The Question

How Johannes Kepler Defended His Mother from Witchcraft Accusations

His name might not immediately spring to mind like Galileo or Copernicus, but Johannes Kepler was one of the most important astronomers in history. He not only laid the groundwork of modern astronomy when he discovered the planets' orbits were elliptical, he set the stage for Isaac Newton to unify the force that moves the planets and the force that brings apples to the ground. (Put it this way: NASA doesn't name the search for Earth-like planets after you for nothing.) But in 1620, the motion of the planets was the furthest thing from his mind. He was too busy building a case to defend his elderly mother from accusations of witchcraft.

Johannes Kepler

Kepler v. Superstition

Imagine if you got a call that your mother's next door neighbor (the one who always hated her and who just-so-happened to owe her a great sum of money) had called the police on your mother for some heinous crime. And that the punishment for that crime isn't just death, but horrific torture. What would you do? If your name is Johannes Kepler, you pack up your already illustrious career in astronomy and head back home to defend her in court yourself.

Witchcraft accusations were no joke in the 17th century. The first person to accuse Katharina Kepler was, yes, a surly neighbor named Ursula Reinbold in 1615. Her trial dragged on for nearly six years, but in the last 14 months, the intensity ramped up. She was placed in iron shackles in a cell, and worse, according to "The Astronomer and The Witch" author Ulinka Rublack.

"She would have been shown the instruments of torture – they would screw thumbs with heavy irons, and sometimes the thumb would come completely off, causing excruciating pain. They would pull people up on a rack into the air. And she would be talked to in very threatening terms, all the time with a clear agenda to get her to confess." Can you imagine being a 73-year-old woman in 1620 (which is basically 134 in modern years) and being threatened with that kind of torture?

Science to the Rescue

Fortunately, Katharina had one of the world's premier scientists on her side. Her 49-year-old son put each of the accusations placed against her under the metaphorical microscope (literal microscopes wouldn't turn up for another 50 years). Kepler was able to use his knowledge of science and medicine to explain away her supposed "curses," from the illness that Ursula Reinbold claimed, to a story from a 12-year-old about an arm injury that never healed. And after six long years fighting those accusations, Katharina was finally a free woman.

Unfortunately, the story has a bittersweet ending. Although Katharina was not tortured or executed, she did not live much longer past her ordeal. She died six months after her acquittal, and the Kepler family was never the same. Not all of Johannes' siblings rushed to her side like he did — Margaretha was unable to leave her family, Cristoph withdrew his support when he began to feel threatened, and Heinrich, for some reason, joined in on the accusations. Confession time: we would totally watch this soap opera.

Want to learn more about how Johannes Kepler saved his mother from a horrific fate (and why he felt responsible for it in the first place)? Check out "The Astronomer and The Witch", by Ulinka Reinbold. Making any purchases from this link will help support Curiosity.

Cosmos: "Kepler's Persecution"

Written by Reuben Westmaas October 19, 2017

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