Early Life

(17th- and 18th-Century Biographies)

0111200108-Alembert.jpg Jean le Rond d’Alembert (Library of Congress) Published by Salem Press, Inc.

On the night of November 17, 1717, Mme Claudine-Alexandrine Guérin, Marquise de Tencin, gave birth to a son whom she promptly abandoned on the steps of the Church of Saint-Jean-Le-Rond. There, he was baptized with the name of the church; he was then sent to the Maison de la Coucher, from which he went to a foster home in Picardy. When his father, Louis-Camus Destouches, a military officer, returned to Paris, he sought his son and arranged for the child to be cared for by Mme Rousseau, the wife of a glazier. D’Alembert would always regard Mme Rousseau as his real mother and would continue to live with her until 1765, when illness compelled him to seek new quarters in the home of Julie de Lespinasse.

Destouches continued to watch over his illegitimate child, sending him to private schools; when Destouches died in 1726, he left the boy a legacy of twelve hundred livres a year. The sum, though not luxurious, guaranteed him an independence he cherished throughout his life. Through the interest of the Destouches family, the young man entered the Jansenist Collège des Quatre-Nations, where he took the name Jean-Baptiste Daremberg, later changing it, perhaps for euphony, to d’Alembert. Although he, like many other Enlightenment figures, abandoned the religious training he received there, he never shed the Cartesian influence that dominated the school.

After receiving his baccalauréat in 1735, he spent two years studying law, receiving a license to practice in 1738. Neither jurisprudence nor medicine, to which he devoted a year, held his interest. He turned to mathematics, for which he had a natural talent. At the age of twenty-two, he submitted his first paper to the Académie des Sciences; in that piece, he corrected a number of errors in Father Charles Reyneau’s Analyse demontrée (1714). A second paper, on refraction and fluid mechanics, followed the next year, and in May, 1741, he was made an adjunct member of the Académie des Sciences.

Life’s Work

(17th- and 18th-Century Biographies)

Two years later, d’Alembert published a major contribution to mechanics, Traité de dynamique (1743), which includes his famous principle stating that the force which acts on a body in a system is the sum of the forces within the system restraining it and the external forces acting on that system. Although Sir Isaac Newton and Johann Bernoulli had already offered similar observations, neither had expressed the matter so simply. The effect of d’Alembert’s principle was to convert a problem of dynamics to one of statics, making it easier to solve. The treatise is characteristic of d’Alembert’s work in several ways: It illustrates his exceptional facility with mathematics; it reveals a desire to find universal laws in a discipline; and it indicates his ability to reduce complex matters to simple components. Over the next several years, he wrote a number of other innovative works in both mathematics and fluid mechanics.

At the same time that d’Alembert was establishing himself as one of Europe’s leading mathematicians—in 1752 Frederick the Great offered him the presidency of the Berlin Academy—he emerged as a leading figure of the Parisian salons. In 1743, he was introduced to the influential Mme du Deffand, who would secure his election to the Académie Française in 1754. He remained a fixture of her assemblies until Julie de Lespinasse, whom he met there, established her own salon following a quarrel with the older woman. Later in the 1740’s, he also joined the gatherings at the homes of Mme Marie-Thérèse Rodet Geoffrin and Anne-Louise Bénédicte de Bourbon, Duchesse du Maine. Not striking in appearance—he was short and, according to a contemporary, “of rather undistinguished features, with a fresh complexion that tends to ruddiness,” his eyes small and his mouth large—he compensated for his looks with his excellent ability with mimicry and his lively conversation.

While enjoying the female-dominated world of the salons, d’Alembert was also meeting a number of important male intellectuals, with whom he dined weekly at the Hôtel du Panier Fleuri—Denis Diderot, Jean-Jacques Rousseau (no relation to his stepmother), and Étienne Bonnot de Condillac. He probably also knew Gua de Malves, a fellow mathematician and member of the Académie des Sciences, who was chosen as the first editor of the Encyclopédie (1751-1772), and Malves may have been the one who introduced d’Alembert to the project; after Malves resigned, d’Alembert was named coeditor with Diderot.

D’Alembert did not plan to assume as much responsibility for the work as his coeditor. He wrote to Samuel Formey in September, 1749:

I never intended to have a hand in [the Encyclopédie] except for what has to do with mathematics and physical astronomy. I am in a position to do only that, and besides, I do not intend to condemn myself for ten years to the tedium of seven or eight folios.

It was Diderot who conceived of the work as a summation of human knowledge, but d’Alembert’s involvement extended well beyond the mathematical articles that the title page credits to him.

His contributions took many forms. He used his scientific contacts to solicit articles, and his connection with the world of the salons, which Diderot did not frequent, permitted him to enlist support among the aristocracy and upper middle class. Not only was such backing politically important, given the controversial nature of the enterprise, but also the financial assistance d’Alembert secured may well have prevented its collapse. Mme Geoffrin alone is reported to have donated more than 100,000 livres.

Also significant are the fifteen hundred articles...

(The entire section is 1522 words.)


(17th- and 18th-Century Biographies)

Cassirer, Ernst. The Philosophy of the Enlightenment. Translated by Fritz A. C. Koelln and James P. Pettegrove. Princeton, N.J.: Princeton University Press, 1951. This work explores the way the Enlightenment looked at nature, psychology, religion, history, society, and aesthetics. Much, inter alia, about d’Alembert.

Essar, Dennis F. The Language Theory, Epistemology, and Aesthetics of Jean Lerond d’Alembert. Oxford, England: Voltaire Foundation at the Taylor Institution, 1976. A study of d’Alembert’s philosophy. Argues that d’Alembert’s “position in the Enlightenment remains of central, pivotal importance.” Also treats d’Alembert’s mathematical and scientific contributions.

Grimsley, Ronald. Jean d’Alembert, 1717-83. Oxford, England: Clarendon Press, 1963. A topical study of d’Alembert’s contributions to the Encyclopédie, his relations with other philosophers, and his own views. Largely ignores the scientific and mathematical aspects of d’Alembert’s career.

Hankins, Thomas L. Jean d’Alembert: Science and the Enlightenment. Oxford, England: Clarendon Press, 1970. An ideal complement to Grimsley’s book, for it concentrates on the science and the mathematics. Relates d’Alembert’s achievements to those of other scientists and the role of science to that of philosophy in the eighteenth century.

Pappas, John Nicholas. Voltaire and d’Alembert. Bloomington: Indiana University Press, 1962. Drawing heavily on the correspondence between the two, this study seeks to rectify the view, fostered in large part by Voltaire, that d’Alembert was a hesitant follower of the older intellectual. Notes that the influence was mutual and shows where the two differed.

Van Treese, Glen Joseph. D’Alembert and Frederick the Great: A Study of Their Relationship. New York: Learned Publications, 1974. Treats the origin, nature, and consequences of the friendship between d’Alembert and the Prussian ruler. Offers a portrait of the two men and of their age.