Émilie du Châtelet

Gabrielle Émilie Le Tonnelier de Breteuil, Marquise du Châtelet (French: [emili dy ʃɑtlɛ] ; 17 December 1706 – 10 September 1749) was a French mathematician and physicist.

Her most recognized achievement is her philosophical magnum opus, Institutions de Physique (Paris, 1740, first edition; Foundations of Physics). She then revised the text substantially for a second edition with the slightly modified title Institutions physiques (Paris, 1742). It circulated widely, generated heated debates, and was translated into German and Italian in 1743. The Institutions covers a wide range of topics, including the principles of knowledge, the existence of God, hypotheses, space, time, matter and the forces of nature. Several chapters treat Newton's theory of universal gravity and associated phenomena. Later in life, she translated into French, and wrote an extensive commentary on, Isaac Newton's Philosophiæ Naturalis Principia Mathematica. The text, published posthumously in 1756, is still considered the standard French translation to this day.

Du Châtelet participated in the famous vis viva debate, concerning the best way to measure the force of a body and the best means of thinking about conservation principles. Posthumously, her ideas were represented prominently in the most famous text of the French Enlightenment, the Encyclopédie of Denis Diderot and Jean le Rond d'Alembert, first published shortly after du Châtelet's death.

She is also known as the intellectual collaborator with and romantic partner of Voltaire. In the two centuries since her death, numerous biographies, books, and plays have been written about her life and work. In the early twenty-first century, her life and ideas have generated renewed interest.

Contribution to philosophy

Du Châtelet wrote a number of significant scientific and philosophical works, including an essay on the nature of fire which was published by the Royal Academy of Sciences in Paris, as well as her magnum opus, the Institutions de physique, which was also translated into German and Italian. In addition to her original works, Du Châtelet also produced influential translations of major works by authors such as Bernard Mandeville and Isaac Newton.

Because of her well-known collaboration and romantic involvement with Voltaire that spanned much of her adult life, her accomplishments have often been subsumed under his, and historical accounts have often mentioned her only within the context of Voltaire's life and work during the period of the early French Enlightenment. However, the nature of their relationship was collaborative. Voltaire acknowledged that du Châtelet's mathematical expertise was a crucial aid in understanding the technical parts of Newton's Principia while writing his popularization of the Newtonian philosophy, Éléments de la philosophie de Newton.

Recently, scholars have taken a renewed interest in du Châtelet, which has resulted in a renewed appreciation of her original contributions. Historical evidence indicates that her work had a very significant influence on the philosophical and scientific conversations of the 1730s and 1740s – in fact, she was famous and respected by the greatest thinkers of her time. Francesco Algarotti styled the dialogue of Il Newtonianismo per le dame based on conversations he observed between du Châtelet and Voltaire at Cirey.

Du Châtelet corresponded with the renowned mathematicians Johann II Bernoulli and Leonhard Euler, early developers of calculus. She was also tutored by Bernoulli's prodigy students, Pierre Louis Moreau de Maupertuis and Alexis Claude Clairaut. Frederick the Great of Prussia, who re-founded the Academy of Sciences in Berlin, was her great admirer, and corresponded with both Voltaire and du Châtelet regularly. He introduced du Châtelet to Leibniz's philosophy by sending her the works of Christian Wolff, and du Châtelet sent him a copy of her Institutions.

Her works were published and republished in Paris, London, and Amsterdam; they were translated into German and Italian; and, they were discussed in the most important scholarly journals of the era, including the Memoires des Trévoux, the Journal des Sçavans, the Göttingische Zeitungen von gelehrten Sachen, and others.

Many of her ideas were represented in various sections of the Encyclopédie of Diderot and D'Alembert, and some of the articles in the Encyclopédie are a direct copy of her work.

Biography

Early life

Émilie du Châtelet was born on 17 December 1706 in Paris, the only daughter amongst six children. Three brothers lived to adulthood: René-Alexandre Le Tonnelier de Breteuil (1698–1720), Charles-Auguste Le Tonnelier de Breteuil (1701–1731) and abbot Elisabeth-Théodore Le Tonnelier de Breteuil (1710–1781). Her eldest brother, René-Alexandre, died in 1720, and the next brother, Charles-Auguste, died in 1731. However, her younger brother, Elisabeth-Théodore, lived to a successful old age, becoming an abbot and eventually a bishop. Two other brothers died very young. Du Châtelet also had a half-sister, Michelle, born in 1686, of her father and Anne Bellinzani, an intelligent woman who was interested in astronomy and married to an important Parisian official.

Her father was Louis Nicolas le Tonnelier de Breteuil (1648–1728), a member of the lesser nobility. At the time of du Châtelet's birth, her father held the position of the Principal Secretary and Introducer of Ambassadors to King Louis XIV. He held a weekly salon on Thursdays, to which well-respected writers and scientists were invited. Her mother was Gabrielle Anne de Froulay (1670–1740), Baronne de Breteuil and daughter of soldier Charles de Froulay (1601–1671). Her paternal grandfather was administrator Louis Le Tonnelier de Breteuil (1609–1685). Her paternal uncle was cleric Claude Le Tonnelier de Breteuil (1644–1698). Among her cousins was nobleman François Victor Le Tonnelier de Breteuil (1686–1743), son of her uncle François Le Tonnelier de Breteuil (1638–1705). Among her nephews was aristocrat, diplomat and statesman Louis Auguste Le Tonnelier de Breteuil (1730–1807).

Early education

Du Châtelet's education has been the subject of much speculation, and nothing is known with certainty.

Among their acquaintances was Fontenelle, the perpetual secretary of the French Académie des Sciences. Du Châtelet's father Louis-Nicolas, recognizing her early brilliance, arranged for Fontenelle to visit and talk about astronomy with her when she was 10 years old. Her mother, Gabrielle-Anne de Froulay, had been brought up in a convent, which was at that time the predominant educational institution available to French girls and women. While some sources believe her mother did not approve of her intelligent daughter, or of her husband's encouragement of Émilie's intellectual curiosity, there are also other indications that her mother not only approved of du Châtelet's early education, but actually encouraged her to vigorously question stated fact.

In either case, such encouragement would have been seen as unusual for parents of their time and status. When she was small, her father arranged training for her in physical activities such as fencing and riding, and as she grew older, he brought tutors to the house for her. As a result, by the age of twelve she was fluent in Latin, Italian, Greek and German; she was later to publish translations into French of Greek and Latin plays and philosophy. She received education in mathematics, literature, and science.

Du Châtelet also liked to dance, was a passable performer on the harpsichord, sang opera, and was an amateur actress. As a teenager, short of money for books, she used her mathematical skills to devise highly successful strategies for gambling.

Marriage

On 12 June 1725, she married the Marquis Florent-Claude du Chastellet-Lomont (1695–1765). Her marriage conferred the title of Marquise du Chastellet. Like many marriages among the nobility, theirs was arranged. As a wedding gift, her husband was made governor of Semur-en-Auxois in Burgundy by his father; the recently married couple moved there at the end of September 1725. Du Châtelet was eighteen at the time, her husband thirty-four.

Émilie du Châtelet and the Marquis Florent-Claude du Chastellet-Lomont had three children: Françoise-Gabrielle-Pauline (1726–1754), married in 1743 to Alfonso Carafa, Duca di Montenero (1713–1760), Louis Marie Florent (1727–1793), and Victor-Esprit (1733–1734). Victor-Esprit died as an infant in late summer 1734, likely the last Sunday in August. On 4 September 1749 Émilie du Châtelet gave birth to Stanislas-Adélaïde du Châtelet, daughter of Jean François de Saint-Lambert. She died as a toddler in Lunéville on 6 May 1751.