Emilie du Châtelet 1706-1749
(Born Gabrielle-Emilie Le Tonnelier de Breteuil; also du Chastelet) French mathematician, physicist, translator, and essayist
A leading physicist of eighteenth-century France, du Châtelet is as well known for her works on Newtonian physics as she is for her romantic relationship with Voltaire. Scholars from throughout Europe traveled to Voltaire and du Châtelet's intellectual retreat at Cirey to study and perform research with the famous couple. Voltaire declared that his understanding of physics was largely due to du Châtelet's explanaton and assistance, and her works on Newtonian physics, including the Institutions de physique (1740) and her 1758 translation of his Principia Mathematica, set a standard that lasted for centuries.
Du Châtelet was born Gabrielle-Emilie Le Tonnelier de Breteuil to an aristocratic Parisian family. Her father, the Baron de Breteuil, was a regular figure in the court of Louis XIV; her mother was the sister of the baron's aunt. It was a second marriage for the baron, and Emilie was the youngest of three children. Emilie's education in Latin and philosophy began early, and the status of her parents allowed her to get an education most young women—even women of her own rank—did not enjoy. She was also trained as a musician, a more common pursuit for aristocratic young women. Her study of mathematics was encouraged by a friend of the family, and it became the focus of her education. At the age of eighteen she married Florent Claude, Marquis du Châtelet-Lomont. He was then thirty years old, had an established military career, and came from a noble family of Lorraine. Apparently the marriage was one of propriety and convenience: the couple did not share many common interests and spent little time together while the marquis continued his rise in the French military. The union produced three children, two of whom survived past infancy. With her husband often away, du Châtelet had ample time to take a variety of lovers—a practice not at all unusual or even scandalous in the aristocratic circles of the Louis XIV era. However, these relationships were not merely sexual; often they provided du Châtelet the intellectual stimulation and encouragement her past and current family life did not offer. Among her lovers was the Duc de Richelieu, a godson of Louis XIV, who supported her in pursuing further research in both physics and mathematics. She enjoyed a long-lasting liaison (though scholars disagree on whether they were lovers) with Pierre Louis de Maupertuis, a prominent mathematician who tutored her in algebra and physics and introduced her to other major thinkers of the day. Maupertuis took du Châtelet, disguised as a man, to the café discussions that were the predecessors of the great intellectual salons of Paris; there she became part of the circle of scientists who would make up the Newtonian school of the French Academy. Du Châtelet met Voltaire in 1733, and by most accounts it was mutual love at first sight. When Voltaire was forced into exile following the publication of the Lettres philosophiques in 1734, he took refuge at one of the Marquis du Châtelet's estates at Cirey, going so far as to remodel a home belonging to his lover's husband to suit their planned experiments. (For his part, the marquis was pleased to have Voltaire's assistance in maintaining the old property.) Madame du Châtelet eventually joined him there, and they began a period of intense research and study that profoundly shaped both of their careers. Adherents of Newton's model of physics established Cirey as their center, and du Châtelet assisted in the production of more than one treatise on the subject. Francesco Algarotti wrote his Il Neutonianismo per la dame (1735) at Cirey with du Châtelet's help, and Voltaire openly acknowledged her leading role in producing his Eléments de la philosophie de Newton (1738), particularly the section on optics. Du Châtelet herself had been working on her own “Essai sur l'optique” (“Essay on Optics”) while Voltaire wrote his treatise on Newton, but it was never published and much of the manuscript was lost. In 1737 she secretly entered a competition sponsored by the Académie Royale des Sciences, which resulted in her Dissertation sur la nature et la propagation de feu (1744; Essay on the Nature of Fire). Though she did not win, through the influence of Voltaire her work was published along with the winners. She published in 1738 a “Lettre sur les elements de la philosophie de Newton” in the Journal des sçavans, in which she discussed Newton's theory of attraction and mentioned her forthcoming Institutions de physique, her meditation on Newtonian physics integrated with the metaphysics of the controversial philosopher Gottfried Wilhelm Leibniz. The work was published anonymously in 1740, but a former tutor of hers, Samuel Koenig, attempted to claim authorship, spreading a report that the work merely represented his teachings. Du Châtelet was compelled to defend herself, asking Maupertuis and other scientists to acknowledge that the ideas—which she had discussed with them prior to her time with Koening—were her own. Their support was lukewarm, despite their conviction of her authorship, a reflection of her marginal status as a woman scientist and possibly her much-disputed embrace of Leibnizian metaphysics, which was seen by many in the French Academy as a betrayal of Newtonian doctrine. Du Châtelet, however, continued to be an advocate of Newton, laboring over her translation of Newton's Principia Mathematica for many years, right up until her death. Those years at Cirey also saw du Châtelet translating Bernard Mandeville's very popular Fable of the Bees, working concomitantly with Voltaire on their commentaries on the Bible, and writing an essay on happiness, the posthumously published Discours sur le bonheur (1779; Discourse on Happiness). In 1748 du Châtelet met the Marquis de Saint-Lambert and began a new love affair. Biographers have been divided on whether du Châtelet betrayed Voltaire or the opposite: at the same time, Voltaire had begun his famously scandalous affair with his niece, Mlle Denis. Du Châtelet became pregnant with Saint-Lambert's child late in 1748, although Voltaire and du Châtelet continued living and working together during this time. Du Châtelet did not believe she would survive the birth of another child and began working feverishly on her translation of Newton, sleeping only a few hours a day. Her premonition proved correct. A daughter was born September 4, 1749, in Lunéville, in the palace of the exiled king of Poland, King Stanislaus, with Voltaire, Saint-Lambert, and the Marquis du Châtelet all in attendance. Du Châtelet died September 10 of puerperal fever; the child died a few days later. Du Châtelet's work on Newton remained unfinished but was sufficiently developed to allow posthumous publication, with a preface by Voltaire.
The centerpiece of du Châtelet's publishing career is her work on Newton, in both the Institutions de physique and the translation of his Principia Mathematica, published as Principes mathématiques de la philosophie naturelle (1758). Du Châtelet's understanding of Newtonian physics was unrivalled by most of her peers, and she planned the Institutions de physique to explain in greater detail what Voltaire (and she) had addressed in the Eléments de la philosophie de Newton. In the course of working on the Institutions, however, du Châtelet developed an interest in the work of Leibniz, beginning with his ideas on kinetic energy but eventually including his metaphysics. Her exposition of physics thus also sought to account for the issue of free will and the existence and scope of a deity or creator. Similarly, her translation of Newton's Principia went beyond a simple French rendering of Newton's writing. She included extensive commentary, additions, and corrections, incorporating the work of her friends Maupertuis, Alexis-Claude Clairaut, and Daniel Bernoulli. The work was praised for making Newton comprehensible to the larger scientific community and was a major victory for the Newtonians of the French Academy in advancing the popularity of Newton in France. Most of du Châtelet's other writings remained unpublished not only in her lifetime but even in the century following. The discovery of some lost manuscripts brought a handful of secondary, but still significant, works to light. Chief among these is her translation of Mandeville's Fable of the Bees, an English satire labeled by its author as “An Enquiry into the Origin of Moral Virtue.” Mandeville's work was a controversial success, widely read and widely denounced in England and Europe. Du Châtelet admired it greatly and considered it an important work on ethics. Her unpublished translation of the work employed a method similar to that which she would later use with Newton: she corrected and commented liberally, also omitting sections she found tedious, too “English,” too religious, or simply incorrect. She added her own thoughts on natural law, the passions, and the position of women. While her translation of Mandeville was not read during her lifetime, except among her peers, this work was quite familiar to Voltaire, who was strongly influenced by it in writing his own Traité de métaphysique. In keeping with philosophical trends of the day, she began a work on grammar, the unfinished Grammaire raisonné, and she applied her thoughts on deism and metaphysics to a study of the Bible, resulting in the unpublished Examen de la Genèse (which may be translated as “The Examination of Genesis”). Both studies reflect du Châtelet's Enlightenment commitment to applying science and reason to all aspects of human life, including language and religion. Her Discourse on Happiness, written around the time both Diderot and Voltaire were writing on the subject of happiness, also demonstrates her involvement in general Enlightenment trends of thought.. In these shorter works, du Châtelet wrote in the manner of the philosophes with whom she associated, at times adding a feminine perspective, such as the importance of allowing women to study. These works illuminate her larger career, though they figure chiefly as marginal notes in her remarkable achievements in advancing physics and mathematics in eighteenth-century France.
Du Châtelet was blessed with high standing in society, influential and intelligent friends, and access to publishers. While this did not entirely make up for the disadvantage of being born female, it went a long way in securing her at least some acceptance in the scientific and intellectual communities in which she moved. Voltaire was always unstinting in his praise of her intelligence; that he continued to study with her and speak highly of her after the break in their affair suggests that his was not merely the praise of an adoring lover. Upon the publication of her translation of Newton's Principia, she was widely acknowledged as one of France's foremost scholars on Newton. Her edition was said to be better than that of the original, and it remained the standard French translation of the work well into the twentieth century. Nonetheless, the sharp criticisms of du Châtelet as an unattractive and improper woman followed her into the twentieth century, with most biographers and critics focused on her love of gambling, her multiple lovers, and her relationship with Voltaire in particular. Two early biographies of the woman who championed Newtonian physics in France, Nancy Mitford's Voltaire in Love and Samuel Edward's The Divine Mistress, focus almost solely on her romantic relationships, as their titles suggest. As a result, many scholars tended to see du Châtelet as merely a mouthpiece for Voltaire and the other great men at Cirey. Much of the credit for the gradual reevaluation of du Châtelet's merits goes to Ira O. Wade, whose discovery of several missing manuscripts belonging to du Châtelet revealed the extent to which Voltaire and the others were truly in her debt. In his 1941 study, Voltaire and Madame du Châtelet, Wade asserted her independence as a thinker and her influence on Voltaire. Gradually Wade's view of her importance came to be more widely accepted, and critical assessments of her scientific work were less likely to see her as derivative or secondary to Voltaire. By the 1970s feminist scholars interested in recovering information about early women scientists began fully restoring her reputation, evaluating her work on its own merits. Linda Janik was among those emphasizing the originality of du Châtelet's work, while also acknowledging the limits placed on her learning as a woman. Both Janik and, later, Judith Zinsser discovered that du Châtelet appeared to negotiate those limits in a way that gave her greater social and intellectual freedom than most women—even women of rank—enjoyed. In Julie Hayes's study of reason and the French Enlightenment, du Châtelet's work stands next to that of Condillac and Diderot as an instance of the expression of a rational system. Hayes focused on du Châtelet's articulation of Newtonian physics and paid minimal attention to her famous male acquaintances. This type of examination fulfills what du Châtelet famously requested in a letter to her friend Prince Frederick of Prussia: “Judge me for my own merits or my lack of them but do not look upon me as an appendage to this great general or that renowned scholar. … I am in my own right a whole person, responsible to myself alone, for all that I am, all that I say, all that I do.”