Please note: All files marked with a copyright notice are subject to normal copyright restrictions. These files may, however, be downloaded for personal use. Electronically distributed texts may easily be corrupted, deliberately or by technical causes. When you base other works on such texts, double-check with a printed source if possible.

Jean Le Rond d'Alembert
A brief presentation, by Karl-Erik Tallmo

  Jean Le Rond d'Alembert, mathematician, philosopher, and writer, was one in the group of French intellectuals, the so called Encyclopaedists, who edited the famous ”Encyclopédie, ou Dictionnaire raisonné des sciences, des arts et des métiers”. This circle also included enlightened men of letters like Diderot, Voltaire, Montesquieu, and Rousseau.

Being the illegitimate son of Mme de Tencin, hostess of one of Paris’ many famous salons, d’Alembert was left on the steps to the church Saint-Jean-le-Rond. He was, however, later adopted by a glazier’s wife, whom d’Alembert from then on regarded as his real mother.

Jean Le Rond d’Alembert (1717-1783)

Already as a young man he had acquired a considerable appetite for knowledge, and he devoted his time to the study of theology and law, but very soon these subjects were abondoned in favour of mathematics and physics. He became a member of the Académie des Sciences, only 24 years old. Within this field, he is well-known for his particularizing av Newton’s theories about actions creating counter-reactions, d’Alembert’s principle.  He also made calculations concerning vibrating strings and their oscillating frequences, published in ”Recherches sur les cordes vibrantes” (1747).

Eventually he came into the circles around Diderot and the other Encyclopaedists. They are not to be regarded as some sort of homogenous political or philosophical movement in the modern sense, but rather as a group of individuals with a few common goals and aspirations. There were some discord and antagonism within the group. For instance, d’Alembert felt he had to dissociate himself from Rousseau, whose hostility towards civilization was incompatible with the other Encyclopaedists’ optimist view upon rationalism and progress.

The Encyclopaedia was edited very much in the spirit of Locke, Bacon, Newton, and Descartes. Diderot wrote the most part, Montesquieu discussed political matters, Rousseau dealt with music, and d’Alembert wrote about mathematics and physics - and, of course, he was the author of the famous epistemological preface, the Discours préliminaire.  In the background we may discern highly influential works, such as Locke’s ”An Essay Concerning Human Understanding” and, from a more lexicographical view-point, Ephraim Chambers ”Cyclopedia or An Universal Dictionary of Arts and Sciences” (1728).

”A man cannot conceive himself capable of a greater certainty than to know that any idea in his mind is such as he perceives it to be,” wrote Locke in his Essay in 1690. ”Rien n’est plus incontestable que l’existence de nos sensations”, wrote d’Alembert in 1751. (And ”Nothing can be more certain, than that the idea  we receive from an external object is in our minds”, is what Encyclopaedia Britannica was to say on this subject in 1771.)

The relationship between our perceptions and knowledge is, of course, the crux of the matter. Is there any point at all in our trying to achieve knowledge? But this question soon turns itself into a question of language. It was convenient for a well-arranged philosophy like this, to also include a rather simplified view upon the relationship between ideas, concepts and words, ”there are few sciences and arts, whose theses cannot be reduced to simple ideas and arranged with one another in such an immediate order that the chain will hold together all the way”,1  d’Alembert says, and a little further on he continues, ” since good facilities for rendering and receiving ideas through mutual exchange also result in indisputable advantages, it is not surprising that people more and more tried to develop these possibilities. For that purpose they started to reduce the signs to words, since words are the symbols that are easiest to handle. ”2

Consequently, the appearance of language was the result of deliberate decisions, yet another highly rational invention made by humans. And also Locke wrote, ”Words become general by being made the signs of general ideas: and ideas become general, by separating from them the circumstances of time and place, and any other ideas that may determine them to this or that particular existence.”3

All ideas are interrelated, maybe not immediately, but if you trace them back long enough, you will find a common stem. The Encyclopaedist must place himself on a high outlook, to get a good overview of the labyrinth and see how the most important arts and sciences diverge and converge.

The title page of the first volume of the Encyclopaedia.

What happned when the Encyclopaedia was published? The first volume came in July 1751, and it was printed in 2 050 copies. Most people were exalted about the Encyclopaedia's message about reason, free speech and the popularizing of the sciences. Of course, certain conservatives found the content heretical, so when volume two arrived it was confiscated, and Diderot was forced underground. The course of publication went on, however, until 1772, when all of the 28 volumes had been printed. Already in 1754 had d’Alembert become a member of the Académie française, to a large part probably thanks to Mme du Deffand, protectress of many authors, also of those who, like d’Alembert, preached ”liberty, truth, and poverty” as the foremost virtues of a writer.

d’Alembert got several tempting offers from abroad, for instance from Catherine II of Russia and Frederick II of Prussia to come and work in their countries, but he chose to stay with the Paris intellectuals. He died in 1783, almost 66 years old.


1. ”[...] il n'y a presque point de science ou d'art dont on ne pût à la rigueur, et avec une bonne logique, instruire l'esprit le plus borné; parce qu'il y en a peu dont les propositions ou les règles ne puissent être réduites à des notions simples, et disposées entre elles dans un ordre si immédiat, que la chaîne ne se trouve nulle part interrompue.” (Discours préliminaire,  first part)

2. ”Cependant la facilité de rendre et de recevoir des idées par un commerce mutuel ayant aussi de son côté des avantages incontestables, il n'est pas surprenant que les hommes aient cherché de plus en plus à augmenter cette facilité. Pour cela ils ont commencé par réduire les signes aux mots, parce qu'ils sont, pour ainsi dire, les symboles que l'on a le plus aisément sous la main. ” (Discours préliminaire,  first part)

3. An Essay Concerning Human Understanding,  Book III, Chapter III, par. 6. (The Essay is hopefully still available on the Net, either here or here.)

First part; première partie

Second part; Deuxième partie

[English Homepage]
[Svensk bassida]
[Origo menu]