Kepler's Witch (19 page)

Longomontanus, homesick for Denmark, had already left Prague by the time Kepler had arrived, and so Kepler was able to take on the problem of the orbit of Mars once again. He worked on it diligently, as much as his health would allow, which would have been enough by itself, but Tycho assigned Kepler one more task, one that troubled him deeply. Returning to his old battle with Ursus, he set Kepler to work on a refutation of the dead man's ideas. Perhaps Tycho wanted Kepler to prove his loyalty, but more likely Tycho was just old-fashioned and an enemy was an enemy. Like Ahab after the white whale, he would not let go of Ursus and would chase the man into his grave and argue with his ghost. Kepler did as Tycho asked, though he found it a waste of time and believed that it was unseemly that men who studied the secrets of God would behave in this manner. As he wrote Tycho's defense, therefore, he did it with a remarkable sense of balance. He kept all personal rancor out of the text and, instead, refuted Ursus's hypotheses one at a time. In doing so, he defined what an astronomical hypothesis was, rejecting the idea that it was simply a matter of correct conclusions arrived at by calculation.

Then Kepler received word that old Jobst Müller had died, and in the spring of 1601 he traveled south to Graz once more to settle his wife's affairs. Surprisingly, in spite of all the threats that the archduke had fired at the Lutherans, Kepler wasn't arrested. No one in the Counter-Reformation seemed to care or even notice that he had returned. If he had stayed longer, perhaps they might have. The archduke's government in Graz looked the other way, and the Lutheran community, or what was left of it, warmly received him. The trip apparently did him a world of good. The fever abated, and he was able to travel in and around the city in some comfort. He had the energy to climb Mt. Schöckel, where he made measurements of the curvature of the earth and witnessed a strange thunderstorm.

In the midst of his joy, however, troubles exploded with Tycho once again. Tycho had promised Kepler that he would provide money to take care of Barbara and Regina while he was away, but then suddenly, while he was still in Graz, Barbara wrote Kepler a letter complaining that she was receiving too little money and that household goods were costing too much. She complained further that Tycho was too stingy and that life in Prague, for all its golden beauty, was not as gracious or as comfortable as it had been in Graz. Fired up, Kepler wrote to Tycho and passed on his wife's complaints is if they were his own.

Tycho angrily responded through his pupil Johannes Erickson that Kepler should consider what Tycho had already given to him and to his wife and that the Keplers should have more respect and be more moderate with their benefactor, who was helping them in every way possible. This angered Kepler in turn because he did not want to be a charity case; he wanted to be paid for his work, work central to everything Tycho was doing, and given the respect that one colleague would give to another. But as late middle age began to settle on Tycho, he was less and less willing to compromise. He had grown irascible, even with the powerful members of the emperor's court. He worried over his rejection by the Danish king and all the other events that had brought him to the emperor's court. For all his wealth and noble birth, Tycho had also come to Prague as a refugee. He was a man out of place in the city, and though he was well traveled, as he grew older he yearned increasingly for his homeland. As Kepler said, “He was not the man who could live with anyone without very severe conflicts, let alone with men in high position, the proud advisers of kings and princes.”
⁴
Gradually, the loss of his homeland, the stress of his position as imperial mathematician, and the pull and tug of imperial court life began to show on the old man, and he acted more like a petulant child.

At bottom, Tycho was a good sort with a good heart; he tried to do the right thing, but he was also feisty, and his own pride subverted him. In that, he was a lot like Kepler. Tycho protected his observations like a wolf guarding her cubs, and he showed Kepler only those observations that were germane to the work he expected Kepler to do. Such miserliness was a symptom of the age. Kepler was more open-minded than most, and in
some ways more modern. It infuriated him that other astronomers, including his teacher Michael Mästlin, refused to work with each other, guarded their own observations like dragons, and hoarded their data as if it were spun of gold. Throughout his career, Kepler encouraged other astronomers to share their work, to advance general knowledge, but got little response. Each astronomer was too worried about his reputation, his place in court, the opinions of his patrons, as if one man could own all knowledge. Tycho was typical of the times, more interested in advancing his own fame than the discipline. On Hveen, his island fiefdom in Denmark, he had set up a printing press to publish his works and observations. No other printer could touch the data, for Tycho demanded absolute control over his work.

After a few months, Kepler returned to Prague from Graz feeling well. The spat with Tycho had blown over, the fever that had plagued him had passed, and he had benefited from the kindness and hospitality of his old friends in Austria. Almost immediately, Tycho introduced him to the emperor, who received Kepler graciously and commissioned him to collaborate with Tycho in compiling new astronomical tables based on Tycho's observations. Tycho begged the emperor to allow him to name the tables after the emperor himself, which Rudolf agreed to, and so the new book would be titled the
Rudolphine Tables.
Kepler was included in the project as a collaborator, not an assistant or servant. Kepler's life had suddenly changed; his future was secure. Tycho also did something he had done with few others. Knowing that only Kepler could prove his Tychonic theory, Tycho entrusted him with his precious data, the keys to his heavenly kingdom. Kepler suddenly had everything he needed.

Then, however, his life changed once again. Kepler had been sick for nearly a year, and only through his trip to Graz had he been able to cleanse his body and soul. Now, suddenly, it was Tycho's turn. Things were going well between him and Kepler, and there was finally some peace in the house. Kepler had received the recognition he desired, and in the emperor's own words he was no longer a subordinate, but a collaborator. Then, suddenly, Tycho took ill, with an illness that would lead to his death. A few days after Tycho had presented his new collaborator to Em
peror Rudolf, he went with a friend, Councilor Minckwicz from the imperial court, to a luxurious banquet given by the old patron of Edward Kelley, Peter Vok Ursinus Rozmberk, at his house near the gate to the Prague Castle. The rules of civilized behavior at the imperial court were decidedly medieval and required that all guests remain seated at the table until the host finished his meal and signaled the end of the banquet by rising and leaving the room. According to an account of the event that appeared at the end of Tycho's personal papers and observations, an account that scholars later decided was penned by Kepler: “Holding his urine longer than was his habit, Brahe remained seated. Although he drank a little overgenerously and experienced pressure on his bladder, he felt less concern for the state of his health than for etiquette. By the time he returned home, he could not urinate anymore.”

Finally, with the most excruciating pain, he barely passed some urine. But it was still blocked. Uninterrupted insomnia followed, then intestinal fever, and little by little delirium. His poor condition was made worse by his way of eating, from which he could not be deterred. On October 24, when his delirium had subsided for a few hours, amid the prayers, tears, and efforts of his family to console him, his strength failed and he passed away very peacefully. With his death, his thirty-eight-year series of heavenly observations came to an end. During his last night, through the delirium in which everything was very pleasant, like a composer creating a song Brahe repeated these words over and over again: “Let me not seem to have lived in vain.”
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Kepler stood at Tycho's bedside with the family, and just before Tycho died, at nine or ten in the morning, he begged Kepler to carry on with his work, asking him not to abandon the Tychonic model of the universe entirely in favor of the Copernican. If he had to turn to Copernicus's plan, then he should at least follow through with Tycho's as well. The family buried Tycho on November 4 at Tyn Church in Prague in an Utraquist service. The Utraquists were pre-Reformation reformers peculiar to Bohemia, the followers of the long-dead martyr Jan Hus. Kepler was part of the funeral procession as a collaborator and a colleague, not an assistant. He composed and recited a long elegy for the service, for he never forgot
what he owed to his old master. Though he would never surrender his belief in the Copernican system, he did his best to show where the Tychonic system was still applicable to the motion of the planets.

Two days after Tycho died, the emperor declared Kepler his imperial mathematician. He sent an adviser named Barwitz to tell Kepler of his advancement and to inform him that the emperor had transferred the care of all of Tycho's instruments and works to him. Barwitz told Kepler that the emperor would bestow on him both a salary and a title, but of course he would have to apply for the salary. Given the state of the imperial bureaucracy, this alone signaled trouble for Kepler. Nevertheless, where he was once the assistant, now he was the master. He had control of all of Tycho's observations and could work freely for the first time in his life. His one great task was to prepare the
Rudolphine Tables,
and since little had been done on that project while Tycho was alive, Kepler needed to make mountains of calculations in order to finish it.

For the next few months, however, he stood in the hallways of the great Prague Castle, one of a small crowd of imperial employees who gathered in clumps about the castle. In a little over a year, he had risen from an outcast from Austria to the imperial mathematician. Surely, he thought, this was the hand of God. Congratulations flowed in from all over Europe. Kepler received a letter from Baron Hoffmann and another from Herwart von Hohenberg, both of whom were thrilled, and said so. Only Kepler, Herwart said, could replace Tycho Brahe. Knowing the Prague bureaucracy all too well, Herwart advised Kepler to ask for a salary commensurate with his mind and his importance and to seek an immediate down payment. Kepler listened to this, but sadly took the advice of other, less astute political minds and let the emperor fix the salary. Seeing a bargain, Rudolf offered him 500 gulden a year, one-sixth of what he offered to Tycho, a salary commensurate not with his mind, but rather with his social standing. The salary was expected to begin on October 1, 1601, but that didn't mean it would actually start then. Kepler, so unused to court life, spent the next few months shuttling back and forth from one office to the other in the imperial bureaucracy, looking for his pay.

Troubles also began about that time with Tycho's family. Although the
Brahe family legally owned Tycho's legacy, the emperor had given control over that legacy to Kepler since no one else could complete Tycho's great work. The family, led by the son-in-law, the same Tengnagel who had so abused Tycho's other assistants while courting his daughter, conspired to assure that the upstart Kepler would not profit from Tycho's work and that all fame, glory, and whatever money might come would go to the family—in Tycho's name, of course. Kepler tried to keep the peace and to respond with proper respect to Tycho's family, but the problems would only get worse as the
Rudolphine Tables
neared completion.

As a mathematician, however, Kepler had reached the heights. He was a member of the emperor's court, seemingly untouchable. But even there, the Counter-Reformation gathered around him. The old warfare between Protestants and Catholics was even more complicated in Prague than it had been in Graz. In Graz, there had been only two groups struggling for power. In Prague, there were three—the Catholics, the Utraquists, and the Bohemian Brethren. The Utraquists were founded when the more moderate followers of Jan Hus signed a treaty with the Catholic church on November 30, 1433. One of the Hussites' great complaints was the division between the clergy and the laity, symbolized by the fact that the clergy received Communion under both species,
sub utraque specie,
the bread and wine, while the people received Communion under only one, the bread. The Utraquists were therefore a form of liberal Catholicism, more schismatic than heretical. They held a middle ground, much as Anglicanism does in the modern world. The Hussite rebellion, however, was a violent one, with war and betrayal at the hands of church officials. In the fifteenth century, after a good deal of bloodshed, church officials invited Hus to a conference to discuss healing the rift between his followers and the church, and while he was on the road to the conference, the bishops sent soldiers to arrest him, try him, and finally burn him at the stake. Memory sears like a hot iron, and almost a hundred and fifty years later, the people of Bohemia could still smell the smoke of betrayal.

Into this mix of Catholics, Utraquists, and Bohemian Brethren, a more radical Hussite group, came Luther and his followers. Protestants began to split, and to split again. Some of the Bohemian Brethren formed a new
group called the Bohemian Brethren in the Bohemian Confession, which followed the Augsburg Confession in most ways, with a pinch of Calvinism thrown in. In 1556, however, the Jesuits entered the scene, as they had done in Graz. Peter Canisius, later canonized a saint, lead them, and his zeal was aimed at one thing—the reconversion of Bohemia to the Catholic church.

The Jesuits were missionaries and educators, founding colleges all over Europe, and they admired reasonable men. Complete union with the Society of Jesus required that one take a fourth vow over and above the traditional three of poverty, chastity, and obedience, a vow of special obedience and dedication to the pope. The Jesuits were therefore the most Catholic of Catholic orders. Throughout his life, Kepler had a complex relationship with them. Some Jesuits befriended him and gave him sanctuary when members of his own church would not. They supported him, promoted his work, and prayed for his conversion. From time to time, they passed on hopeful rumors wafting around Prague, as they had done in Graz, about Kepler's imminent conversion, but these were pipe dreams.