Emilie du Châtelet’s Institutions de physique as a document in the history of French Newtonianism

No acount of the reception of Newtonian science in France would be complete without some mention of first French translator of Newton’s Principia mathematica, Gabrielle-Emilie le Tonnelier de Breteuil, Marquise du Châtelet. Completed in 1749, but not published until 1756/1759, Principes mathématiques de la philosophie naturelle par feue Madame la Marquise du Chastellet is a monument to female achievement in science and mathematics, justly celebrated in a recent article by Judith P. Zissner.¹ However, Madame du Châtelet’s translation of Newton was not her only contribution to the promotion of Newtonianism in Enlightenment France. Her translation represents the culmination of a process of engagement with Newton that can be traced through the last dozen years of her life. In this paper I propose to focus on an earlier stage of that process by examining another work, her Institutions de philosophie, in the context of her championship of Newton.

There is no doubt that Du Chatelet’s Principes mathématiques de la philosophie naturelle is the product of intense study of mathematics and deep understanding of Newtonianism. However, the significance of her translation for the fortunes of Newtonianism in France is less easy to assess, because, despite the acclaim of philosophes such as Diderot,² we cannot be sure that it played any significant role in mediating Newtonianism to the French public. To say this is not to undervalue the achievement of the translator, whose mathematical capabilities surpassed most of the leading male mathematical minds of her day. Nor do I mean to play down the role of translation in the dissemination of Newton’s thought—after all, it was through translation that Newton’s physics reached a wider public across Europe.³ But we have to recognise that Newton’s Principia mathematica was a work requiring such a high level of technical expertise, that the specialist readership equipped to understand it was probably also sufficiently educated in Latin to use either Newton’s original or the Jacquier edition. It is unlikely that there was a vernacular readership for a work of such advanced mathematics in the eighteenth century. The problem of accessibility was not lost on Madame du Châtelet herself who, when commending Voltaire’s Eléments de la philosophie de Newton to the rational reader (‘Lecteur raisonnable & attentif’), observed that Newton’s philosophy is too thick with calculations and algebra to be accessible to anyone but adepts:

Mais sa Philosophie hérisée de calculs & d’algèbre etoit une espece de mistere auquel les seuls initiés savoient droit de participer.⁴

In 1734 Madame du Châtelet had confessed to Maupertuis that she herself was not sufficiently proficient in algebra to follow his arguments (‘je ne sais pas assez d’algèbre pour avoir pu vous suivre partout’).⁵ She was no doubt mindful of the difficulties of communicating with a non-expert audience when she included with her translation of the Principia her Exposition abregée du Systéme du monde, designed, as Judith Zissner suggests, to render the work more accessible to French readers. Until more is known about the readership of her French translation, we have no means of assessing whether, if at all, Du Châtelet’s Principes played any significant role in mediating Newton to the French public, or whether it played any part in moulding the conceptualisation of Newtonianism in French.⁶ Meanwhile, there is much to learn about Madame du Châtelet’s contribution to the history of Newtonianism in France by focusing on the translator and her own writings, rather than on her translation. In this paper I shall begin that process by considering the other book that brought her fame, her Institutions de physique first published in Paris in 1740, nearly a decade before she completed her translation of Newton. The circumstances of production of the Institutions, its content and printing history suggest that the book was written as part of a Newtonian agenda and needs to be read in the context of the promotion of Newton by Voltaire and others. Considered as part of an on going debate about Newton, rather than a definitive statement of the author’s Newtonianism, the book deserves be treated as a document of Du Châtelet’s study of Newton and of her promotion of Newton’s physics in France. Historical documents, however, do not speak for themselves, but need interpretation. And interpretation requires context. By exploring links between the content of the book and Du Châtelet’s milieu, I shall attempt to position the book in relation to the French reception of Newton. My intention is not to provide an exhaustive analysis of the book or the ongoing debates about Newtonianism that it reflects. But I hope this will prepare the ground for further study.