In Our Time - Emilie du Châtelet

Episode Date: February 4, 2021

Melvyn Bragg and guests discuss one of the outstanding French mathematicians and natural philosophers of the 18th Century, celebrated across Europe. Emilie du Châtelet, 1706-49, created a translation of Newton’s Principia from Latin into French that helped spread the light of mathematics on the emerging science, and her own book Institutions de Physique, with its lessons on physics, was welcomed as profound. She had the privileges of wealth and aristocracy, yet had to fight to be taken seriously as an intellectual in a world of ideas that was almost exclusively male. WithPatricia Fara Emeritus Fellow of Clare College, CambridgeDavid Wootton Anniversary Professor of History at the University of YorkAndJudith Zinsser Professor Emerita of History at Miami University of Ohio and biographer of Emilie du Châtelet.Producer: Simon Tillotson

BBC Sounds, music, radio, podcasts. Thanks for downloading this episode of In Our Time. There's a reading list to go with it on our website, and you can get news about our programs if you follow us on Twitter at BBC In Our Time. I hope you enjoy the programmes. Hello, Emily Ducatelais, 1706 to 1749, was an outstanding French mathematician and natural philosopher, celebrated across Europe. Her translation of Newton's Principia Mathematica

helped spread the light of mathematics on the emerging science, and her own book on the lessons of physics was welcomed as profound. And while she had the privilege of wealth and aristocracy, she had to fight to be taken seriously as an intellectual in a world of ideas that was almost exclusively male. With me to discuss Emily Dues Chatele are Patricia Farah, Emeritus Fellow of Clare College, Cambridge, David Wooten, anniversary professor of history at the University of York,

and Judith Sinclair, Professor Emerita of History at Miami University of Ohio and biographer of Emily de Chatelle. Judith, what was the world into which Emily de Chattelay was born? Well, it was a world of privilege. You know, we speak in the United States of the 1%. And she was certainly born into that world. French society was very stratified. And she came from the highest echelon of that society.

On her mother's side, she was related to the aristocracy of the court, the people who actually served the king. On her father's side, she was related to the aristocracy of the court administrators, the diplomats, people like that. So she was as well-born as you could be at that time. By the time she's 23, she actually knew Euclidean geometry, and she certainly knew Latin, probably also Italian. What's interesting is that she was raised in a very traditional fashion. She was supposed to be able to function at court. She was supposed to be charming and go to the theater and sing and dance and do all of the ladies' skills, so to speak. Did she do that? She did. She enjoyed what she called frivolous things. What's interesting is that by the

time she was 23, she did know this geometry, these subjects that women were not, young girls were never taught. So historians have hypothesized that perhaps her father taught her, but he was much too busy being an ambassador and serving Louis the 14th, who was king at the time when she was growing up. And in fact, I think that her education came in three sort of serendipitous stages. First of all, her younger brother, Teodor, was meant for the church, which meant that he had a tutor. And my guess is that between the ages of nine and 13, she probably sat in on his lessons. And he would have learned Latin and Euclidean geometry in preparation for his further training for the church. Stage two happened in the first years of her

marriage. She and her husband went to a garrison town in Burgundy. And there, after the birth of her three children, she actually became part of a little provincial salon. The man who led it was a mathematician from Paris. And it seems that he sparked her interest once again in mathematics, which she, everyone acknowledges at the time and now subsequently, she definitely was a mathematical genius. She had a gift for math and mathematical thinking. And stage three is when she returned to Paris, because having produced these two sons and a daughter,

she could leave and go back to frivolous things, so to speak, in Paris and enjoy society and whatever. And there was a mathematician and physicist, natural philosopher from the academy, a man named Mopertwe, who was quite a dashing fellow, and one of the ways in which he essentially amused himself and placed himself in French society was to give math lessons to the ladies. And Duchatelais jumped at the chance to have these lessons, and he passed her on to a younger colleague, a man named Clero,

who would remain her principal mathematics tutor off and on throughout the rest of her life. Thank you. David. David Wooden, who did she marry and how did that change her life? Well, she marries an aristocrat from a military family. The money is on her side. She marries up in social terms and brings a lot of money with her in her dowry. And she does the things that are expected of her young wife. She has children. And after five years of marriage, she starts having affairs with other people. And throughout the rest of their life together, her husband and she appear to have an entirely amicable relationship. He doesn't seem to have any concern about the affairs she has with other men. There's no evidence that he himself has affairs with other women. Perhaps he's just not very interested in these things. But it's a very successful marriage, and so far as they work together very well in the family enterprise

of promoting each other, and she works very hard on getting him better jobs. She works very hard on getting her children on in society, getting her daughter married and so on. And so this is a very successful family unit in the terms of the day. That's to say, They're loyal to each other. They look after each other.

They protect each other's interests very well. The most important of her lovers would have been Voltaire. Can you tell the listeners why he was important? Right. Well, they meet in 1733, and Voltaire is already the most famous poet in France. He's supposed to have written the greatest epic ever written, the first great epic written in French. And everyone assumes that epic is the greatest form of poetry.

So he's the greatest poet of the day. He's the greatest playwright of the day. He's written the most successful history book of the time. He is extraordinary phenomenon, and he's also a very wicked man in the context of the day because he's opposed to despotism in politics. He's opposed to the imposition of religious uniformity and so on. And so Volta carries with him this sort of frisson of naughtiness about him, and he's also very witty and amusing.

Slightly more than naughty, David. He's been in the Bastille a couple of times. He's been in the Bastille a couple of times. that's right. And he comes back from exile to England, and he publishes this work called The Lettre Philosophique, which really gets him into big trouble. And this is when he has, he and Emily have begun to take an interest in each other. She's been having an affair with Mopetri, the mathematician. Voltaire is in some sort of minor competition with Mopetri, and officials come to arrest Voltaire, and she takes him off to her chateau in the countryside

and protects him from the government. And this is, really the moment of which their relationship becomes fixed together. She decides that her future lies with Voltaire, that they are going to hide out in the countryside together, that she's going to protect him from the authorities, and they're going to form a little study circle together where they're going to intensely work her on mathematics, him on history, and become a sort of unit together. And it's an extraordinary decision because it means giving up the court life that she's been so engaged with. They've been after him. several times and caught him several times. How did she manage to protect him? Well, she's got good

connections at court. Her former love of the Duke de Ruisher is very powerful at court. She puts in, she says, if I keep him away from Paris, will you not come and arrest him? And they agree that this is, as it were, a decent deal, that she will keep him out of trouble. And for the next few years, she works very hard at keeping him out of trouble. She always opens all his post and takes away anything that looks as if it might provoke him into getting into trouble with the authorities. And she presumably looks at everything he puts in the post to go out to prevent him from getting into trouble. She's trying hard. I mean, she believes he's a great man, but that he's got this enormous capacity for getting himself into difficulty and getting himself potentially arrested and locked up for

the rest of his life. And her mission is to keep him out of trouble as far as she can and keep him to herself as far as she can. And she's very successful at this for 10 years, effectively. Patricia Farrow, what were the big questions in science in the early 18th century that are relevant to this story? Because Voltaire, after he'd been to England particularly, became very interested in Newton. Voltaire, after his visit to England, he wrote a book called Letters on the English. And it expressed his very, very strong admiration, almost infatuation with Isaac Newton. And it also summarised quite well two big questions that, were important for French people and for English people to consider.

And what the first was that Voltaire said, I left Paris and it was full, and I came to London and it was empty. And what he meant by that was under Rennie Descartes' philosophy, the whole cosmos, the whole universe is absolutely packed with tiny little particles, little atoms that are whizzing round and round and round and banging into each other. and according to Descartes, nothing can move unless something bangs into it. Isaac Newton's view of the cosmos was absolutely different.

He had vast tracts of empty spaces. So he had objects like the sun and the moon and the earth were attracting each other by some force, what he called gravity, over empty space. That was one very fundamental difference between Parisian science. and the science that prevailed in London. Were these the big questions in science at the time, or were there others which are relevant to this story? Yes.

The second big question was the shape of the earth, and this provided an objective way of distinguishing between the correctness of Cartesianism and of Newtonianism, because according to Descartes, the earth is sort of squashed in at the equator and slightly pointed at the poles rather like a lemon. whereas according to Isaac Newton's mathematics, it should be squashed at the poles and bulging out at the equator. And the conclusion? Well, the conclusion was helped along by Pierre Mopetouy, the mathematician who was teaching Emily de Chatele.

He was a great Newtonian and he led an expedition up to the Arctic Circle. And after a year or two, he managed to produce enough answers to convince him and everybody else that Newton was right and Descartes was wrong. So Pierre Mopatouille vindicated the Newtonian version of the shape of the Earth. Can we, do we know why Emily de Chattler immersed herself in mathematics so deeply in her mid-20s? Partly because she found them absolutely fascinating. She was very intrigued by what Mopatoui was doing. And then when she met Voltaire, he was absolutely passionate about Newton.

And she was far, far better at mathematics than Voltaire ever was. And it was just a subject that she absolutely loved and she was extremely good at it and she just wanted to learn more. And one of the great privileges of being rich was that she could afford tutors. She had three tutors altogether. There was Mopetri was the first. And then as Judith said, Alexis Clareau was the second. And later on, she had a German tutor called Samuel Kernick.

And he introduced her to the ideas of Leibniz. And that was very important as well. Thank you, Judith. Emily Dues Chatelle translated a scandalous English work, The Fable of the Bees. What does that tell us about her, and why was it scandalous? Well, it's part of the five years that she and Voltaire that David described that they spent at her husband's country Chateau. And while they were there, the first questions that they started reading about together, and they had these wonderful coffee hours in the morning with their hot chocolate, not coffee, but hot chocolate, was moral philosophy.

And Voltaire had brought back from England with him from his exile. He had brought back this book, The Fable of the Bees, by a Dutch emigre in London, Bernard Mandeville. And it was scandalous because in it, Mandeville argues that vice is what drives society and that it brings about virtue and prosperity. What is her attraction to it tell us about her? I think that originally what happened was that she,

Voltaire wanted to read it and use it in their thinking. Voltaire was working on a treatise on metaphysics, a treatise, a treatise on metaphysics, which he'd been working on for two or three years, and they're passing it back and forth, making comments to each other, and this book, I think, was one of many that they read in the course of preparing, helping Voltaire think out his theories on morality. And Duchatelais uses this to write a translator's preface. She talks about about the fact that the golden rule is what governs humanity, not vice. David, Emily de Chathleth and Walter lived together for, as you said, up to 10 years and they worked together. Can you tell us what influence they had on each other? How did he help her?

How did he help her? Let's start with how she helped him, as both Judith and Patricia have been saying. She was a much better mathematician than Voltaire was. And Voltaire embarked on this project of writing a book about Newton. And Volcher really wasn't competent to understand Newton very well. He read English guides to Newton. And clearly, Emily did Newton with him and for him and made sense of Newton with him and for him. And that became a joint project.

And when Volta publishes it, the preface says, you know, I couldn't have done this without Emily. It's very clear that he was very dependent upon her for that. And at that point, I think they have a common sense of the world. And then they embark upon a project of scientific experiment. There's been a announcement of a prize for an essay on the nature of fire. And they do a whole series of experiments. She happens to have an ironworks that she owns down on her estate. And they melt various things in the furnace and so on. And they do a range of experiments. And Volta's writing this essay on the

nature of fire. And then something shifts in their relationship. and it's a decisive moment, I think, Emily decides that Voltaire doesn't understand what he's talking about. And she goes off and secretly, in the dead of the night, she writes a different essay on the nature of fire, which she submits anonymously to the competition. Now, she has to do it anonymously because no one would take seriously an essay written by a woman. And it goes in, and Volta's essay goes in, and both of them are taking views which aren't approved by this. establishment so they don't win the prize and Voltaire starts writing and saying well why didn't my essay win and then Emily says well um Walter what about my essay and this is the first Volta's heard of this essay and then he starts very loyally trying to get her essay published and what she's done is take a

radically different view on the nature of fire from from Voltaire and already you can see that she's falling under the influence of the German philosopher Leibniz whom Volta loathed and from that moment on Volta and Emily are moving in different directions intellectually. And Voltaire says, you know, we have to live together and we have to practice tolerance with each other. Voltaire believes in tolerance with people you disagree with. And they learn to get on while disagreeing radically on questions of philosophy. It's such a unique relationship that they had. I mean, initially, as David suggested, it was sexual, but the sex is never that important to them.

and I think that what happens is that they really become, Voltaire at one point says that she was able to fill my heart and my mind and they remain intellectual companions even though they violently disagree to the end of her life and it's a remarkable friendship. I mean they would meet every day. They lived in the same place. This was true in Paris as well as while they were at Siri. It was true when they went to the court. There's a period when Voltaire actually has an appointment at court. It's really quite an amazing relationship. I like to think of her as Voltaire's companion rather than his lover. He admired her enormously. Voltaire once said that Minerva dictated and I wrote. So that was a huge tribute to Emily de Chateley as Minerva,

the goddess of wisdom. And he was enormously impressed by her intellectual abilities. When I said what influences you have on her, I partly meant was she promoting her? as a great scholar, despite the fact that she was a woman because there was great opposition to her and disbelief in that. Yes, he always supported her and promoted her, and he was very proud of her. I think one of the ultimate sacrifices that he made is that when she became pregnant by another man, not Voltaire,

but a third man called Saint-Lanbert, he suggested, will bring your husband back, convince your husband that it's the husband's baby, and everything will be fine. and that's what they did and then Voltaire stayed with her until the baby was born and then unfortunately Emily de Chatelle died

having a child was very dangerous in those days there was a lot of infection around but he supported her and he was absolutely grief-stricken when she died I mean they were very very close emotionally Can you give us some brief idea of the way she worked we were told she only slept three or four hours a night but did she have a working method?

She worked extremely hard. She said she put her fingers into ice-cold water in the middle of the night to keep herself awake. One of the things that I admire her about her the most is she said that the most important thing in life is to get pleasure from it. And by that she meant she loved gambling, she loved dancing, she loved nice clothes, eating, all that aspect of life. But she also believed that intellectual pleasure was extremely important. And when she was working on a project, she was absolutely committed to it 100%. And she had enormous enthusiasm for absolutely everything that she undertook. And that's what I really admire about her.

Judith, how well did she understand Newton? How good was her translation? Well, I think first she certainly understood the optics because that's what she and Voltaire used in his book on Newton. As far as the translation is concerned, it's really quite amazing because although it's in Latin, so we know that already that she knew Latin, but you can't just, it's not like translating, you know, my pen is on the table or something. To translate the Principia, you needed to understand what Newton was talking about. And in fact, there are places where what historians of Newton call fudges, there are places where he didn't quite know what to say and he made up sort of an answer and this and that.

And she actually had to work out in her translation than what she was going to say, how she was going to present those fudges. Another piece of it that is a measure of her understanding and her abilities is that he didn't use calculus in it. He had this very bizarre system of ratios or whatever that he used, and she managed to work all that out. Thirdly, I think, and this is perhaps one of the most interesting tributes to her, the man who did Bernard Cohen, who did the authoritative translation of the Principia into English, said of all the translations that had been done, the only one that was of any use to him was the one that she had done. Judith, she also did some work on the Bible. Could you tell me about that? Yeah, I think it's one of the most interesting things she did. There's no question that she and Voltaire, as part of this

investigation of moral philosophy, had embarked on reading what was a multi-volume, I'm like 25 volumes or whatever of a commentary on the Bible done by a biblical scholar, a Catholic biblical scholar. And in that, he basically presents all the arguments about each chapter and verse in the Bible and resolves them, of course, in line with Catholic doctrine. D'Shea de Chattelain Voltaire start arguing with this commentary on the Bible, with this description of the Bible, and she completes it on her own. Voltaire loses interest in it fairly quickly with other projects. and it's fascinating.

I mean, she says, she uses reason. I mean, for instance, she talks about the flood. It's literally chapter and verse. It's two long volumes. And for example, about the flood, she says, well, it couldn't, the flood doesn't make any sense, number one. And number two, she says, we know from the way in which swamps are that people could not have lived on, could not have survived when they got off the ark. God couldn't have created. Creation could not have taken seven days.

In other words, she goes through it rationally. They make great fun of Delilah, Samson and Delilah. She hates the God of the Old Testament. And perhaps most dramatically, in the sections of the New Testament, she used an English writer who refuted all of the miracles of Jesus, Jesus' miracles. And they're all a hoax. It's a scam. Lazarus was one of his buddies.

It's very dangerous writing. This was never published in her day. It was copied. It was passed around by hand. And, of course, it was attributed to somebody else for, over 100 years until they finally agreed that it was she. David, do we see the hand of Voltaire in those opinions of Emily? Well, again, this is a joint education effort.

They're engaged in. And if you look at the writings of Voltaire's in the 1760s and 1770s, he's drawing intensively on that same material. And almost certainly he's remembering their conversations that they had. And quite possibly he's consulting the manuscript of, of her notes. So in that sense, Voltaire, 20 years after her death, is carrying out this intellectual project of trying to demonstrate the intellectual failures of Christianity. Both of them share this view that revealed religion is completely intellectually unsustainable. Both

of them at this point are committed to a sort of deism which provides a rationalistic account of the world. She also challenged Newton, didn't she? She challenged the idea of he placed God in his universe, for instance? Yes, that is one of the disagreements that she, that's in a paragraph in her lessons of physics that she wrote. And it has to do with the fact that with the nature of matter, Newton believed that force dissipated in the universe and that periodically God had to intervene and actually replenish the force in the universe, what we would think of now more as energy.

And Dueschatelli thought that if you did that, then there could be no natural laws, because then you would be imagining that God perform miracles all the time and rearranged the universe and all of this. So how would we then have natural laws? It's also the point of view that Leibniz held. And Leibniz was very, very critical of Newton's view of God. He said Newton's God is like a sloppy watchmaker who's created the clockwork mechanism of the world, but he has to keep coming in to wind it up from time to time. And what Leibniz and Descartes both felt was that God had created the world. In particular, Leibniz felt that God had created the best possible world. And then once he'd created it, he absented himself from the universe. So Emily de Chattelay agreed with Leibniz on that point of view. In some ways, the most significant and fascinating aspect of her translation for people like me anyway is the commentary that she wrote on it. She decided that there was no point.

in just writing, doing this translation, unless she could explain not only more about Newton's view of the universe, in other words, how it actually works, but also, you know, describe it like the movement of the planets and comets and things, but also to add in work that had been done by French and Swiss mathematicians and physicists. In the meantime, in other words, to bring Newton up to date. And then for those who couldn't understand these ratios of his, she also included in her commentary a section where she was translating his mathematics into calculus, the major questions, the idea of the shape of the earth and what kind of effect the mass of the earth would have the shape of the earth and its mass would have on the interaction between the moon and the earth and the sun.

I think Newton would be rather angry about that because when Emily Ducatelais translated or transformed the Principia into calculus, she used Leibniz's form of calculus, rather than Newton's form of calculus, because she didn't actually realize that Newton had also invented calculus. And of course, Newton and Leibniz and their followers were absolutely at loggerheads about which one of them had invented calculus first. There is now a mathematician, a man who worked with Cohen doing the translation of Newton into English. And he says that she actually seemed to be inventing her own form of calculus. It definitely wasn't Newton's calculus. No, no, no, there's no question. It was a Leibnizian form of calculus.

and Leibniz's original calculus was developed. I mean, it's like all these topics. I mean, the kind of Newtonianism that prevailed at the end of the 18th century was very different from the form of Newtonism that Newton himself had proposed. So we like to think of Newton coming along and he sat under the apple tree and he conceived the theory of gravity and suddenly physics changed.

But it wasn't like that. It took the best part of a century and the collective work of many people among them, Emily de Chatelle, to convince people in the know that Newton's ideas were right. It was a long, slow, collaborative process. David Wooden, can you tell us at this stage

when she's done this, how was her reputation? Yes, just to pick up on what Patricia was saying, the story of Newton sitting under the apple tree, we, of course, owe to Walter, who's the first person to publish it. And Voltaire is the world's leading Newtonian. what Emily's reputation depended upon in part was her engagement into controversy which had split intellectual life among mathematicians and physicists, which was the question of how you understand

what happens when bodies banged together in movement. We think about Newton as being a science about billiard balls. And the question was, what happens when they've been billiard balls banged together? And the Newtonians said that you could understand the force that are moving, body had in terms of its mass multiplied by its velocity, its momentum, as we would now call it. And if you think, for example, if I were to fire a gun, I'd pull the gun into my shoulder, I'd pull the trigger, the bullet would come out one end, the stock of the gun would go back into my shoulder, and on Newtonian principles, action and reaction are equal and opposite. The force going into my shoulder is identical to the force of the bullet going out of the gun.

but when the bullet going out of the gun hits something, it does enormous damage. Well, my shoulder is hardly affected by the stock of the gun going back into it. And the followers of Leibniz said, the impact of the bullet has to be understood in terms of what we would now call kinetic energy, which is mass times velocity squared. That's to say, as you increase the velocity, you multiply the energy involved.

This is why it takes four times as long to stop. driving at 60 as if you're driving at 30. And if you run into somebody at 60, you do four times as much damage as if you run into them at 30. So we've got two theories about what's happening with moving bodies. One is the theory of momentum, the Newtonian theory, and the other is the theory of kinetic energy, as we now call it, for our live forces, as the Leibnizians called it. Emily comes out very strongly on the Leibnizian side, and she gets into an argument with the director of the Academy of Sciences in Paris about this, a man called Merin, and they publish attacking each other, and Voltaire publishes attacking Emily on this, just as Emily had published a negative

review of Voltaire's book on Newton. So this is an enormous split in intellectual life, and she is very clearly on the side. She's taken, within a few years, this whole issue is resolved by, eventually everyone agrees that there's right on both sides, there's both momentum and there's kinetic energy. And so Emily's role appears very important in a debate which within a decade has just disappeared out of intellectual life. She did carry out some very important experiments about to work out exactly what was happening. She spread out some soft clay on the floor and then she dropped balls onto the clay from different heights. And as David was saying, how we would explain that now is in terms of kinetic energy and also potential

energy. But that concept of energy was a very 19th century one. It didn't exist at all in the 18th century. And what she did was measure the depth of the indentation that the balls made. And she showed that what now seems obvious, but didn't at the time, was that the depth of the indentation was proportional to the height from which she dropped the ball. And I think that's a very good example of how she had a hypothesis and she tested it using an experiment, quite a straightforward experiment, And there was one of the important contributions she made because this idea of energy was absolutely crucial in 19th century physics. And it was one that Newton himself hadn't formulated. Patricia mentioned the word hypothesis.

And there's no question that she, her version of hypothesis, the way in which she talked about it in relation to the natural world and how you understand it and how you experiment to replicate conditions that are part of your. explanation, became part of the encyclopedia that Dieteroux produced in the 1760s, as well as a number of other sections of her lessons in physics. And it was they just lifted whole descriptions. But hypothesis I wanted to mention in particular because it is really the basis of modern science. You have a hypothesis, you perform experiments, you use mathematical models, and then when you have established enough probability and you can replicate it, you then assume that this is an explanation that comes close to the, quote,'s truth. David, we know that Emily worked extremely hard on her ideas. I think I've already mentioned. She only took three or four hours of sleep a night.

Was there any signs that she was frustrated by the obstacle she faced among this masculine hegemony? It's very interesting. In her essay on happiness that she worked on for quite a long time towards the end of her life. She says she's against ambition, but ambition, I think she means trying to get a better job, as it were, which is something that she couldn't possibly hope to have. She had ambitions for her husband and for her son. But what she's in favour of is the pursuit of glory. And by glory, she means reputation, fame. She is very determined to establish herself as a major intellectual figure. And at the end of her life, when she's pregnant and she believes, that there's a real prospect that she may die in pregnancy and in birth, which is what happens.

She packs up her Newton manuscript and her essay on happiness, and she sends them off to the Royal Library so that they will be held there. She's afraid that when she dies, her husband will just throw all her papers out. Well, he's not interested in this sort of thing. They'll be held there, and they can then be preserved for posterity. So there's absolutely no question that she sees herself as somebody who has the capacity, not just to be a scholar, but also to be a significant intellectual figure. And she wants to realize that capacity. Volta says that for a while after she's died, that she was a great man who happened to wear a dress. And that's what she wants to be. She wants to be a great man who happens to wear a dress. She wants to be somebody who's

recognized for her intellectual capacity and not for her sex. Patricia, what is it about Emily de Chattler's work that this most remarkable do you? I think in the Institutisien de Physique, the lessons on physics, I think it's a way that she tried to synthesise Descartes and Newton and Leibniz. So she just didn't just accept everything that Newton said wholehearted this. We talked a bit, Judith and I both mentioned the importance of hypothesis. And of course, Isaac Newton famously said, hypothet is known finger. I don't have any hypotheses in my work. So that was a very important way in which she actually differed from Newton. So she was able to consider these three great European philosophers and pick out the bits

that she believed were the best and synthesized them, synthesized them into her own version of what was essentially Newtonianism, but with a very, very Leibnizian flavour. She was very keen on metaphysics. And basically, most of that book is about the metaphysics. physical structure of science. And she speculated a lot about whether there's atoms and then she suggested following Leibniz that there's this rather immaterial units, so rather soul-like spirits called monads. She essentially regarded the universe as being divided into three tiers. So first of all, there's a visible world that we can see and that's what we do physics experiments on. And then we hypothesise that there's tiny atoms.

and they form, together they make up the matter that we see around us. But the trouble with the concept of atoms is that however tiny an atom is, you can always in principle divide it into something smaller. So she said, following Leibniz, that there has to be a third layer, a sort of non-material layer, something that doesn't extend out through space and therefore it can't be divided. And that's what Leibniz and Emily Chathlet called Monads. So that was her sort of philosophical view in which she took the best bits from everybody and created her own version.

Did she have any followers in that? You've outlined what she did, the three things she did. Did she have followers at that time? She certainly had a lot of admirers. I'm not sure if there was a sort of Chateley school. But her book was published in several different translations, in several different editions, and it was read all over Europe and widely admired. So in that sense, yes, she did have followers.

Were you trying to come in, Judith? It was translated into Italian and German. So that is a measure, it seems to me, of the respect that her ideas, the respect that was accorded her ideas. I think it's useful here to think about the fact that for Emily, what she's engaged in is philosophy. Science as a separate discipline doesn't yet exist. So that philosophy is something that,

provides you both with metaphysics on the other hand and with physics as well. So she sees herself as covering a range of issues that for us have become separated into the discipline of philosophy and the discipline of science. And so she addresses, she does something that seems to us paradoxical. She, on the one hand, is one of the first people in France to take experimental inquiry seriously. And she does a whole range of experiments. But on the other hand, she relies on abstract thinking of the sort of. that she's found in Leibniz. So Leibniz wants to say, God is, God must be all powerful and all rational. And so nothing God does can be arbitrary. So you can't, God must, for example, let's say God created

the universe 6,000 years ago. Why didn't he create it 7,000 years ago? Well, that would mean God had an arbitrary choice about when to create the universe. God can't have had any arbitrary choices. So clearly, God must have created time at the same time as he created the universe. In that sort of way, Leibniz decides on what the nature of time is, or what the nature of space is, by relying upon purely abstract deductive arguments. And Emily will take over a deductive approach to questions and an experimental approach and believe that she can make a harmony of the two.

Now, by the 19th century, that's disappeared. She's one of the last people who, like Descartes before her, believes that a new philosophy can also be a new science. And in that sense, I think she looks backwards as much, she looks forward. She was working on her translation of Newton right up to her death. Was there anything else that we know from her notice that she was turning her attention to at that time? Not that we know of. No, she was asked one of the mathematicians, one of the Swiss mathematicians, with whom she corresponded, suggested that she write about Patricia mentioned monads, but she

said, no, I'm not going to do that right now. And I think that her life at the point of, in 1748, when she dies, 1748-49 when she is pregnant and then her death, we really don't know exactly what she was going to do next. It's one of the speculations. Perhaps that she would write, in theory, there was to be a second volume to the lessons on physics, and maybe she was going to go back to that. She was known to go back to the Bible. She published two volumes on the Bible before she embarked on the translation. At the end of her life, she had Voltaire, and she had purchased a house that was sort of equidistant between Paris and the court. And this was to be where she and Saint-Lanbert and Voltaire would live,

and also in theory where her husband would come and whatever. I mean, it's amazing. So it was quite a remarkable arrangement. She was a multitasker, as they say, in the United States. Patricia, Patricia Parish, she dropped, Emily Chathlet, dropped out of view for many years. What brought her back interview? Well, I think she initially came back into view because there's been, ever since the 1960s, 70s, there's been an increased interest in women and science. I think more recently because of that, a lot of research has been done and more and more papers are appearing and pamphlets that she wrote during her lifetime.

So I think now she's important, not just as a female role model as a very, very unusually gifted woman. She's also increasingly seen as important for the contribution she made to the development of Newtonian physics during the 18th century. So it is that she's exceptional and extraordinary in being such an intellectual woman, but it's also that she played a very important scientific role. I don't think she's being retrieved simply because she's a woman. No, and I think the philosophers are the ones who most recently discovered her, and I think that they have now added to, all of our thinking about her as a natural philosopher as a philosopher because of her the ways in which she used Leibniz. Finally, David.

I wanted to go back to the question of what she's trying to do at the end of her life because I think we think about her essay on happiness and if we think about what's on her mind towards the end of the life, in a sense, the important thing she says in the essay on happiness, what matters is love. Love is the most important thing. She's fallen in love with San Lambert. She's devoted to him. She calls her love of him crazy, furious, wild.

When they're within 10 or 20 miles of each other, they'll exchange five letters a day each way. They'll send messengers and say, he's not coming back until he's got a letter from you. They're absolutely wildly. She certainly is wildly enamored of him. And so her ambition is, and she says it over and over again, that she will spend the rest of her life continuously in his company,

with him never leaving her again, with them never being separated. She's a complicated person. She thinks that love is the most important thing. Intellectual success is the next most important thing. Pleasure is the next thing after that. And she's tried with Volta to achieve a balance of those three. she tries in her life at court in gambling and she says I think we need also to respect her right to the end of her life she's singing opera in small productions she's performing in place

she's an extraordinary range of abilities but at the end of her life and at other times I think she believes that romance if you can use that word that sentimental attachment is more important than anything else, even more important than the intellectual life that she values so enormously highly. Well, thank you all very much indeed. Thank you, Julius and Sir, Patricia Farah and David Wooten. Next week, it's the Rosetta Stone, the vital clue to Egyptian hieroglyphs translated by Champolio and others in the 19th century. Thank you for listening. And the In Our Time podcast gets some extra time now with a few minutes of bonus material from Melvin and his guests. Well, one of the things I admire about

her so much is that she was just so passionate and whether it was her maths or her experiments or her love affairs or gambling or dressing she just did everything with total total enthusiasm and absorption and I think that makes her a marvellous role model for women and for men to live up to now I mean she had she didn't dedicate herself just to work

she covered the whole gamut of life yes when it when it came to gambling she said what she enjoyed doing was gambling for high stakes. And she says that by high stakes, I mean when you are in danger of losing enough money to change your life. And we know that on occasion she'd lost very large sums of money. She probably also made very large sums of money. It's harder to tell. So her gambling was a really high stakes enterprise.

It was a risky enterprise. And she took her family fortunes in her hands. and when she went to the card table. Well, it was also a way to be part of the court, I should add. It was a way to be part of the court, and she actually played against the queen, and you aren't supposed to win if you play against the queen. How did she deal with that, Judith?

With losing? Well, the thing about Emily is that she, about Madame Duchesselley, is that she had this mathematical mind, and I'm sure that she was like one of those poker players who knows all the cards that have been played. Did she beat the queen? No, no, as far as I know, never. The stories we have are anecdotes of Voltaire told.

They aren't necessarily ones that we can verify, shall we say, as a historian. I wanted to say there is one piece I really have to explain about my own view of Deschatelle, and it is a place where I disagree with the French historians, and David referred to it off and on, and that is really, her approach to affairs. And there's no question that she had one disastrous affair where she was ridiculed in society and everybody made fun of her. And that was before Voltaire. The problem was that, in fact, I don't believe there isn't any evidence, sort of definite evidence, that she had a whole series of affairs. And that was part of the way in which she was denigrated

as a female intellectual in the 20th century, the early 20th century, the late 19th century. century. And there is, she in fact had these very long-term relationships, first with, obviously, with her husband, and then with Voltaire, and then with Saint-Lombert. It wasn't as if she was, it was as if she were a serial monogamist, perhaps. The French historians tend to do this a lot with everybody. They'll have long lists of the people Voltaire is supposed to have had affairs with her and son. But I think, yes, you and I do have a slight disagreement on this. I mean, Madame de Grafini is convinced in 1739 that Emily has been caught red-handed, if I can put it like that, in flagrante delicto with the Duke Derichia with whom she'd had a long affair back before she'd met Voltaire.

Well, this is... Grafini is not to be trusted always. I'm afraid Graffini is not always to be trusted. She's probably jealous. Yes, I think so. I'm sure that's also true. But I think what we've got here is a core. society in which affairs, sexual entanglements,

liaisons, as they call them, are part of the normal aspect of social life. And she's very much part of that world. And Sam Lambert is very much part of that world. And the court at Lunéville is very much part of that world. And she's in a sense, I think a typical aristocrat, both male or female, of her day. And what is striking, I quite agree,

is this long-term, powerful relationship she builds, particularly with Volta and that she wants to build with San Lambert. And it's very clear that she wants to build a monogamous relationship with Sam Lambert. But they've only been close for, I think, slightly less than a year or slightly over a year, I guess. About a year and a half. At that point. Year and a half when she dies. So her hopes in this direction are never fulfilled.

But isn't part of the problem, we're only discussing this because she is a woman. Oh, no, we also. If she had been a man, we wouldn't be discussing her love affairs. We'd be discussing... We'd be discussing her science. I'd just like to talk a bit about what happened scientifically after she died, because I think that's quite important as well. She wrote that translation of Newton,

and it dissipated. No one knows what happened to it for the next 10 or 15 years after she died. And then in 1759, one of the people who'd been her tutor, Clareau, worked out a lot more Newtonian mathematics and calculated when Halley's comet was going to come back. And he got the date right within a few weeks. And when Halley's comet reappeared, that was one of the clinching pieces of evidence

that really vindicated Isaac Newton's theories. And somehow, nobody knows exactly how this translation by Emily de Chatterley reappe so there was a double event, There was a brand new translation of the Principia in French, and Edmund Halley's comet reappeared spot on time. So I think that that is a very significant part of the story, even though it happened after she died.

I'm so glad you added that, Patricia. And I think it's also rather on, we'd be talking about this baby. The baby seems to have disappeared. I think it was a little girl, and she was christened. I think she lived for about 20 months, I think. But then it's rather like the Newton manuscript the records of what happened to her

and what happened to the manuscript that have just vanished and the manuscript reappeared but unfortunately the baby died. Did her reputation disappear altogether for a while? Are we talking about 200 years or more of neglect, if you can put it that way?

Not so much in her own day for the next 10 or 15 years and then with the translation appearing in the commentary she was considered to be one of the learned women, an example of learned women. It's at the end of the 1800s that she really is forgotten by then, and partly as David explained, because of the changes in the way in which people thought about science and philosophy. And also the view of Newtonian physics was very different. By the end of the 19th century, there was this deterministic model that we have now,

in which God does not feature at all. And to include debates about God within debates about science became inappropriate towards the end of the 19th century. So she was seen as being very old-fashioned because to her and to Isaac Newton and to Leibniz, God was very important.

Well, thank you all very much indeed. That was terrific. In our time with Melvin Bragg is produced by Simon Tillotson. Teaching the kids at home can be tough. I'm Professor Brian Cox, distinguished physicists and astronomer known for exploring the quantum universe, and even I'm struggling. Well, help is at hand. The BBC are making education in lockdown more accessible than ever, with learning available for every child, every age, every day of the week. Online, on iPlayer, and now on TV as well.

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