Kepler's Witch Read online

  In July 1599, just after Tycho first arrived in Prague, Barvitius, the emperor’s private secretary, drove Tycho up the long hill in a magnificent carriage to a “splendid and magnificent palace in the Italian style, with beautiful private grounds.” There, inside the palace, he waited for the summons, holding three of his books to present to the emperor. A court attendant appeared, calling him forward and leading him to the emperor’s audience chamber. Reclusive Rudolf almost never received anyone alone. In a letter to Rosenkrantz, Tycho described the scene: “I saw [the emperor] sitting in the room on a bench with his back against a table, completely alone in the whole chamber without even an attending page. After the customary gestures of civility, he immediately called me over to him with a nod, and when I approached, graciously held out his hand to me. I then drew back a bit and gave a little speech in Latin.” Afterward, Rudolf, trained in Spanish manners, responded graciously to Tycho, “saying, among other things, how agreeable my arrival was and that he promised to support me and my research, all the while smiling in the most kindly way so that his whole face beamed with benevolence. I could not take in everything he said because he by nature speaks very softly.”

  After the audience, the emperor called Barvitius into the audience chamber. When Barvitius emerged, he told Tycho that the emperor had been watching his arrival from his window and had seen a mechanical device on his carriage. He wondered what that was. Tycho told Barvitius that it was his odometer and sent his son to remove the device from the carriage and bring it back to give to the emperor. He explained its workings to Barvitius and showed him how it rang out the passing distances by “striking distinct sounds with two little bells.”

  Barvitius reentered the audience chamber and after a time emerged once again, saying that the emperor did not wish to accept Tycho’s instrument, but wanted to have one built according to its specifications. Tycho happily supplied the design, knowing that the position he sought was his.

  From 1605 to 1606, the emperor’s artisans finished three different vaulted rooms on the first floor. Here the emperor displayed his vast collection of scientific instruments, some of the best in Europe, his books and manuscripts on scientific and arcane matters as well as his books on history and the great works of literature. In rooms beyond this library, was another library, stretching from the ceiling to the floor, known to writers across Europe as one of the greatest concerning all things scientific and philosophical. Meanwhile, exotic animals meandered through the labyrinth of corridors. In the floors below, the artisans worked in their workshop, where they made all of the wonderful machines and great devices the emperor prized so much. Beside the workshop was the alchemical laboratory, where alchemists from across Europe boiled up vats of unknown potions and experimented with secret elixirs.

  The entrance to the museum was through a small antechamber decorated with images of nature, with the four elements and the twelve months of the year, all watched over and supervised by Jupiter, Rudolf’s mythological self. In spite of his mythological pretensions, however, throughout the 1590s, the emperor’s depression deepened. He suffered from bouts of anxiety and despair, which became worse and more frequent. Visitors noticed how sad he had become and how remote. The golden collection could only keep his madness at bay for a time, however. Suddenly, his melancholy turned to paranoia, and he began to fear his own family, believing that someone in his family would eventually murder him. Once, in a sudden rage, he threatened one of his ministers with a dagger. Fearing theft, he kept most of his golden treasure locked away in wooden chests, which was one of the reasons why Kepler had difficulty obtaining his salary. At times, Rudolf’s fears swelled and he held on to his gold so tightly that there was no food in the palace. His greatest enemy, he believed, and not without reason, was his brother Matthias, the man who would eventually take over his throne.

  Matthias was not as intelligent or as open-minded as his brother. He had few talents except for the applications of power, and he used Rudolf’s interest in the occult to help bring him down, claiming that Rudolf was too easy with Protestants and that he dabbled in un-Christian things. Matthias did have ambition enough, and his desire for power and revenge on his older brother often choked him. Moreover, he was good at one thing Rudolf was not—he had a gift for intrigue. Rudolf hated him and feared him most of all. He took every opportunity he could to humiliate him, refusing him money and any position of power within the empire. He even forbade him to marry. After Ernest died in 1595, however, Matthias, who was next in line, became the imperial heir. Fearing the worst, Rudolf retreated more and more into his private quarters and into the galleries of his mechanical wonders, slowly abandoning the affairs of state, refusing to meet with foreign ambassadors, and flying into sudden rages.

  All of his relationships gradually fell apart. His sexual life was complicated, since he was attracted to both young boys and young girls. For years, he had been scheduled to marry his Spanish cousin Isabel, but postponed the wedding year after year. His mother begged him to marry in long letters sent from Spain, but somehow he found a reason to postpone it one more year. Finally, after waiting until she was thirty-two years old, Isabel married Rudolf’s younger brother Albert, the former cardinal. Hearing about their wedding, Rudolf raged about the palace in grief and anger.

  THIS WAS THE PALACE that Kepler came to after Tycho’s death and in which he joined the small clusters of attendants and imperial employees waiting for word on their salaries; occasionally he was summoned by the emperor to answer a question or perform some errand. A decade before, John Dee and the earless Edward Kelley, once alchemists and astrologers to Queen Elizabeth I, had haunted the castle, speaking with angels in secret and at least once, according to them, turning a pound of lead into a pound of gold. Kelley had lost his ears after being unmasked as a charlatan. The team gave alchemical advice to Rudolf until Kelley announced that the archangel Uriel had spoken to him in the night, telling him that he and his partner, John Dee, should share their wives. Dee’s wife, who was younger and prettier than Kelley’s, put her foot down, and from that point on the partnership faded.

  Ten years later, Kepler would have been standing in roughly the same place Dee and Kelley stood, in the vaulted Wenceslas Hall in the old royal palace or in one of the great rooms of Rudolf’s Italian palace, waiting in line or for an appointment. Perhaps, in one corner of the room was an old man standing quietly, the only Jew ever to have had an audience with the emperor. Kepler would have known him and perhaps spoken with him. This was the mysterious Judah Löw, the great rabbi of Prague, a master of the Kabbalah. The details of his interviews with the emperor remain unknown, even today, though there are stories. One has the rabbi ushered into a wide room with a single table and two chairs. In the corner is the opening to an antechamber covered with a red curtain. The man who meets the rabbi is not the emperor, but one of his councilors, who engages the rabbi in a long, involved conversation about occult matters. He asks Rabbi Löw about his teachings, about the mysticism of the Kabbalah, and about the secrets of the universe. The conversation becomes more involved, ranging widely, until suddenly Emperor Rudolf bursts into the room from behind the curtain, where he had been listening all the while. The rabbi and the councilor stand, the emperor takes the councilor’s place at the table, and the conversation continues.

  This same castle, filled in Kepler’s time with scientists and charlatans, mystics and philosophers, was where, seven years after Kepler had left the city, two Catholic representatives to the Diet, along with their secretary, were thrown out of a window in the old Bohemian chancellery. They survived, but the Thirty Years’ War began, the war that would hound Kepler to his tomb.

  LETTERS FROM KEPLER TO JOHANN GEORG BRENGGER

  OCTOBER4,1607

  I am just completing my studies on the movements of the star Mars, and this demands a good deal of difficult concentration. I offer a heavenly philosophy in place of the heavenly theology or heavenly metaphysics of Aristotle. Would that you read my wor
k and counsel me before I publish it! Vögelin in Heidelberg will print it, though the circulation of individual copies beforehand has been forbidden by the emperor. Besides my physics, I am currently teaching a new arithmetic…. Yet what a notion am I aiming at! It is not Mars who has incited me to write this book, but something else. “God is in us; if God sets us moving, then we are warming up.”

  NOVEMBER 30, 1607

  You think that the stars are simple things, and pure. I think otherwise, that they are like our earth. But experience cannot speak here, since no one has ever traveled to the stars before. Experience tells us nothing, therefore, neither yes nor no. In this, I am speaking of an inference I have made about the probable similarity between the moon and the earth. Conditions on the moon are closer to earthly conditions than we might think. In my opinion, there is also water on the stars…and living creatures as well, who exist only because of these earthlike conditions. Both that unfortunate man Giordano Bruno, the same fellow who was burned at the stake in Rome over hot coals, and also Brahe, of good memory, believed that there are living creatures on the stars.

  IX

  Living Creatures on the Stars

  Where Kepler writes the Astronomia Nova in Prague, a city full of magic and political intrigue.

  DURING THE YEARS KEPLER LIVED IN PRAGUE, from 1600 to 1612, he stayed in three different residences. The first was with Tycho in a house in Noy Svet, a neighborhood just west of Prazy Hrad, the Prague Castle, atop the great hill overlooking the city, a short walk for Kepler. Later, when he moved down to the Old Town, it was quite a walk up the Steep Stair, and then a leisurely walk down a narrow lane that worms over the hills until it ends. The houses, the buildings, the garden walls are all taupe colored, with red tile roofs and ornate gables. Old brass lanterns gone green are fixed to the garden walls. Tycho and Kepler’s house is No. 1 Noy Svet, hidden, nearly forgotten by the people dining at the fashionable restaurant next door. Kepler’s second home was across the street from the Emmaus monastery, Na Slovanech, near the church of St. John Nepomuk on the Rock. Both of these houses are in the New Town, across the river from the Old, both part of the maze of communities hustled around the walls of the old castle like supplicants calling for imperial favor.

  The last five years of his time in Prague, Kepler lived at 5 Karlova Street, across the road from the Jesuit residence inside the Counter-Reformation university, the Clementinum. This house was in the Old Town, on the other side of the river, a hundred feet from the Charles Bridge, eight or nine blocks south of the Jewish ghetto, and four or five blocks west of the Old Town Square. In the same square, Kepler’s friend Johannes Jessenius, the kindly anatomy professor from Wittenberg who acted as intermediary between Tycho and Kepler, eight years after Kepler’s departure from the city, as an example to the rebellious would be beheaded by Ferdinand II, once the Archduke of Styria, by then the Holy Roman Emperor.

  As in any medieval town, the streets of Prague are fit for pedestrians, horses, and small carts and wind a serpentine path up a gentle incline from the river. Nowadays, there are restaurants and shops selling textiles, marionettes, and Russian stacking dolls. On Karlova Street, just up from Kepler’s house, one shop sells Prague crystal, while a second sells linen. It is not difficult to imagine the same street in Kepler’s day, narrow, snaky, and stuffed with commerce—food sellers and wine merchants, stand-up bars, and traveling puppet shows. In the Old Town Square or near the foot of the bridge, the puppeteers played out folktales and morality plays. Traveling companies of players acted out national histories and fairy tales. Because there were no streetlights, the area around Kepler’s house at 5 Karlova Street fell asleep soon after dark, after the players and the puppet theaters had all packed up and moved on, after the street musicians had wiped the river air from their violins, gathered a few copper coins, and walked home. They glanced into each pocket of shadow as they walked, like everyone in Prague, wary of petty thieves. There were cutpurses aplenty in the capital, who would steal from monks as easily as from merchants. The river air carried the sour smell of decaying water plants mixed with the nose-twitching odor of animal death. In the fall and winter and into early spring, mists wafted up from the Vltava, covering the Charles Bridge and leaving only the towers sticking out of the white lake of fog.

  Prague is baroque with images, sometimes pretentious, sometimes saccharine, and sometimes mystical. A darker face hides truths that the city refuses to reveal. On the Charles Bridge is a statue celebrating the forced conversion of twenty-five hundred Jews to Christianity. The solemn, severe face of the preacher is matched by the subservience of the converted Jews, so that conversion becomes indistinguishable from conquest. The religious art haunting the city carries both spiritual and political messages, but underlying it is a grab for the numinous, an attempt to capture both the ecstasy and the torment of faith, where men and women alike are caught up in the folds of God. No art or science can in fact capture what the numinous is, for it is an encounter beyond words. Kepler tried to find it in the heavens.

  If Prague is astonishing for the jaded modern tourist, so used to heroic skylines and afternoon wonders, how much more astonishing it must have been for a man from provincial Leonberg. The architecture of royalty was constructed in layers, courtyard within courtyard, the old palace dominated by the massive Gothic towers of St. Vitus Cathedral, with walls as high and imposing as St. Peter’s, like fingers stretching upward, barely scraping the bottom of heaven. Kepler had made his mark in the empire, to be sure, but his situation as a Lutheran was always tenuous, and the titans who lived in Prague Castle, if only by turning over in their sleep, could create such waves as could easily swamp Kepler’s little boat. One can imagine Kepler, a man born in little Weil der Stadt, beginning at the foot of the castle stair and winding up the hill past the guard post to the stone walls, to the cathedral towers, to the ornate palace of the emperors. One can imagine his staring upward, as every ordinary mortal was expected to do, filled with insecurity and fear by the enormity of the architecture. In mimicry of the heavens; in mimicry of God.

  But anyone who was awake in Kepler’s day would have known, after a quick tour through the Old Town, that the emperors, for all their divinity, sat upon shifting sands. The city was too diverse for a simple, uncomplicated rule. No king could command the people. He either led them or terrorized them—there was little room for anything in between. Traditionally, three nations inhabited the city, twisting the folds of its history—the Czechs, the children of Libuše and Prøemysl, who first built it; the Germans, the countrymen and retainers of the Habsburgs, who ruled it; and the Jews, who lived as shadows, packed away in their ghetto, and suffered inside it. Of the three, the first two go back Roman times, while the Jews go back to the Middle Ages. The first two entered as settlers and conquerors. The last entered as refugees.

  The history of the Czech people has been like a man carrying a stack of dishes on his head; every day the neighbors clap, shout, pound the floor, rush at him, and make faces, because they want to see it fall. Magyars, Poles, Germans, Turks—all have conquered and all have been conquered. While the Habsburgs ruled, as they did for nearly a thousand years, the German minority dominated the city, hangers-on in the imperial Habsburg court. These were no working-class Germans. All were would-be aristocracy, mixed with a burgeoning bourgeoisie. In an aristocratic society, numbers didn’t matter; what mattered was power.

  Prague has always been a city of mystic spectacle. Whether from the mists that cover the Charles Bridge at night, from the alchemists and Rosicrucians, or from incursions of gypsies wandering through the city, Prague has always walked halfway in shadow. Although outwardly Catholic, the nation looks back to John Commenius and the Bohemian Brethren, to Jan Hus and the Utraquists, and feels that somehow something righteously Protestant has been stolen from it. Cuius regio, eius religio.

  Corresponding to Prague’s history of near madness—Rudolf II, Edward Kelley—is its history of genius—Tycho Brahe, Johannes Kepler. Kepler
wrote his first two mature works in Prague—the Astronomiae Pars Optica and the Astronomia Nova. In the former, he laid the groundwork for Newton’s later science of optics by setting out the rules of refraction. He discovered that the reason the moon or the sun appears larger at the horizon is optical, rather than astronomical. In the latter, his Astronomia Nova, he set up the first two of his three laws of planetary motion. These laws are:

  The law of ellipses: Each planet follows an elliptical orbit in which the sun sits at one focus of the ellipse.

  The law of equal areas: The radius vector joining a planet and the sun sweeps out an equal area over an equal period of time.

  To arrive at these conclusions, Kepler had to break with a great deal of tradition. First, the idea that the planets followed ellipses rather than perfect circles with uniform motion was near heresy. Even Kepler accepted the tradition as a reasonable starting place until he began his work on the orbit of Mars, when he eventually broke with it to make his theory fit Tycho’s observations. This was a new attitude. Astronomers in Kepler’s day were interested in accounting for the appearances, in creating a model that would apply geometry to motion, and the model often dominated. Although some astronomers were realistic enough to look for a relationship between the model and what actually happened, the reality they found was all too often simply an application of the model. Kepler took a different tack. He wanted to know what was actually happening, what the path of the planet actually was. In pursuing the secret of God’s mind, he had to be willing to be surprised. The Aristotelians, on the other hand, had a vision of the way a well-ordered universe ought to operate, for not only was the model true, it was righteously true.

  In Kepler’s day, reaching back through the Middle Ages to the time before Christ, to Aristotle, people assumed in a commonsense way that the heavens were perfect. They were silent; they were orderly; they were beautiful. Standing in an open field in the middle of the night, anyone could see the great vaulted heavens arching overhead and the blue-white stars, lucid and overpowering, scintillating in the night against the black background of the sky. Such beauty harrows the soul and purifies the mind, and for Aristotle and his followers such beauty had to be perfect, for imperfection was a thing of the earth, not a thing of heaven, the place where the gods lived.