Isaac Newton's Most Underrated Disciple Was a Pioneer for Women in Science

Émilie du Châtelet, the genius polymath who popularized Newton in continental Europe, got the historical shaft in last night's 'Cosmos'.

Becky Ferreira

Becky Ferreira

Émilie du Châtelet, rock star. Painting by Maurice Quentin de La Tour 

Last night's episode of Cosmos, “When Knowledge Conquered Fear,” was a passionate love letter to Edmond Halley. It was satisfying to watch, because Halley's genius is often overshadowed by the man he risked so much for: the epic weirdo known as Isaac Newton. 

It's difficult to speculate about what would have happened if Halley hadn't discovered that Newton was casually sitting on the blueprints to the universe in 1684. Maybe Newton, like Darwin, would have been spurred to action if he had seen his peers deriving the same laws—his battle with Leibniz over calculus certainly suggests he would not have idly stood by. But even so, it's undeniable that without Halley's patient assistance, the Principia Mathematica would have been greatly delayed, if it ever saw the light of day at all.

But Halley was far from the only person who went to bat for the insane British mathematician. And of all of Newton's disciples, the one who got the biggest historical shaft is the polymath Émilie du Châtelet, whose translation of Principia remains the standard French edition to this day.

Newton's personal copy of the Principia. Photo via Andrew Dunn.

Émilie du Châtelet was famous for centuries as little more than Voltaire's favorite girlfriend. But her genius was obvious from a very young age, and so was her endearingly modern attitude over whether a laboratory was really a woman's place. She simply did not give a rat's butt about all that noise.

Her nobleman father recognized her obvious brilliance when she was a child, and became her educational ally. Though there are conflicting reports about her mother's opinion on all this, the overall consensus is that she was scandalized by her daughter's budding mind, and tried to send her to a convent to straighten her out. It appears that the one time misogyny actually worked in Émilie's favor was in this parental debate, in which her mother's qualms were squashed by her father's support.

The education paid off, and fast. By the time she was 12, Châtelet could speak six different languages, knew the classic canon backwards and forwards, and could ride a horse and handle a sword. As a teenager, she used her mathematical genius to devise a clever system for maximizing gambling returns, and then used the winnings to buy books and lab gear. I know—I'm as confused as anyone about why this woman does not have a biopic, and this is just the beginning of her story.

As she developed into an intellectual powerhouse, her father began to share her mother's fears about her blatant disregard for gender roles “My youngest flaunts her mind,” he said, “and frightens away the suitors.” He need not have worried. Châtelet would have a lot of trouble getting men to accept her as an equal, but seducing them was not shaping up to be a problem. In fact, the abundance of suitors was more of an issue. She married the Marquis Châtelet-Lomont when she was 19, and it seems his leniency for her wandering eye was a central motivation for the match.

Her most famous lover was Voltaire, and together they would bring Isaac Newton's work to continental Europe. Voltaire was not only her intellectual match, he was her much-needed advocate. For years, Châtelet had been pulling out all the stops to gain access to the French scientific community but had been barred over and over due to her pesky lack of a Y-chromosome (though when she showed up to meetings dressed as a man, she was sometimes allowed in).

Châtelet had been obsessed with Newton since she first read the Principia, and felt she had been put on the Earth to spread the good word of Newtonian physics. But she knew she had the chops to build on his work too, and even corrected Newton's kinetic energy formula, which he had derived as E = mv. Leibniz had come to a different answer, E = mv², so she carried out the necessary experiments herself and discovered Leibniz was correct. Her proof laid the groundwork for Einstein's iconic formula two centuries later.

Voltaire used his fame as a springboard to help her get the foothold she needed, and together they published Elements of Sir Isaac Newton’s Philosophy (only Voltaire is credited, but the book is built on Châtelet's expertise). Newton's ideas were fighting a losing battle against Cartesian physics in France, and this accessible volume went a long way to shifting the balance in favor of the brave Newtonian world.

A sketch of the country house Châtelet and Voltaire shared via Rainer Zenz.

But her real magnum opus was her translation of the Principia, which cinched Newton's influence in France. More than a simple conversion of the Latin to French, the book included Châtelet's energetic musings, careful derivations, and several clarifications about what Newton—who could be frustratingly arcane—was actually trying to convey.

Sadly, Châtelet's translation was not just a passion project, but a swan song. After finding out she was pregnant at 41, she realized she'd better secure her intellectual legacy while she had the chance. For a woman of her time, getting knocked up at that age was a death sentence. She worked 18-hour days during her pregnancy, pumping out her translation with single-minded urgency, and died a week after the birth of a daughter.

Given her lifelong subversion of gender roles, it's hard to resist moulding her death into some kind of excruciating aphorism. Obsessed with birthing an Athena-style brainchild while dreading the delivery of her actual baby, it seems history decided to break out the big guns with this one, narrative-wise. It's one of the many reasons why the revival of interest in Châtelet is so essential and exciting. She didn't leave a mark in history—she kicked it in the face.

I'm not arguing that Cosmos should have brought up Châtelet during last night's episode, because Halley's life was more than enough material to work through. But what I like about the reboot so far is that each episode has presented a good skeleton of ideas and stories as a jumping off point for science and history nerds. From the debate about religion to the exaltation of pioneering thinkers, the show practically begs for takedowns, corrections, and introductions to underrated players like Châtelet. Kudos to the creators for stoking the fire.