“A spindly middle-aged mathematician with a soaring mind, a sunken heart, and bad skin is being thrown about the back of a carriage in the bone-hollowing cold of a German January…He is now racing through the icy alabaster expanse of the countryside in the precarious hope of averting another: Four days after Christmas and two days after his forty-fourth birthday, a letter from his sister has informed him that their widowed mother is on trial for witchcraft — a fact for which he holds himself responsible.”

This is how Maria Popova of brainpickings starts her article entitled: “How Kepler Invented Science Fiction and Defended His Mother in a Witchcraft Trial While Revolutionizing Our Understanding of the Universe.”

It all started with Somnium (The Dream), Kepler’s work of science fiction.

Despite having sufficient mathematical evidence to confirm Copernicus’s heliocentric model of the universe, Kepler understood that the proof was overly complex and abstract to persuade his peers, much less the scientifically illiterate public. He realized that where data and evidence could not dismantle their “celestial parochialism,” storytelling could. Somnium resulted.

Somnium (The Dream), was a fictional account of a young astronomer who travels to the Moon. Rich in scientific ingenuity and symbolism, the allegory advanced the controversial Copernican model of the universe—that our planet revolves around the Sun, not the other way around. The young astronomer finds that lunar beings believe Earth revolves around them. Using the moon beings’ delusion as metaphor for our delusion about Earth’s central position in an immutable universe, Kepler hoped to awaken people to the truth of Copernicus’s heliocentric model of the universe. But we weren’t ready for the truth; instead Somniumresulted in Kepler’s elderly mother’s being accused of witchcraft. 

Popova adds: “As Kepler is galloping through the German countryside to prevent his mother’s execution, the Inquisition in Rome is about to declare the claim of Earth’s motion heretical — a heresy punishable by death.” This was a dangerous time for anyone with a scientific mind.

This was a world, Popova reminds us, where the will of God supersedes the laws of nature. A world where the Devil is more real and powerful than gravity. A time when most people believed that the sun revolved around the Earth every day in a circular orbit. Kepler would disprove this belief by demonstrating that physical forces move the heavenly bodies in calculable ellipses. But he paid a price for his unconventionality. Kepler was a game-changer, a scientific seditionist who would spill the apple cart of conventional thought with ungodly science. He invented the word orbit and developed a scientific method to predict eclipses. He was the first astrophysicist. And yet…

“All of this he would accomplish while drawing horoscopes, espousing the spontaneous creation of new animal species rising from bogs and oozing from tree bark, and believing the Earth itself to be an ensouled body that has digestion, that suffers illness, that inhales and exhales like a living organism,” writes Popova. “Three centuries later, the marine biologist and writer Rachel Carson would reimagine a version of this view woven of science and stripped of mysticism as she makes ecology a household word.”  

The superstitious villagers of Kepler’s hometown overlooked the metaphor and science of Somnium and focused instead on what they recognized as autobiographical: the young narrator (a young astronomer who apprenticed with Tycho Brahe like Kepler did) and a witch-like mother, who was a herb doctor (like Kepler’s own mother). Having recognized a likeness, they saw Kepler’s allegory as non-fiction. This meant that the narrator’s mother, who conjures up spirits to assist her son in his lunar voyage, and Kepler’s mother were one in the same. Katharina Kepler—a blunt, independent and outspoken woman—was soon called out as a witch. Villagers who had a bone to pick with her took advantage and rumors spread: a mother claimed that her daughter’s arm grew numb after Katharina brushed against it in the street; the butcher’s wife swore that pain pierced her husband’s thigh when Katharina walked by; the limping schoolmaster dated the onset of his disability to a night ten years earlier when he had taken a sip from a tin cup at Katharina’s house while reading her one of Kepler’s letters. She was accused of appearing magically through closed doors, of having caused the deaths of infants and animals.

“After years of exerting reason against superstition, Kepler ultimately succeeded in getting his mother acquitted,” writes Popova. “But the seventy-five-year-old woman never recovered from the trauma of the trial and the bitter German winter spent in the unheated prison.” She died shortly after she was released.

Thousands of people were tried for witchcraft during that time. Most of the accused were women, whose defense fell on their sons, brothers, and husbands. Most trials ended in execution. In Germany, some twenty-five thousand were killed. In Kepler’s small hometown, six women had been burned as witches just a few weeks before his mother was indicted.

Popova tells us that Katharina Kepler “first enchanted her son with astronomy when she took him to the top of a nearby hill and let the six-year-old boy gape in wonderment as the Great Comet of 1577 blazed across the sky.”

But Katharina’s fate was written by the world she lived in.  Kepler understood that as a man, his privileges in education—and standing—provided him with additional social standing beyond his mother’s. “I was born a man, not a woman,” he wrote, “a difference in sex which the astrologers seek in vain in the heavens.”