was where the Danish physicist and Nobel laureate Niels Bohr waged a daily war of attrition against his twenty-five-year-old German assistant, Werner Heisenberg, dismantling the young man’s most recent paper in a relentless series of bombardments.

While not yet the full professor he would become later that year when he accepted the chair of theoretical physics at Leipzig, Heisenberg had already laid the groundwork two years prior for what would be formalized by the end of 1927 as quantum mechanics—a mathematical model of hair-curling complexity whose power is such that it continues to hold today, almost a hundred years and at least that many profound discoveries later. Heisenberg would himself win the Nobel Prize five years later for one of the two watershed papers he had written as a twenty-three-year-old. But the current battles with Bohr were about a new discovery, one that would shake the foundations of science and thought and be forever attached to Heisenberg’s name.

The debate revolved around the ultimate nature of reality. Classical physics had always assumed that objects followed the same laws of motion no matter their size. However, in 1913, Bohr had demonstrated that inside the atom electrons behaved rather differently than macroscopic objects, in that they occupied distinct orbits around the nucleus and appeared to “jump” from one to the other.2 The problem was this: If I jump from one step to another on my stairs, everyone will grant that I continue to exist along the way. Paradoxically, however, electrons show up in their new orbit without seeming to have traveled in between. Moreover, they seem not even to exist until they are detected, at which point they “decide” where they have been all along. It was as if Charles Lindbergh didn’t exist while crossing the Atlantic, and only came back into being when he was sighted over France.

on a saturday afternoon of the previous year, a deliriously happy young poet arrived at a party in Buenos Aires. Erudite, foppish, and timid, Jorge Luis Borges, known as Georgie to his friends, was attending a birthday luncheon for a fellow writer at the boating pond in Palermo Park. The source of Borges’s delight was on his arm that day, a rising novelist and poet of Scandinavian descent named Norah Lange.

It had been a good year for Borges. The Buenos Aires literary scene was starting to pull back from its sycophantic adulation of the European avant-garde, whose once risqué leaders were wealthy, settled, and now far more likely to be feted and pampered by the bourgeoisie than to shock them. This shift favored Borges, whose poetry at the time tended toward the romantic and locally flavored. While thoroughly cosmopolitan, his tastes were anchored in Argentina to the point where he and his literary compatriots would shower disdain on the musicians who dared to play faddish new forms of tango at the famed Café Tortoni.

In this group of friends Norah Lange shone like a lodestar. As one of the companions would later recount, deep into a night of drinking they would slip out to the corner bar “with the goddesses of that Wagnerian paradise.” Upon returning, “Norah, she of the long flaming hair, would regain her throne and scepter, extend both hands to silence the uproar, and proceed to recite … , her poems never failing to calm the storm and induce a sunrise of the purest emotion.”3 Indeed, in some of those poems we can sense her ardor for her lover and mentor Borges, which she likens to the “dew drawn to a freshly opened rose.”4

Borges, for his part, felt alive like never before. And his writing reflected that. The words of a poet, of any writer, had to amount to a fusion of souls, imparting the truths of one’s innermost experience; writing was to be “a full confession of the self.”5 Even under a fictional facade, the author’s autobiographical substance would be “like a heart beating in the depths.”6 Indeed, it would be fair to say that the relationship with Norah had provoked some uncharacteristic writing on Borges’s part. Carlos Mastronardi, a fellow writer and friend, would later recall that for one of the few times in his life Borges seemed to have little desire to be anyone other than himself. As Borges wrote at the time in an essay with the distinctly un-Borgesian title “Writing Happiness,” he couldn’t imagine “the negation of all consciousness, of all sensation, of all differentiation in time or space.”7 Mastronardi’s surprise was justified. His friend had a well-deserved reputation for morbid obsessions and had publicly mused that a human being’s sense of consciousness and identity over time was little else than a desperate illusion veiling an existential void.

Sadly, for Borges, if not for literary posterity, this reverie was not to last. On that spring afternoon at the party beside the lake, Norah shared a table with another writer, Oliverio Girondo, whose ease at conversation and charm with women contrasted starkly with Borges’s own awkward demeanor. As they chatted and drank, a tipsy Norah upset a bottle of red wine. Oliverio, never at a loss for words, leaned in and quipped, “Blood will flow between us.”8 The woman who came on Georgie’s arm was soon dancing with Oliverio. She would leave with him as well.

immanuel kant was obsessed with his bowels. During the summer of 1776, when elsewhere revolution was in the air, Kant couldn’t take a shit. A hypochondriacal bachelor in his early fifties and an established professor at the local university, he was in most respects entirely healthy. Indeed, he would live for another twenty-eight years, far longer than most of his friends and colleagues. Still, Kant’s digestive worries were a matter of great consequence. As he took his daily walks that summer, he had yet to publish a single one of the seminal works that would later earn his place as the founder of modern philosophy. His inability to get his gut in order was causing him to have confused thoughts—a considerable obstacle for someone aiming to put philosophy’s house in order. Finally published five years later, those thoughts would be complicated enough for those who would endeavor to read them, but in his current state of distraction Kant could barely make sense of them himself.

Not that Kant wished his...