Translator’s Introduction to the Preliminary Discourse

Originally published in Jean le Rond d'Alembert, Preliminary Discourse to the Encyclopedia of Diderot, trans. Richard N. Schwab with the collaboration of Walter E. Rex (Chicago: University of Chicago Press, 1995), ix-lii. Used with permission.    Cite online version (MLA or Chicago)

Richard N. Schwab

In a word, Madame, I can assure you that while writing this work, I had posterity before my eyes at every line.

d’Alembert to Madame du Deffand, December 22, 1752.

Of all the shorter works of the eighteenth-century philosophes, the Preliminary Discourse to Diderot’s Encyclopedia is incomparably the best introduction to the French Enlightenment.[1] It is the Enlightenment insofar as one can make such a claim for any single work; with a notable economy and vigor it expresses the hopes, the dogmas, the assumptions, and the prejudices we have come to associate with the movement of the philosophes. From the moment of its publication in 1751, many leaders of the Enlightenment recognized it as a masterful statement of their “philosophy,” and even the men who were fearful of its implications acclaimed it for its lucidity and compactness. No less a judge than the great Montesquieu complimented d’Alembert on his work in the most flattering terms: “You have given me great pleasure. I have read and reread your Preliminary Discourse. It has strength, it has charm, it has precision; richer in thoughts than in words, likewise rich in sentiment—and my praises might go on.”[2] Frederick the Great ranked it above his grandest military accomplishments: “Many men have won battles and conquered provinces,” he wrote, “but few have written a work as perfect as the preface to the Encyclopedia.[3] Toward the end of the century Condorcet eloquently summed up the judgment of the work shared by a substantial proportion of his fellow philosophes: “The union of a vast extent of knowledge, that manner of viewing the sciences which belongs only to a man of genius, a clear, noble, and energetic style, having all the severity which the subject demands and all the pungency that it permits, have placed the Preliminary Discourse of the Encyclopedia in the number of invaluable works which two or three at the most in each century are in a position to execute.”[4] Ever since the eighteenth century the Discourse has been cited repeatedly as the most representative work of its age.[5]

Indeed, the Preliminary Discourse could be regarded as the manifesto of the French Enlightenment, at least in the retrospective view of the historian. To be sure, it was not designed to be a pronouncement heralding or justifying revolutionary political action as were the Declaration of Independence, the Declaration of the Rights of Man, and the Communist Manifesto, but it expressed the spirit of an intellectual and emotional revolution going on in the eighteenth century that in one way or another lay in the background of each of these. It breathed a confidence that man, through his own intelligent efforts, could transform the conditions of human life and that the beginning of that revolution could already be seen in the sciences and arts.

Compared with anything that had preceded it, the Discourse was unique. We have seen its likes since, but one looks in vain throughout previous history for a declaration of principles that represented, as this one did, the views of a party of men of letters who were convinced that through their combined efforts they could substantially contribute to the progress of humanity. Francis Bacon (1561–1626) dreamed of the co-operation of scholars for the advancement of learning, but he had no grounds for hoping that his schemes might soon revolutionize society. His New Atlantis was a distant utopia. Descartes (1596–1650) wrote as a courageous, lone individual, seeking truth through the powers of his isolated intelligence, although he of course understood that the advance of knowledge depended on the mutual efforts of scholars. He spoke for himself in the Discourse on Method, and not for a group of men of letters. The scholarly societies of the seventeenth and early eighteenth centuries, while hoping to contribute to material progress, were concerned primarily with the erudite and professional activities of closeted savants and did not dream of transforming the conditions of the world in a fundamental way.

However, by the end of the seventeenth century, the members of the European international republic of letters were developing an awareness that cumulatively they were a force in the world, and this birth of a self-conscious sense of power among the literati proved to be one of the revolutionary events of modern times. For the first time large numbers of people were coming to the bracing conclusion that the progress of humanity could be carried forward indefinitely in this world, and men of letters felt they were the prime movers of that progress. Rather than isolating themselves in their closets, certain scholars and writers conceived of themselves as being very much involved in the affairs of the world and believed that their intellectual activity, if it contributed to the progress of knowledge, inevitably served a social function. A capital feature of the great Encyclopedia of Diderot, for which the Preliminary Discourse was the introduction, was that it became the principal expression of the solidarity and power of that group of energetic and articulate men of letters in France.

As the focal point of the French Enlightenment, the encyclopedic project marked a critical step in the process by which intellectual forces and an ever more influential portion of the French public combined in demanding reform. We now view the Encyclopedia more as a major historical event than as an original contribution to any of the branches of knowledge. Its publication precipitated a prolonged controversy that clarified the positions of various amorphous factions in the intellectual and emotional world of the eighteenth century and squarely confronted them with one another. Those who ranged themselves on the side of the encyclopedists in effect formed a party, or the rudiments of one, which served as the spiritual predecessor for groups of reformers who were to preside in large measure over the transformation of the conditions of life in France and throughout the western world during the next generation. Thus, as the most perfect expression of the principles of the encyclopedists and their sympathizers, the Preliminary Discourse can be singled out by the historian as the manifesto of the Enlightenment in a fuller sense, perhaps, than d’Alembert or his colleagues might originally have intended it to be.

The Background of the Discourse

The Preliminary Discourse was the work of a young scholar, in association with other men of letters who were not quite angry but were filled with an iconoclastic gusto and a confident dedication to what they felt were great and progressive ideas. Their engaging characters, their colorful and earthy eccentricities growing from an eighteenth-century atmosphere especially conducive to individuality and originality, give a special appeal to the study of that era. The twentieth-century reader is surprised by the degree of compactness and intimacy of the lively universe that existed in Europe just before the vast mushrooming of population during the past two centuries. A very large percentage of the men of letters knew one another well enough to be great friends or to hate one another. The most able of them in France easily gravitated together in Paris. Thus it was possible that in the second half of the 1740’s the possessors of perhaps the four best young minds in the realm knew one another and perhaps on occasion even argued, jested, and pontificated around the same table. These were Diderot, the Genevan Rousseau, Condillac, and d’Alembert. Rousseau recalled episodes of their early association during the years before 1750 in his Confessions. Diderot, he wrote, became his intimate friend, with whom he had practically daily contact.

I had also begun to see a good deal of the abbé de Condillac who was, like myself, of no consequence in the literary world, but was destined to become what he is at the present day. I was perhaps the first who recognized his ability and saw his true worth. He seemed likewise to take pleasure in my company, and, while I was shut up in my room in the rue Jean-Saint-Denis, near the Opéra, . . . he would sometimes come to eat his supper informally along with me, just the two of us. He was then working on his Essay Concerning the Origin of Human Knowledge [1746], his first work. When it was completed the problem was to find a publisher willing to accept it. Paris publishers are always arrogant and harsh toward someone who is just beginning, and metaphysics, which was not very fashionable then, hardly seemed an enticing subject. I spoke to Diderot of Condillac and his work and introduced them to one another. They were made to suit each other, and so they did. Diderot induced Durand[6] the publisher to accept the abbé’s manuscript, and for his first book this great metaphysician earned—and that almost as a favor—a hundred livres, which he might not have received without me. As we lived in quarters that were widely separated, all three of us met once a week at the Palais-Royal, and we dined together at the hôtel du Panier Fleuri. These little weekly dinners must have been very much to Diderot’s liking, for he, who nearly always failed to keep his appointments, never missed one of them. There I drew up the plan of a periodical called Le Persifleur, to be written alternately by Diderot and myself. I sketched out the first number, and this brought about my acquaintance with d’Alembert, to whom Diderot had spoken of it. Then unforeseen events got in our way, and this plan went no further.
These two authors had just undertaken the Dictionnaire Encyclopédique, which at first was only intended to be a kind of translation of Chambers, somewhat like that of James’ Dictionary of Medicine, which Diderot had just finished. He wanted me to have some part in this second enterprise, and proposed that I should undertake the musical section of it. I consented, and executed it very hastily and poorly in the three months he had stipulated to me as well as all the others who were to collaborate in the work. But I was the only one who was ready at the prescribed time. I gave him my manuscript, of which I had had a fair copy made by one of M. de Fancueil’s lackeys, named Dupont, who wrote very well, paying him ten livres out of my own pocket, for which I have never been reimbursed. Diderot, on the part of the publishers, promised me some remuneration, a remuneration of which he has never spoken to me again—nor have I to him.[7]

At the time of the composition and publication of Diderot’s Prospectus for the Encyclopedia (1750) and of the Preliminary Discourse (1751), these men, all in their thirties, were just beginning their careers. They belonged to the second generation of the philosophes. The time came when they were lionized and wooed by the crowned heads of Europe and the influential in society as the foremost intellectual attractions of France; but these were perhaps their happier days of relative obscurity.

Jean Le Rond d’Alembert (1717–1783), although he was the youngest of the four, was best known for some time because of his precocious scientific and mathematical genius. By the time he joined the encyclopedic group he had already begun to make the contributions in those fields that were to assure him a permanent and important place in the history of science. His origins were bizarre. He was the natural son of a soldier aristocrat, the chevalier Destouches, and Madame de Tencin, one of the most notorious and fascinating aristocratic women of the century. A renegade nun, she acquired a fortune as mistress to the powerful minister, Cardinal Dubois, and after a successful career of political scheming, she rounded out her life by establishing a salon which attracted the most brilliant writers and philosophers of France. It is reported that d’Alembert was not the first of the inconvenient offspring she abandoned. In any case, he was found shortly after his birth on the steps of the Parisian church of Saint-Jean-Lerond. He was raised by a humble nurse, Madame Rousseau, whom he treated as his mother and with whom he lived until long after he achieved international fame. His father, the chevalier Destouches, was able to keep track of the boy and provided him with sufficient means for his schooling. While d’Alembert was yet a child he showed extraordinary promise which matured into genius. For a number of years the young scholar abandoned himself entirely to his passion for the physico-mathematical sciences and, largely without formal training, he succeeded in mastering these fields. At the age of twenty-six he published his Treatise on Dynamics (1743), now considered a landmark in the history of Newtonian mechanics, and he continued to contribute significantly to mathematics, astronomy, and dynamics through the period of his greatest scientific productivity in the 1740’s and early 1750’s. During most of his life he was in intimate contact with the eminent scientists of his day through his correspondence, and as a member of the most distinguished scientific societies of Europe.

D’Alembert’s gay and lively character, which shines forth in the famous smiling pastel of him by La Tour in 1753, his enthusiasm, and his brilliance won him the friendship of Diderot and several other excellent Parisian men of letters in the 1740’s. At the same time he charmed his way into the center of the powerful salon of Madame du Deffand, who became his intimate friend and protectress. The publication of the Preliminary Discourse brought him out of his obscurity as a poverty-stricken mathematician and launched him, in the public mind, as a philosophe. He began to be considered a spokesman for the philosophic party, a role which he adopted with great gusto. Endowed with an inquiring and facile intelligence, he easily assimilated the most exciting ideas of the time. His collected works included essays on a remarkable range of subjects. Along with Diderot and Rousseau, he was fascinated by the musical theories of Rameau, as will be seen in the Discourse. His Élémens de musique (1752), based on the principles of Rameau, was an influential work throughout Europe, and has caused music historians to rate him as one of the leading music critics of his century.[8] A combination of virtuosity, ambition, aggressiveness, and personal charm eventually won him a most honored position in the intellectual community of Europe. Among other rewards, it brought him the lasting friendship of both Voltaire and Frederick the Great, who engaged with him in a rich correspondence which lasted from the 1750’s throughout the remainder of their lives. Fairly early in his career he was elected to the most important academies of Europe. By the time he joined Diderot as an encyclopedist he was deeply involved in the active and inventive world of the French Academy of Sciences, and that connection was a valuable asset for the encyclopedic project. His entry into the Académie Française in 1754 marked a major victory for the encyclopedic party. Eventually he became the perpetual secretary of that academy, where he followed the tradition of composing eulogies that had been established by Fontenelle when he was secretary of the Academy of Sciences.

Like Diderot and Rousseau, d’Alembert was an emotional man, and as the years passed he became progressively more irascible, even malevolent on occasion. Straitened circumstances and inclination made him abstemious in his habits, and he never married. However, after 1754 he became the intimate friend of an aristocratic lady likewise of illegitimate birth, the famous Julie de Lespinasse, with whom he was ever more closely bound until her death left him desolate in 1776. Their strictly spiritual and intellectual relationship, which was something exceptional among the philosophes, filled an important chapter of the later part of his life, and together the two friends made a valuable contribution to the vitality of the reforming salons in the period after 1760.

D’Alembert may well have been introduced into his philosophic career by Diderot (1713–1784), with whom he was more intimately allied than with Condillac or Rousseau. Diderot possessed one of the most fascinating intellects of his time, and was, incidentally, one of its great conversationalists. Brilliant, demonstrative, sentimental, endlessly energetic and productive, he was capable of deluging his listener with a flood of surprising and original reflections on almost anything with which his mind grappled. Those around him found themselves hypnotized by his enthusiasm. The son of a cutler from Langres, he had come to Paris as a student and turned to living by his wits as a copyist, translator, and writer. From the outset, it would seem, his tastes were encyclopedic. Among his early productions was a pornographic book, Les Bijoux indiscrets (1748), which, judging by the number of editions it has gone through, has turned out to be his most popular work even to this century; but he was also beginning his career as a “philosophical writer” on many subjects that were dangerous to approach in France in the mid-eighteenth century. During his harried life he dashed off works in an astounding variety of subjects and genres: translations, novels, plays, philosophy, scientific theory, psychology, music and drama criticism, social criticism, and polemic. To the chagrin of his friends and the publishers, he was imprisoned in 1749 for some of his unorthodox writings at a time when he very much needed to be free so that he could carry out his multitude of duties as chief editor of the Encyclopedia.[9] D’Alembert, by his own account, was preoccupied exclusively with mathematics and physics until about the time he came to know Diderot. Then in the middle 1740’s he began to move in the circle of the philosophes and to convert himself into one of their number, doubtless carried along by the enthusiasms of the men around Diderot.

Jean-Jacques Rousseau (1712–1778) was one of the most extraordinary members of this group. He was a runaway vagabond from Geneva who in 1750 was on the point of becoming a great celebrity in the intellectual world. Passionately fond of music and, like d’Alembert and Diderot, a partisan of the theories of Rameau, he had become a composer himself, as well as the inventor of a new system of musical notation which he had tried to promote in Paris. He and d’Alembert collaborated on the musical articles for the Encyclopedia, although Rousseau wrote the bulk of them. He eked out a bare existence as a tutor. Wherever he went he attracted a lively group of companions, but his highly excitable and sensitive soul bore the seeds of a mental disorder which later resulted in a tormented and pathological rupture with many of his old friends, including Diderot and d’Alembert. Rousseau ultimately had a larger personal effect than any of his acquaintances upon the intellectual, emotional, and revolutionary history of Europe, and his career offers one of the best examples of the new impact of the intellectual classes upon the course of history. His democratic political theory became gospel in the political and social revolutions that lay ahead, and his approach to morality, sentiment, and emotion in his novels and other writings lies at the foundation of nineteenth-century Romanticism. However, in 1750 he had only begun to win his first public acclaim in the areas of ethical speculation for which he became famous. In that year he published his Discourse on the Sciences and the Arts, which was a subject of comment in the Preliminary Discourse. How much Rousseau’s interest in social speculation helped turn d’Alembert’s mind to the same subjects at the time he was writing the Preliminary Discourse we do not know. We may conjecture that all the men in that group of literary acquaintances earnestly discussed such matters and thus had their direct and indirect effects upon one another’s thought.

There is no doubt of the effect of the ideas of the abbé de Condillac (1715–1780) upon d’Alembert in the early stages of his intellectual career and later. Condillac was one of a company of men in Paris and elsewhere in France who held the clerical title “abbé.” In most cases the title merely signified an intention to become a priest, and it was conferred in a simple ceremony, often when the person who received it was still a child. A substantial share of those who had the title never took holy orders, which would have made them priests. With no real churchly functions, a crowd of abbés converged upon Paris, where many of them graced the households of the wealthy as tutors and witty companions. Some became noted scholars, and Condillac and his brother Mably, who was also an abbé, turned out to be among the most distinguished of them. D’Alembert, being unmarried and poor, seemed particularly to enjoy the company of these intellectual abbés, and he was associated with a number of them who were scholars at the Sorbonne. We know that d’Alembert was well acquainted with the abbé de Condillac during this time, and that he was greatly impressed with the abbé’s ideas. There are indications that Condillac himself was influenced by d’Alembert’s thoughts on scientific method. Condillac was early fascinated with the analytical method of Locke’s psychology, which struck him as the only truly scientific approach to the study of ideas, and he determined to carry it to its logical conclusions. It was in this branch of philosophy that he achieved his greatest eminence. The discussion of the implications of Newton’s methods for all philosophical endeavor also formed the object of an important part of his work. He was perhaps the best of the professional philosophers of eighteenth-century France. Condillac’s effect upon the thought of the Enlightenment was very great, and it was particularly noticeable in the Preliminary Discourse. However, possibly because he did not wish to be compromised by its unorthodoxy, he did not contribute actively to the Encyclopedia.

Spreading out beyond this rather bohemian circle of which d’Alembert was a part were the great world of Paris, the rest of France of the Old Régime, and all of Europe, in various states of progress and obscurantism. Scenes of wretchedness, filth, disease and death were daily and public experiences for them all, along with great extremes of luxury and privilege. D’Alembert and his companions lived in a society that was legally defined as one of unequals, in which there existed a host of accretions from the past that had outlasted their usefulness. The general prosperity of almost all classes in France had been rising over the last hundred years. There was a thriving community of professional and business people, who, along with the more intelligent aristocrats and clergy, were responsive to the exchange of ideas and information in literature and to the enjoyments of art. That prosperity made it possible for a man like Diderot to scrape together enough to exist on, albeit miserably, as a professional literary man, and it made it possible in the long run for his ideas and projects and those of men like him to have some real effect in the world which was beginning to be able to afford them.

This is no place to try to sketch the elaborate institutions and abuses of the western Europe of the Old Régime, the old philosophies and interpretations of man and society, and the prejudices and intolerance—or to balance them with a description of the real charms and virtues of that civilization. It must suffice to note that certain forces were at work in all western Europe that progressively brought about fundamental transformations in almost all the important features of that society in the next several generations. France was particularly stirred by the developing spirit of criticism. Through his own study and through his intellectual associations in the Academy of Sciences, the salons, and the circle of Diderot, d’Alembert became caught up in the wave of social and intellectual energy that had agitated the monarchy since the end of the seventeenth century and that was being formed into the philosophy of the Enlightenment by the philosophes. The Preliminary Discourse itself is one of the best contemporary intellectual records of the enthusiasms shared by d’Alembert and his fellow men of letters during those exciting years when the first volume of the Encyclopedia was in preparation. Much of the invigorating thought of the liberal centers of the north had found its way into France, partly through the journalistic activities and translations of the exiled Huguenot intelligentsia, partly through the work of Dutch scientists and critics, and partly through direct communication among various men throughout the international republic of letters. The “English philosophy” of Bacon, Newton, and Locke had become the rage among the philosophes. Indeed, d’Alembert was at the forefront of those who truly understood the scientific implications of Newton’s work and who transmitted the best of the Newtonian experimental method from England and Holland to France. In addition, he rapidly assimilated a host of stimulating philosophical and social ideas from England, which animated the conversations and writings of his colleagues toward the middle of the century and formed the basis of the Preliminary Discourse.

At the same time, d’Alembert and his friends could not have been insensitive to the importance of the intellectual community and tradition of France itself. The many debts of the encyclopedists to their predecessors, and especially to Descartes, are eloquently recognized in the Preliminary Discourse, which testified also to the inspiration they drew from the great patriarchs of the Enlightenment: Fontenelle, Montesquieu, and Voltaire. Fontenelle (1657–1757) was still alive in 1750. D’Alembert knew him as a colleague in the Academy of Sciences and sat at his feet in the salon of Madame Geoffrin. All the young philosophes were attentive students of the precedents established by Fontenelle for conveying philosophical, critical, and scientific information to the literate public in a brilliant style, and they learned from him how to apply the new methods of philosophy and the discoveries of science to the criticism of various aspects of the social and intellectual heritage of the Old Régime. Similarly, most of them were partisans and disciples of Montesquieu (1689–1755), who had emerged at this time as the great French critic and commentator on the social, political, legal, and constitutional nature of society, and who threw his ponderous influence upon the side of reform. In matters having to do with political theory Montesquieu became the supreme authority for the Encyclopedia. Above all, the young philosophes admired Voltaire (1694–1778), whose every work of literature, satire, and social criticism stimulated a wave of excitement among the bohemian literati of Paris, and who showed them how to be mordant and “philosophical” when they dealt with the shortcomings and prejudices of their society. The extraordinary eminence of Voltaire was the prime demonstration to the encyclopedists of the power that lay in the hands of men of letters.

Near the middle of the eighteenth century the long development of ideas and attitudes described above reached a critical point in its relationship to the circumstances of French society in general. Widespread disgruntlement was evident against the abuses of the sorry reign of Louis XV; there was a sharpened edge of dissatisfaction in the air. The change that came over certain features of French public opinion was later described in the following terms by a historian who had experienced it: “While we passed from the love of belles-lettres to the love of philosophy, the nation . . . passed over from acclamations to complaints, from songs of triumph to the clamor of perpetual remonstrances, . . . and from a respectful silence regarding religion to importunate and deplorable quarrels. . . . Then it was that there arose among us what we have come to call the empire of public opinion. Men of letters immediately had the ambition to be its organs, and almost its arbiters. A more serious purpose diffused itself in intellectual works: the desire to instruct manifested itself in them more than the desire to please. The dignity of men of letters, a novel but accurate expression, quickly became an approved expression and one in common use.”[10]

The point of view of the intellectuals themselves at mid-century is best expressed by d’Alembert in his Élémens de philosophie of 1759: “If one looks with an attentive eye upon the middle of our century and considers the events which perturb, or at least concern, us, our customs, our works, and even our conversations, it is difficult not to perceive that in several respects a most remarkable change has taken place in our ideas, a change which, by its rapidity, seems to promise us a greater one yet. . . . Our century has called itself . . . supremely the century of philosophy. . . . The invention and use of a new method of philosophizing, the kind of enthusiasm which accompanies discoveries, a certain elevation of ideas which the spectacle of the universe produces in us—all these causes must have excited a lively ferment of minds. With a sort of violence this ferment . . . has turned upon everything that was exposed to it like a river which has broken its dikes. . . . Thus, from the principles of the profane sciences to the foundations of revelation, from metaphysics to matters of taste, from music to ethics, from scholastic disputes of theologians to matters of commerce, from the rights of princes to those of peoples, from natural law to the arbitrary laws of nations—in a word, from the questions that touch us most to those which interest us only mildly, everything has been discussed, analyzed, or at least stirred about.”[11]

A remarkable cluster of critical works appeared at nearly the precise middle of the century: Montesquieu’s Esprit des Lois (1748), Buffon’s “Premier discours” to his Histoire naturelle (1749), Condillac’s Traité des systèmes (1749), Turgot’s Discours at the Sorbonne on the progress of the human mind (December, 1750), Rousseau’s Discours [sur les Sciences et les Arts] (1750), and Voltaire’s Siècle de Louis XIV (1751). At this conjuncture of landmarks came the first volume of the Encyclopedia in June of 1751 with its Preliminary Discourse by d’Alembert. Immediately the encyclopedists were recognized as the chief spokesmen of the philosophes. We turn now to a brief history of their enterprise.

At its beginnings the Encyclopedia was no more than a venture for profit, projected by a shrewd French publisher. It was to be a translation of the Cyclopaedia of Ephraim Chambers (1728), an extremely successful English reference work. Only after a hectic and amusing sequence of frauds, quarrels, and blunders were d’Alembert and then Diderot brought into the project, at first as subordinates and finally as editors. Once they were given full control of it, they proceeded to expand its scope vastly and to breathe new inspiration and energy into it. The work was to contain nothing less than the basic facts and the basic principles of all knowledge; it was to be a sort of war machine of the thought and opinion of the Enlightenment.[12]

Neither d’Alembert nor Diderot anticipated that their project would become the center around which the major contending intellectual and emotional factions of France would crystallize. The encyclopedists enjoyed being daring and even shocking, but they were hardly active revolutionaries; one might even say they were rather happy in the world they lived in. Nonetheless, the publication of the Encyclopedia became the cause célèbre in the intellectual world of the century, almost as the Dreyfus case was in the political world one hundred and fifty years later. Even before the publication of the first volume, an initial sign of trouble appeared in the influential Jesuit periodical, the Journal de Trévoux, a few weeks after Diderot’s Prospectus announced the work, and some time before d’Alembert’s Discourse. The Jesuit journal published certain criticisms of the claims that were made by Diderot for the projected Encyclopedia, and it implied that the encyclopedists had plagiarized from Bacon.[13] Diderot and d’Alembert responded angrily. The opening passages of the Preliminary Discourse are intended as a refutation of these criticisms.

But the Jesuits had good reason to suspect the orthodoxy of Diderot’s religious opinions from the evidence of a number of his works already published, and they had equally good reason to wonder about the attitude of the other contributors to the Encyclopedia in matters of religion. They had not themselves been asked to contribute the theological articles; yet they considered themselves the guardians of orthodox theology and defenders of the faith in all respects. They spoke for a very substantial segment of the society of the Old Régime that was growing increasingly concerned about the new “philosophy” and its implications for the doctrines and authority of the Church. Diderot was in an aggressive mood and so were a number of other men of letters, who for a variety of reasons were determined to make a stand for the freedom to express their ideas as they saw fit. The sharp exchange that resulted from the Prospectus was one of the first open confrontations between the philosophes and the Jesuits.[14] But the Jesuits were only a fraction of the orthodox, although the most alert. The quarrel with them was the opening shot of a long and bitter disputation which broadened out to include larger segments of French society.

The serious opposition to the publication of the Encyclopedia came in waves. Churchmen and pious laymen who were alarmed by the ideas that appeared in the first two volumes of the work began to exert pressure on the royal government to put into effect certain long-established measures of repression against dangers to religion, morality, and the authority of the state. At the same time the work was welcomed with widespread enthusiasm, and a host of men of letters and public-spirited amateurs volunteered their services to the enterprise. The scandal caused by the thesis submitted to the Faculty of Theology of the Sorbonne by one of the contributors to the Encyclopedia, the abbé de Prades, brought the first major crisis to the enterprise. The thesis, which included whole paragraphs taken directly from d’Alembert’s Preliminary Discourse, was first accepted and then condemned as heretical.[15] In the atmosphere of shock and repressiveness that resulted from the knowledge that the new philosophy had penetrated even to the citadel of orthodox theology, the first two volumes of the Encyclopedia were suppressed, largely because of the suspicious personal and intellectual association between the condemned abbé de Prades and the encyclopedists. Favorable public opinion and a sympathetic faction within the royal government allowed the project to continue once more, but in 1759, after a growing storm of opposition and polemic, the government officially condemned the Encyclopedia, and the work could be continued only clandestinely. Many of the contributors, either fearful or exasperated with the persecutions, abandoned the project. D’Alembert refused to have anything more to do with it, except for the strictly mathematical sections. Diderot, with a faithful core of collaborators, of whom the chevalier de Jaucourt (1704–1780) was the chief, secretly carried through work on the last ten volumes of text until their completion in 1765. What had seemed a victory for the enemies of the philosophes could not in fact be made decisive, while the strength of those elements of the society sympathetic to the encyclopedists became more and more an accepted fact. By 1765, in an inconclusive way to be sure, the republic of letters associated with the encyclopedists had accomplished a change in the atmosphere of the society of the Old Régime that represented a considerable victory for the new opinions and the power to express them over the objections of the forces of repression. By virtue of the lethargy of the conservatives and the quickening pace of change everywhere, the attitudes toward the world expressed by d’Alembert in the Preliminary Discourse were conquering an increasing proportion of the effective forces of society. Let us now turn directly to that document.

The Preliminary Discourse first appeared, along with Volume One of the Encyclopedia, on June 28, 1751. At the outset of his collaboration in the encyclopedic project d’Alembert apparently considered his task to be connected solely with editing the mathematical part of the work. With the exception of two eulogies to fellow academicians, he had not published anything beside scientific works. Why, one might ask, did he, and not Diderot, write the Preliminary Discourse? We cannot reply with confidence to that question, for no evidence has come to light yet about the immediate circumstances of d’Alembert’s composition of it. We know he was working on it in January, 1751, from a letter of Diderot to Father Berthier of the Journal de Trévoux.[16] However, d’Alembert apparently was not contemplating writing an introduction to the Encyclopedia at the time of Diderot’s imprisonment when the huge project was already rather far along in its preparation. In September of 1749 he wrote Formey, the secretary of the Berlin Academy: “The detention of M. Diderot has become much less severe; nevertheless it still lasts, and the Encyclopedia is suspended. I never intended to have a hand in it 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.”[17] Up to this point in his career d’Alembert had never considered himself a serious writer on subjects other than natural science. In a short autobiographical memoir written later in his life he stated that in his passion for mathematics he completely abandoned the culture of belles-lettres which he had formerly enjoyed. He did not return to them, according to his own account, until several years after his entry into the Academy of Sciences (in 1741) at the age of twenty-three, and around the time when he began to work on the Encyclopedia, which would be in 1745.[18] One would hardly have expected him to take over the very critical task of composing the definition, so to speak, of the Encyclopedia with such scant experience in writing. There may, however, have been strategic reasons. D’Alembert was far better known than Diderot. He was a distinguished member of the three great scientific societies of Europe: the French Academy of Sciences, Frederick the Great’s Academy of Berlin, and the English Royal Society. And further, he had no reputation for heterodox and dangerous philosophy, such as Diderot had acquired already in a number of his writings.

The fact that the Discourse was d’Alembert’s first serious venture outside of mathematics and natural science makes it a truly impressive accomplishment, although he had shown a penchant for “philosophical” writing in the introductions to his scientific treatises, parts of which he transplanted directly into the Preliminary Discourse. Later he described the work as “the quintessence of the mathematical, philosophical, and literary knowledge that the author had acquired over twenty years of studies.”[19] It seems most likely that Diderot had some hand in it—if not in its actual composition, at least in the discussions that must have gone on concerning it—and his Prospectus in a slightly modified form made up the last part of it. We can also be certain that d’Alembert had at his elbow copies of the works of Condillac published up to that time. Indeed, he may have had Condillac himself at his elbow. The work can be considered the product of the conversations and exchanges among these young men, and ultimately of the opinions and information they derived from a very lively atmosphere of criticism and scholarship stretching back to the seventeenth century.[20]

The Substance of the Work

After giving over a few lines to refuting certain charges made against the encyclopedic project, d’Alembert launches squarely into the substance of his work. It is divided into four sections: (1) The first part examines the genealogy and filiation of ideas and the genesis of the various sciences and arts that will form the basis of the Encyclopedia. D’Alembert calls this operation “the philosophic history of the mind.” (2) He follows it by a history of intellectual progress since the Renaissance. (3) After this comes a revised version of Diderot’s Prospectus of November, 1750, then (4) a list of the contributors to the first volume of the Encyclopedia. Following the Discourse was “A Detailed Explanation of the System of Human Knowledge,” which explains the chart or “tree” of knowledge used in the Encyclopedia, a short section called “Observations on the Division of Sciences of Chancellor Bacon,” an outline of the “General System of Human Knowledge according to Chancellor Bacon,” and a graphic chart of the encyclopedic organization of knowledge. Each of these serves as a supplement to the main work. D’Alembert states in his prefaces to the editions of 1753, 1759, and 1764 that Diderot’s Prospectus, his chart of human knowledge, and the explanation of that chart were a necessary part of the Discourse. No doubt Diderot was also responsible for the observations on Bacon and the outline of Bacon’s system of knowledge, since both are marked with an asterisk, Diderot’s sign of attribution in the Encyclopedia. By far the most important parts of the Discourse are the two initial sections to which we now turn, where d’Alembert presents the philosophical foundations of the Encyclopedia as he discusses the natural history of the mind and makes his eulogy to its progress since the Renaissance.

The Method of the “Discourse” and the “Encyclopedia”

The Encyclopedia was a response to the growing demand of the intellectual community of Europe since the seventeenth century for a new summa of all the branches of knowledge in the light of the major discoveries that had been made in the past one hundred years—a synthesis based upon secular and naturalistic principles rather than upon a traditional theological teleology. Diderot and d’Alembert claimed only to lay the foundations of the true encyclopedia of knowledge in their work, but they hoped at least to propagate the true method of analysis and discovery by which it could be achieved, and to make a contribution to the process of gathering together the essential facts and principles that had been established, or whose validity had been confirmed, by that method. D’Alembert thought he found in the spirit of rigorous analysis, similar to that which produced the recent triumphs of the natural sciences, the means to bind all the disciplines together into a mutually supporting unity that would not be so rigidly systematic as to impose dogmatic limits on the search for new facts. The method and system he envisaged was designed to organize all our valid information and at the same time to facilitate the discovery of more facts and principles that would be useful to humanity.

In the Discourse d’Alembert was not only attempting, then, to establish the principles of order upon which the Encyclopedia was to be built, he was expounding what might be called the “discourse on method” of the Enlightenment, which he was convinced would progressively give mankind the power of independently shaping and directing its own destiny. In that process he reviewed the history of the progress made thus far in establishing the new “method of reason” and warned of certain pitfalls and errors to be avoided. Out of his discussion we can distill a particular philosophy of history and a number of assumptions that were characteristic of the Enlightenment.

The method of the Preliminary Discourse represents an adjustment of the rationalist spirit of Descartes to the empiricism of Locke and Newton—a fusion of traditions which lies at the foundation of the Encyclopedia. We may define “rationalism” as an intellectual orientation (particularly notable in the metaphysical systems of the late seventeenth century) which assumes the existence of certain absolute principles or truths instinctively or clearly felt to be true, through which the chief truths of phenomena can be deduced, judged, or explained. “Empiricism” is an intellectual orientation associated with the names of Bacon and Locke, and based on the assumption that “hard facts” of experience, experimentation, and physical sensations are the essential elements from which our valid ideas are derived and which are the source of all true knowledge. Let us look at what d’Alembert borrowed and what he rejected from each of these traditions and their proponents who preceded him.

Although d’Alembert considered Descartes a great intellectual hero because he dared to found philosophy upon systematic doubt and independent human reasoning rather than authority, neither he nor his colleagues could accept a major distinction Descartes had made between the world of physical phenomena and the mind, whereby the one was alleged to be wholly suspectible to the rules of “scientific” study, while the other involved certain innate notions that defied analysis or demonstration. That distinction only fostered supernaturalism and dogmatism in areas they were striving to open for their critical study. The “innate ideas” of Descartes could be used to exempt certain religious, political, and moral domains from critical scrutiny, as priests and traditionalists had done for centuries by arguing that these ideas at the foundation of religion, politics, and morality were implanted by God or innately inscribed on the mind.

The philosophes whose opinions d’Alembert expressed did not wish to see any segment of study free of analysis and empirical confirmation. They postulated a division between mind and body, but what they wanted was nothing less than an “experimental physics of the soul," to quote one of the memorable phrases from the Discourse. It was John Locke who provided them with its foundations in his analytical sensationalist psychology, which asserted as its chief principle that nothing is in the mind that is not first in the senses. Everything that man knows can be analyzed into simple ideas occasioned by sensations. The great French student of Locke, the abbé de Condillac, presented to his compatriots a combination of certain features of Cartesian rationalism with the empiricism of Locke and Newton that was accepted as doctrine among the philosophes, and much of his thought was incorporated into the Preliminary Discourse. In d’Alembert’s exposition the clear and distinct sensation replaced the clear, distinct, a priori idea of Descartes as the basis of all truth or certain knowledge. With this foundation he thought the philosophes could build a complete and unified system of knowledge based upon hard facts and evidence. The laws of any discipline, he was convinced, could be discovered through the analysis of the sensations which produced our ideas, to the point where one that explained all the rest was found.

It should be said that the influence of Bacon upon the Discourse and the Encyclopedia was perhaps not as great as the pronouncements of the editors might lead one to believe. However enthusiastically d’Alembert may have praised Bacon as the mentor of modern intellectual times and as a proponent of experimentation, it is clear he did not literally accept the extreme inductive method of the English philosopher, which would practically have ruled out the physico-mathematical sciences. For Bacon’s intellectual utilitarianism, for his doctrine that knowledge is power, for his vision of mutual cooperation of all scholars in the progress of knowledge, and for his rejection of scholastic teleology, d’Alembert saluted him as a kindred spirit and a great pioneer. Bacon’s system of categorizing the various branches of knowledge was useful, with some revision, for the Encyclopedia, and Diderot and d’Alembert were much taken with many features of Baconian thought because they found it harmonized with their own. It does not seem, however, that many of the ideas of the Discourse were directly or originally occasioned by the English philosopher. In truth, the work was closer to Descartes. D’Alembert was concerned chiefly with the definition and connection of the principles of the various branches of human knowledge in the spirit of Descartes rather than the Baconian collection of information.

From the Cartesians come the empirically undemonstrable metaphysical assumptions of the simplicity and unity of phenomena that run throughout the Discourse and the Encyclopedia, representing a continuation of the great rationalist tradition of the seventeenth century into the heart of the so-called “empirical” Enlightenment. Much of the argument of the Discourse is built upon the assumption of the simplicity of principles or laws of the various disciplines. It is the same kind of simplicity that d’Alembert the geometer demanded in the essential propositions of his own science, and that, as a philosophe, he applied as an assumption to the whole range of knowledge. What can be known, he says in effect, can be reduced to simple terms, and this process of analysis into simplest terms can be extended to other branches of knowledge, if not by the application of mathematics or rigorous logic, at least by a process of arranging the facts within a field so that one finds the single fact that explains them all.

Not only are there simple laws behind each discipline, according to the encyclopedists, but there is also a unity that binds them all together. “The rationalistic postulate of unity dominated the minds of this age,” wrote Ernst Cassirer, “. . . The function of unification continues to be recognized as the basic role of reason.”[21] No one in the eighteenth century expressed that assumption of the unity of all phenomena and all knowledge better than d’Alembert, the geometer turned philosophe: “The universe, if we may be permitted to say so, would only be a single fact and a great truth for whoever knew how to embrace it from a single point of view” (see Part I). The Encyclopedia represents one step in the effort to achieve that single point of view.

Closely joined with this Cartesian “geometrical spirit” was the fruitful but ultimately undemonstrable idea that all things in nature constitute a continuous chain of being, and that the understanding of one fact is dependent upon an understanding of its relation to others in the continuity of beings in the universe. That notion, too, which Lovejoy traces to its maturity in the eighteenth century, appears throughout the Encyclopedia and receives a classic formulation in the Discourse. To discover the unknown links of the chain of being and at the same time make them useful for mankind became the program of knowledge of the philosophes.[22]

Although they assume at the outset that there are unity, simplicity, and continuity behind all phenomena, d’Alembert and his colleagues do not fall into the snares of the “spirit of systems” of the seventeenth-century rationalist philosophers whom they so much deplored. Repeating the argument of Condillac’s Traité des systèmes (1749), d’Alembert attacks the metaphysics of such great thinkers as Leibniz and Descartes, who based their philosophical systems upon certain “self-evident” or a priori principles. He tries to clear away a priori metaphysical speculations as undemonstrable and therefore conducive only to error and intellectual despotism. Moreover, he asserts that we know only individual things, that there are no “general beings,” and that our general notions are only abstractions of what we observe in individual objects (see these passages ). As we have seen, he put forth as the supreme method of achieving truth a combination of rationalism and empiricism closely paralleling the scientific method of the great Newton, which started with sense evidences, or “facts,” as the foundation for the discovery of all laws or principles, and which undertook to analyze each object or problem of the physico-mathematical sciences into its simplest elements and thereby to discover the essential principles behind it.[23] The assumptions of the unity, simplicity, and continuity of phenomena in no way prevent the unprejudiced study of the facts presented by the senses. Such are the essentials of the method d’Alembert suggests for the entire encyclopedic range of knowledge in the Discourse.

The Faculties of the Mind

D’Alembert divides his treatment of the human understanding according to the three faculties of the mind—Memory, Reason, and Imagination—which are operations of the mind defined according to what it does with the perceptions, sensations, or ideas it receives, reflects upon, or puts together. When making his “metaphysical” or logical discussion of the operations of the mind in an individual left in isolation, d’Alembert states that Memory is the first faculty to be exercised, since it involves only the recalling of sensations and ideas passively received by the mind. Reason comes next, involving the comparing, judging, and combining of sensations and the ideas they occasion; and Imagination comes last because it involves the construction of certain new ideas out of the perceptions stored by Memory and the combinations, comparisons, and judgments of Reason. By means of these faculties of the understanding, human beings, according to d’Alembert, historically developed a certain number of disciplines which he categorizes, for the sake of the arrangement of the Encyclopedia, beneath headings parallel to those three faculties. Under History fall all the disciplines which have chiefly to do with memory; under Philosophy those which have chiefly to do with reason; and under Imagination the various Fine Arts. Of course, he points out, the disciplines in the categories of both History and Fine Arts involve reasoning or Philosophy too, and thus are susceptible to the supreme “method of philosophy,” the empirical-analytical method which we have discussed earlier.

For all of the disciplines that make up the range of human understanding, d’Alembert asserts there are various means of judging the validity or excellence of the ideas, creations, or actions that constitute their substance. In the more purely intellectual disciplines such as mathematics, the natural sciences, and history, the standards of judgment are derived from the logical comparison of ideas and sense evidences according to the empirical-analytical method. That method is, of course, the prime means of invention, discovery of laws, and extension of the usefulness of all the disciplines involving the operation of reason upon sense evidence. But in those disciplines involving feeling or sentiment, such as ethics and aesthetics, the standards for judging validity and excellence involve both the analytical operations of the mind and something like an instinctive judgment of the sentiment which in ethics is conscience and in aesthetics, taste. It is in his discussions of these disciplines that we find the most ambiguity and uncertainty in d’Alembert’s exposition, and even something like a return to innate ideas. Moreover, in these areas he is most tempted to assert the existence of certain empirically or logically undemonstrable rights or laws. Nevertheless, he attempts to apply the operations of the method of reason and empiricism to a maximum extent in determining the origins and true principles of our moral and aesthetic sentiments themselves. But he is aware of the limitations of the “method of philosophy” in the study of the knowledge, intellectual creations, judgments, and behavior that are affected by our feelings or sentiments. Indeed, he specifically objects to excessive attempts to submit matters of sentiment and the heart to analysis.

The “Method of Philosophy” and Ethics

It is apparent in the Discourse that d’Alembert believes the rational analysis of human psychological, social, and historical experience might reveal the basic elements of a natural ethics. Through his sketchy remarks we see the outlines of a thoroughly materialistic ethical system which he was perhaps not willing to spell out in full detail. He derives our first and fundamental moral ideas above all from our reactions to the very material sensation of pain, and he baldly states that the sensible moralist should take the sovereign good in this life to be the exemption from pain. Further, he refuses to consider the question of morality and the origins of ethical ideas of man except as he is part of a society. The historical experiences that occasioned the first human ideas of injustice or right and wrong—that is, the first moral ideas—are derived by d’Alembert from the oppression of the weak by the strong in human society. In a brief but surprisingly Hobbesian passage he suggests the existence of a period in human history when men struggled in violent competition for the advantages that society had to offer, a period when brute force was supreme and fear was the dominant emotion. Although he did not explicitly say it in the Discourse, obviously he considered the law of self-preservation or of resistance to oppression to be the foundation of what he called the fundamental “natural law we find within us,” the source of all laws and government, and the principle of their necessity.

It was hardly a step from d’Alembert’s description of the historical foundation of ethics to a political and moral philosophy that took the general evaluation of pleasure and pain produced by any act as the sole practical and valid means of forming a moral judgment concerning it: and in fact during the course of the French Enlightenment, Helvétius, who was a friend of the encyclopedists although he himself did not contribute to the Encyclopedia, carried this line of thought in ethics and political theory to a highly heterodox set of conclusions. The final suppression of the encyclopedic project resulted in part from the association made by the orthodox between the position of the Encyclopedia and that of Helvétius, and, indeed, the first suppression of the work in conjunction with the de Prades scandal very much involved ideas to be found in the passages of the Preliminary Discourse we have been discussing, passages which were copied in large part directly into de Prades’ thesis.

D’Alembert’s assertions that the first ideas of right and wrong were derived historically from unhappy social experiences of man, without reference to the Christian tradition, of course brought an alarmed reaction among the orthodox, although he later pointed out that he was speaking only of the notion, not the essence, of good and evil. The essence presumably comes from God. He was attacked for restricting his discussion of ethics to man as a social being and not in his relation to God, as if there were no ethics without society or relationships of human beings. His description of man’s arrival at the idea of right and wrong historically before the idea of God only added to the indignation and suspicion. In short, he early encountered the difficulties, in an orthodox society, of viewing society and the history of our ideas and practices strictly from the standpoint of natural evidence, although he publicly denied that this approach rejected or refuted the divine plane of knowledge which he held to be largely beyond our reasoning and surely beyond the scope of the Encyclopedia.[24]

D’Alembert’s treatment of personal and political morality cannot always be reconciled with the “method of philosophy,” as for instance when he speaks of the right of equality, which cannot be proved through logic or demonstrated through any empirical means.[25] Moreover, we are left to wonder how he would have reconciled his doctrine of conscience as a feeling that judges the rightness or wrongness of an action with his sensationalist epistemology; the feelings of right and wrong imprinted on men’s hearts appear to be a new version of the proscribed innate ideas. Later he expressed indignation at those who criticized him, as he said, for agreeing with Pascal that there were truths that spoke to the heart as well as to the mind.[26] He does not make clear whether this moral conscience universally resulted from the earliest experiences of human beings in society and was taught almost automatically by one generation to the next, or whether it is an inherent part of human nature in the Rousseauian sense. In any case, he seemed to think its basic, valid judgments could be studied in the cumulative historical experience of mankind, that philosophes could turn to history and isolate the essentials of human moral nature, and thus the essentials of moral and political science, through the accumulation and comparison of a vast number of cases of human moral behavior.[27]

The Philosophy of History and the Idea of Progress in the “Discourse”

D’Alembert’s tendency to turn to history to establish the fundamentals of a science of ethics reflects a general tendency in the second part of the eighteenth century to look to history for enlightenment concerning the true nature of man and society. The Discourse encompasses two separate ways of approaching our ideas. The one approach finds their origins in the operations of the “isolated mind,” as distinct from history and inherited experience; the other studies the origins and progress of ideas and of truth in connection with the development and history of society. D’Alembert tries to fuse the two.

Descartes, Locke, and Condillac were chiefly concerned with a purely metaphysical description of the genealogy of ideas, independent of history. Although the Discourse derives much of its substance from these men, it also manifests a vital interest—hardly to be found in the speculations of any one of them—in the effect of historical experience on the development of ideas. Even when d’Alembert is writing what he calls the “metaphysical” account of the origin of knowledge in the first part of his essay, he derives the origins of certain ideas from the historical social experience of primitive man. Such is the case with the ideas of right and wrong and those which establish the earliest arts and sciences. And he sets his entire philosophical exposition of the bases of human knowledge in a loosely historical context. However, there are points in this early part of the Discourse where d’Alembert switches back and forth abruptly and confusingly from a metaphysical discussion of the genealogy of ideas in the “isolated mind” to a commentary on certain ideas that were produced as a result of historical development (pp. 11 ff.).

In the second part of the essay he moves squarely into the history of the progress of ideas, and in a sense the history of the progress of the method for achieving truth, since the Renaissance. There, to be sure, we are subjected to an untenable description of the origins of the Renaissance and a total rejection of the Middle Ages; and in addition we are affronted by the crude interpretation of history as no more than a series of moral lessons. But one observes also in the Discourse the elements of a philosophy of history which regarded truth as something that is developed gradually over the generations, and which therefore placed a premium on cultural history and the study of the relationship of ideas to society.

D’Alembert’s exposition of modern intellectual progress follows a sequence of stages that emphasize, one after the other, the three chief faculties of the human intelligence—Memory, Imagination, and Reason—which he discussed in his metaphysical description of the mind. Thus he seems to bridge the gap between his “timeless” metaphysics and his historical description of progress. The earlier stages of progress after the beginning of the Renaissance, according to d’Alembert, involved chiefly the revival and development of disciplines having to do first with Memory and then with Imagination. It is as if the exercise of these two faculties were the prerequisite for the revival of the third, Reason, in the historical process of civilization in modern times. The new method of truth or reason, in d’Alembert’s exposition, had been something developed through the progressive and cumulative exercise of human faculties over three centuries. He always favored the creative faculties of Imagination and Reason over that of Memory, and he found in modern history that the first, more “primitive,” stages of intellectual progress entailed the disciplines of Memory or erudition, whereas only later did the intellectuals and artists of Europe make notable progress in the creations of the faculties of Imagination and Reason. Thus, by his discussion of the evolving disciplines deriving from the various faculties of the human psychology, he provided a way to connect the nonhistorical or abstract metaphysics of the mind and the history of intellectual progress, the lack of which made it hard for Condillac, for instance, to square his psychology with his historiography.

As we have pointed out, d’Alembert’s “philosophical” interest in history is a symptom of the deeper and deeper preoccupation of the Enlightenment with the problems of society and the reform of society. Propagandists of the Enlightenment turned to history to find evidence, examples, and confirmations for their opinions, and to discover some meaning in the process for them. They were not interested exclusively in the isolated mind, separated from society and time. Bayle and Fontenelle had anticipated the turn toward history with their critical studies of historical evidence and their use of history as a means of refuting some prejudice or supporting some theory or opinion, and by mid-century their approach to history had taken root, amplified by an ever more critical attitude toward the contemporary institutions and customs of society. Montesquieu’s Esprit des lois (1748), that monumental study of the principles behind the vast and complicated facts of past and present political institutions, helped bring a fuller appreciation of the need to understand the forces of history. That work was soon followed by the publication of d’Alembert’s Preliminary Discourse, which occurred at practically the same moment as the delivery of Turgot’s Discourse on the progress of the human mind at the Sorbonne. Voltaire’s Age of Louis XIV followed soon afterward in 1751. All three are landmarks in the history of culture, the development of the idea of progress, and in the secular use of history as “philosophy teaching by example.”

D’Alembert undertook to combine Condillac’s empirical philosophy with an interpretation of intellectual progress throughout history, and to some extent so did Turgot. The remarkable parallels between their two works will strike anyone who reads them together. It is quite possible that these two men knew one another in 1750 and 1751, and we are led to wonder whether there was some direct relationship between their two historical studies. The authors of both shared similar judgments concerning the origins of ideas in the senses, the significance of Bacon and Descartes, the unity and interrelation of all truths, and the relationship of knowledge to society. Both delivered stirring eulogies to the progress of the mind, and both were filled with optimism that this progress would continue. Along with numerous other philosophes, both men were excited above all by the progress of the method of knowledge since the time of Bacon, a progress in which each genius was seen to add his contribution to the perfection of that method of critical analysis which gave an ever more perfect key to truth in all levels of life and society, and therefore the greatest hope for progress. Of the two, d’Alembert’s work is much the fuller treatment of the intellectual history of Europe since the Renaissance, but it must be said that Turgot expressed a far more sophisticated understanding of the continuity of historical development. He paid more attention to the ancient history of knowledge, and he was far from rejecting the entire Middle Ages and the period of the supremacy of the Church as being a loss to the intellectual progress of mankind. But he was in essential agreement with d’Alembert, and it is not surprising that he later became a contributor to the Encyclopedia.[28]

Condorcet, who at the end of the century made the supreme statement of the eighteenth-century idea of progress, recognized his old friends, d’Alembert and Turgot, as his intellectual masters. It might be added that he too was involved in the Encyclopedia, although he had been too young to contribute to the original volumes. But his collaboration in the four-volume Supplement to the work is one more indication of the extent to which the Encyclopedia became the organ and the fulcrum of all those who were apostles of progress and reform in the Old Régime. Condorcet also carried the reforming spirit represented and expressed by the work directly into the Revolution as one of its chief intellectuals before the Terror.

Thus did the Encyclopedia lie in the mainstream of modern Western civilization. Its editors did not conceive of it as a finished work, but only a step in the march toward truth through the mutual co-operation of men of letters in all the arts and sciences. It was something to build upon; its ideals needed perhaps centuries to be fulfilled before the true encyclopedia of knowledge could be put together. The editors felt as if they were standing at the brink of a new age, where man would have the power to control his own destinies and the material forces of the world. D’Alembert was conscious that the middle epoch of the eighteenth century would be memorable in the history of mankind. The true method of knowledge had been discovered, a method that built upon itself, a philosophy that had discovered the means to correct itself by critical analysis of ever more evidence. There was no end to the possibility of reducing all branches of human knowledge to the principles that united them and in so doing assuring new power, progress, and happiness to mankind. The Discourse was a challenge and a manifesto for the future.

The Spirit of Intellectual Liberty and Secularism in the “Discourse”

The Discourse was one of the many noble declarations of faith in intellectual freedom produced in the eighteenth century. “Liberty of action and thought alone is capable of producing great things,” d’Alembert wrote, “and liberty requires only enlightenment to preserve it from excess”. As we have seen, he demanded nothing less than the freedom of scholars to establish most of the intellectual disciplines upon a “natural” and secular foundation, untrammeled by the dictates of Religion and Authority. Clerical control in the intellectual domain was in his opinion the chief enemy. The example of England’s liberties, where both political and religious despotism were held in leash, was throughout the Encyclopedia his favorite illustration of how things ought to be. In the second part of the Discourse d’Alembert triumphantly recorded some of the early victories of the new ideas over that combination of Aristotelian authority and Christian dogma which purported to explain all phenomena definitively in terms of divine purposes and whose partisans were willing to use force, if necessary, to make good their claims. In d’Alembert’s words, Descartes was the heroic rebel who first “. . . dared . . . to show intelligent minds how to throw off the yoke of scholasticism, of opinion, of authority—in a word, of prejudices and barbarism. . . . He can be thought of as a leader of conspirators who, before anyone else, had the courage to arise against a despotic and arbitrary power and who, in preparing a resounding revolution, laid the foundations of a more just and happier government which he himself was not able to see established” (p. 80). Although d’Alembert raised a cry of victory over the defeat of the intellectual despotism of old, by implication he warned that there were still more battles to be won through the co-operation of men of intelligence against the forces of repression, and it is clear that he believed that victory might reform the condition of humanity.

Thus, everywhere throughout the Discourse we see d’Alembert firmly practicing his own doctrine of intellectual independence in the full range of encyclopedic enquiry. Theology, once queen of the sciences, is described by him as but an off-shoot of Philosophy, and he makes only a half-hearted gesture toward Revelation: “Some truths to be believed, a small number of precepts to be practiced: such are the essentials to which revealed Religion is reduced”. He deals with God merely as an abstraction reasoned naturally from the evidence of the senses, and he makes virtually no mention of salvation, the sacraments, the after-world, the Scriptures, or the importance of religious institutions and tradition. Man, not God, is the primary consideration, and the mind of man is the measure of all things. For the Augustinian interpretation of the history of humanity, which looks for a divine plan and origin of all institutions and all historical process, we have seen him substitute a thoroughly secular one. He finds the origin of society and of human intellectual disciplines in man’s material needs, ignoring any discussion of divine decrees, and he restricts his treatment to entirely secular and utilitarian sources of the ideas of inequality, law, and government. It was clear to all who read the work that although he was not openly opposed to the practice of religion, at least he was militantly anticlerical, and his anticlericalism led him, along with others of the Enlightenment, to seem to derogate the importance of the very dogmas upon which the priesthood based its power. This was the spirit that characterized the encyclopedic school as a whole.

The Equalitarian Implications of the “Discourse”

Certain ideas in the Discourse were not only corrosive to the practical and moral power of the Church in society—they were potentially corrosive to the system of hierarchy and of social and legal privilege that prevailed in the Old Régime. Neither d’Alembert nor his colleagues (with the exception of Rousseau) believed in anything like political democracy, and he had no intention of making his work a political pamphlet advocating changes in the constitution of his society. Yet it must be said that the Discourse foreshadowed to some degree the subsequent equalitarian evolution of Western civilization. D’Alembert speaks of the right of equality which was overthrown by force in past history. In effect he asserts that all men are equal in their sensations, which are the source of everything in the mind. He claims the only legitimate principle of distinctior among men is an intellectual one, and he waters down ever that assertion with the notion that all men can learn anything if they are taught properly, that is, if objects are presented to their sensations properly. The Encyclopedia as a whole was not written for the specialist, but was designed to help educate the general public. The editors welcomed their role as popularizers, propagandists, and educators, and this is perhaps a reason they were considered so dangerous by the Church.

One of the prominent features of the Discourse, as well as the Prospectus and the Encyclopedia, was the recognition their authors made of the importance of the tradesman and the artisan, for the encyclopedists were beginning to be in a position to see that technology might transform the conditions of the world more profoundly than anything dreamed of in earlier history. In this respect, d’Alembert seconds Diderot’s conviction that it must not be beneath the dignity of the philosopher to pay attention to such useful knowledge for humanity. That the trades and manual arts should have been prominently included in a monumental work of philosophic collection and synthesis of information by intellectuals at the head of the republic of letters was a dramatic gesture and a departure from tradition that had a notable impact upon the imagination of Europe. D’Alembert’s statements in the Discourse make a fitting philosophical introduction to the renowned descriptions of the arts and trades and the splendid technological plates of the Encyclopedia. But he does not try to draw explicitly democratic conclusions in political theory from his recognition of the practical importance and worth of the artisan.

If one examines the folio columns of the Encyclopedia he will find that in many respects it fulfills its definition in the Preliminary Discourse, and that in other respects it fails. Its dominant philosophy of history follows the lines laid down in d’Alembert’s introduction; its barrage of criticisms against scholasticism, the priesthood, and the imperfections of the society of the Old Régime are at certain points far sharper than anything in the Discourse. It represents a manful effort to gather together the basic principles and the basic facts of all the arts and sciences, and many of its articles are of exceptional quality.

The categories of knowledge defined in the Discourse were followed in the body of the work, but it must be admitted that the encyclopedic arrangement based on Bacon’s subdivisions had very little revolutionary effect upon the progress of knowledge. The editors presented it only as a provisional principle of organization, and it gave a certain unity and intellectual quality to the work. It served as a vehicle for advertising the virtues of co-operation among the disciplines and for the entire methodology of the Enlightenment. The system of cross references, about which so much was said, was not carried through consistently or perfectly. Nevertheless, they served as a constant reminder of the interrelationship of knowledge and an occasional device to make a covert jab at some notion or institution that the encyclopedists did not dare attack too openly.

There were many, including Diderot himself, who regretted that the splendid promise of the Preliminary Discourse was not carried through in the body of the Encyclopedia, which was indeed marred by a multitude of imperfections. Nevertheless, it was one of the great enterprises in the history of ideas of Western civilization, and it would have merited the gratitude of humanity if it had been no more than the occasion for the Discourse of d’Alembert.

D’Alembert and the “Discourse” after 1751

In the massive volumes of the Encyclopedia, and in the books he published independently of it, d’Alembert returned again and again to the Discourse and the themes he raised there, exhibiting his lifelong tendency to patch up, defend, and expand upon his earlier works. The ink was hardly dry on the Discourse when it first appeared in 1751 before he was thinking about reworking it, as he wrote in response to Hénault’s congratulations:

As for myself, I see many shortcomings in my work; I shall be happy if I can rectify them, as I intend, in the articles for which I am responsible in the Encyclopedia, where I propose to treat more thoroughly a large number of matters which the limits of the Preliminary Discourse allowed me to touch only lightly.[29]

At the time this was written d’Alembert was already formulating several major articles for the Encyclopedia in which he systematically elaborated on the themes of the Discourse. His articles on methodological and philosophical matters had a particular consistency and unity compared with the contribution of any other collaborator, and, so far as they went, they fulfilled the definition of purposes in the Discourse. Aside from the articles he wrote for the Encyclopedia as a philosophe and critic, the specialized articles he contributed on mathematics and the physical sciences were of uniformly high quality, as might be expected from the world-famous mathematician and physicist that he was.[30] Unfortunately, not all parts of the Encyclopedia were composed with equal skill.

For several years after 1751 d’Alembert continued to be excited by the renown that came to him from the Preliminary Discourse and the importance of his role as coeditor of such a monumental work as the Encyclopedia. At every turn he promoted and defended the latter with the fierce and combative energy that was characteristic of him throughout his intellectual life. He was thin-skinned, and his naturally contentious spirit was aroused to a white heat by the barrage of criticism leveled at the Encyclopedia by influential clerical and conservative enemies of the project. He inserted several polemical defenses of the work in the Encyclopedia itself and in separate publications; and his personal correspondence is marked by bitter complaints about the Encyclopedia’s enemies. Sometimes he went farther than Diderot thought wise. The harried chief editor was concerned to keep the project afloat, and he regarded his colleague’s intemperance to be foolhardy. In the delicate political circumstances of the time, for instance, d’Alembert’s defiant Preface to Volume Three of the Encyclopedia in 1753 was unnecessarily inflammatory in its denunciation of the powerful factions who had worked to have the project temporarily suppressed in 1752. Their influence was only growing stronger.

As the intensity of the attacks on the Encyclopedia, and particularly on his article on Geneva in Volume Seven, became more and more threatening, d’Alembert’s limited patience gave out altogether, and he withdrew as coeditor in 1758. He restricted himself thereafter to contributing to the mathematical part of the Encyclopedia, which was sufficiently uncontroversial, as he wrote, to be free of the clamorings of false zealots.[31]

Nevertheless, through all the turmoil d’Alembert continued to rework and touch up the Preliminary Discourse in multiple reprintings of it made in several editions of his ever-expanding Miscellany, or Mélanges.[32] When he finally put together his complete methodological philosophy in a major work, the Élémens de philosophie of 1759, he specifically defined it as the mature development of the themes he had first publicly addressed in the Preliminary Discourse.[33] The Élémens de philosophie, in turn, was expanded upon in 1767 in very substantial supplements that nearly doubled its length.

The Preliminary Discourse to the Encyclopedia continued to inspire d’Alembert to further philosophical and methodological reflections throughout his life, as it did numerous other thinkers of his era. But nothing he wrote later matched the lucidity and influence of the little masterpiece that has assured him a place among the luminaries of the eighteenth-century Enlightenment.


  1. The original French title of this work appears as “Discours préliminaire des editeurs” at the beginning of the first volume (1751) of the Encyclopédie, ou Dictionnaire raisonné des sciences, des arts et des métiers, par une société de gens de lettres. Mis en ordre et publié par M. Diderot, . . . et quant à la partie mathématique, par M. d’Alembert, . . . (Paris, Briasson, David l’aîné, Le Breton, Durand). The seventeen original folio volumes of text of that work were published from 1751 to 1765, the eleven volumes of plates from 1762 to 1772. Four supplementary volumes of text, one of plates, and two of index were published from 1776 to 1780, after Diderot’s editorship.
  2. Montesquieu, Oeuvres complètes, ed. A. Masson (Paris, 1955), III, 1480.
  3. Frederick the Great, Oeuvres (Berlin, 1854), XXV, 166. Letter of 1780 to d’Alembert.
  4. M. J. A. Condorcet, “Éloge de d’Alembert,” in Oeuvres complètes de d’Alembert (Paris, 1821), I, ix, read at the Académie des Sciences and published in 1784. Condorcet (1743–1794), a fellow mathematician and personal friend of d’Alembert, modeled his Esquisse d’un tableau historique des progrès de l’esprit humain in part after the Preliminary Discourse. The Esquisse, written in 1793 while Condorcet was in hiding from the Terror, was the most impassioned statement of faith in progress of the Enlightenment. Voltaire, although he apparently did not immediately recognize the merit of the Discourse, later excessively rated it superior to what he called the “method” of Descartes (Lettres sur Rabelais [1767], in Oeuvres, ed. L. Moland [Paris, 1879], XXVI, 513), and in this he was seconded by the nineteenth-century scholar, F. Picavet, who placed the Preliminary Discourse on an equal plane with the Discourse on Method (1637) in the introduction to the last French edition of d’Alembert’s Discourse (Paris, 1894), p. lviii. Among the anti-philosophes of the eighteenth century who nonetheless praised certain features of the work was even the bitterly hostile Jesuit Father Berthier, editor of the Journal de Trévoux, October, 1751, pp. 2270 ff., and October, 1759, p. 2565. The abbé Sabatier de Castres, who consistently attacked the encyclopedists in his Trois siècles de la littérature françoise (Paris, 1774), I, 40, regrets that the magnificent promise of the Discourse was not fulfilled in the Encyclopedia itself. In his Philosophie du dix-huitième siècle (Paris, 1818), I, 109–10, J. F. La Harpe, similarly an enemy of the philosophes, although he claimed to be a friend of d’Alembert, put him on a level with Pascal as a scientist and writer, because of the excellence of the Preliminary Discourse.
  5. Norman C. Torrey, “L’Encyclopédie de Diderot, une grande aventure dans le domaine de l’édition,” Revue d’histoire littéraire de la France, LI (1951), 317, states: “le ‘Discours préliminaire’ de d’Alembert reste le meilleur resumé de l’esprit du XVIIIe siècle.” Ernst Cassirer makes ample use of the Discourse and other works of d’Alembert in his Philosophy of the Enlightenment, tr. C. A. Koelln and J. P. Pettegrove (Princeton, 1951; Beacon paperback, 1955). The list of recent authorities who have made substantial references to the work would be a long one indeed.
  6. This was the publisher who in 1746 purchased Diderot’s Pensées philosophiques, a book which was immediately condemned to be torn up and burned by the public executioner as being contrary to religion and morals. Later Durand was an associate publisher of the Encyclopedia (see n. 1).
  7. Jean-Jacques Rousseau, Confessions, ed. Van Bever (Paris, 1926), II, 164–67. The Confessions was published posthumously.
  8. A. R. Oliver, The Encyclopedists as Critics of Music (New York, 1947), p. 157. The most ambitious study of d’Alembert’s thought is Maurice Muller’s Essai sur la philosophie de Jean d’Alembert (Paris, 1926). The standard biography, which leaves much to be desired, is Joseph Bertrand’s D’Alembert (Paris, 1889). John N. Pappas, in his Voltaire and d’Alembert (Bloomington, Indiana, 1962), examines d’Alembert’s career as a philosophe, for the most part after he ceased to be an active editor of the Encyclopedia; Marta Rezler has discussed an important source of information concerning the life of d’Alembert in The Voltaire-d’Alembert Correspondence: An Historical and Bibliographical Re-Appraisal, in Studies on Voltaire and the Eighteenth Century (Geneva, 1962), XX, 1–139. While this introduction was in press, the publication of Ronald Grimsley’s biography of d’Alembert was announced, a work that will no doubt answer the need for a thorough and scholarly study of d’Alembert’s life. The standard edition of the writings of d’Alembert is the Oeuvres complètes de d’Alembert (5 vols.; Paris, 1821–22), which is the one used for the introduction and notes to this work.
  9. A. M. Wilson’s Diderot: The Testing Years, 1713–1759 (New York, 1957) has the most complete account of the activities of Diderot and his friends at this period of his life. It has also the best treatment of the history of the Encyclopedia to 1759.
  10. Rulhière’s speech to the French Academy, 1787, is reported by A. M. Wilson, Diderot, pp. 94–95.
  11. Oeuvres, I, 122–23.
  12. The history of the Encyclopedia is well recorded by Joseph Le Gras in Diderot et l’Encyclopédie (Amiens, 1928); F. Venturi, Le Origini dell’ Enciclopedia (Rome, 1946); A. M. Wilson, Diderot; and J. Proust, Diderot et l’Encyclopédie (Paris, 1963).
  13. Journal de Trévoux, January, 1751, pp. 188–89. The Prospectus appeared in November of 1750, announcing the enlarged project of the Encyclopedia.
  14. John N. Pappas, Berthier’s Journal de Trévoux and the Philosophes (Geneva, 1957), pp. 171 ff.; and Wilson, Diderot, pp. 117 ff.
  15. The Apologie de Mr. l’abbé de Prades (Amsterdam, 1753) reproduces the thesis in both Latin and French. Franco Venturi, in Jeunesse de Diderot (Paris, 1939), pp. 195 ff., includes quotations from the thesis of de Prades that are word-for-word transcriptions of the Preliminary Discourse.
  16. Diderot, Correspondance, ed. G. Roth (Paris, 1955), I, 106.
  17. Quoted in Wilson, Diderot, p. 115.
  18. Oeuvres, I, 2–3; and Bertrand, d’Alembert, p. 34.
  19. Oeuvres, I, 3.
  20. Charles Palissot, an outspoken enemy of the encyclopedists, attempted to cast doubt upon d’Alembert’s authorship of the work. In his Mémoires pour servir à l’histoire de notre littérature (Paris, 1803), I, 10, he asserts that d’Alembert’s friend, the abbé Canaye, remade the entire work from an inadequate and chaotic manuscript of the author. Stories of this kind are common in literary history, and this one deserves no more credence than the rest.
  21. Ernst Cassirer, Philosophy of the Enlightenment, p. 23.
  22. Arthur O. Lovejoy, The Great Chain of Being (Cambridge, Massachusetts, 1948). D’Alembert’s article “Cosmology” in the Encyclopedia, vol. IV, presents a memorable statement of the doctrine of continuity, as does the article “Elements of the Sciences,” vol. V. Nowhere are d’Alembert’s prejudices as a geometer more explicitly clear than when he applies the notion of the continuity or chain of geometrical propositions to the whole of phenomena and thus to all knowledge, as he does in the Preliminary Discourse.
  23. In the physical sciences this process is aided and confirmed by experimentation. See d’Alembert’s “Experimental,” Encyclopédie, VI, 34 ff. [sic], a most sophisticated discussion of the experimental method and its history.
  24. The venerable Journal des Sçavans, October, 1751, carried a long extract from the work, at the end of which was a series of warnings against the implications of what d’Alembert had to say concerning religion. The author accuses d’Alembert of consciously slighting matters of faith, and points out (pp. 218–23) some of the consequences of the secular morality formulated in the Discourse. In the same month of October, 1751, Father Berthier’s Journal de Trévoux similarly criticized certain points in the Discourse, without failing, however, to praise it in other respects. D’Alembert gave over a part of the introduction to volume III of the Encyclopedia (1753), pp. viii ff., to a bitter refutation of them, and he did the same in the introductions to the 1753, 1759 and 1764 editions of the Discourse (Oeuvres, I, 14–15). “Be Christian,” he wrote indignantly, “but on the condition that you will be Christian enough to avoid lightly accusing your brothers of not being so.”
  25. The Benthamites, using the utilitarian standard of the greatest good for the greatest number, were able to dispense with the undemonstrable notions of “natural laws of human beings” and “natural rights,” and thus avoided a recurrent difficulty in the thinking of the philosophes. It is clear that the French Enlightenment provided the intellectual and psychological foundation of the Benthamite utilitarian school of social reform, as it did for most of the other major reform programs that subsequently transformed the globe.
  26. Oeuvres, I, 15.
  27. See “Elements of the Sciences,” Encyclopédie, V, 495–96.
  28. Turgot, Oeuvres, ed. G. Schelle (Paris, 1913), I, 214–35. D’Alembert may have known Turgot at the time he wrote the Preliminary Discourse. Turgot was one of the group of abbés at the Sorbonne at the time he delivered his discourse on history, and later both he and d’Alembert regularly attended the salons of Madame du Deffand and Madame Geoffrin.
  29. Alembert, Jean Le Rond d’, Oeuvres complètes de d’Alembert, 5 vols. (Paris, 1821–22), V, 13–14.
  30. Several years after the first appearance of this edition of the Preliminary Discourse we were at last able to produce an exhaustive accounting of every contribution, great or small, that d’Alembert made to the Encyclopedia, so that it is possible to judge in detail how far he was able to carry through his plan. See our seven-volume census and technical study of the text of the work: Inventory of Diderot’s Encyclopédie, in Studies on Voltaire and the Eighteenth Century, Geneva, vol. LXXX, 1971 (Inventory, vol. I); Oxfordshire, vol. LXXXIII, 1971 (Inventory, vol. II); vol. LXXXV, 1972 (Inventory, vol. III); vol. XCI, 1972 (Inventory, vol. IV); vol. XCII, 1972 (Inventory, vol. V); vol. XCIII, 1972 (Inventory, vol. VI), Oxford; vol. 223, 1984 (Inventory, vol. VII).

    The entire text of the Encyclopedia—and thus the Preliminary Discourse and all of d’Alembert’s articles—is being made available in machine-readable form by the University of Chicago as part of the monumental ARTFL project, a textual database, under the direction of Professor Robert J. Morrissey. [See] The computer program for this project is based on the “Schwab Numbers” of our Inventory of Diderot’s Encyclopédie, and it gives students interested in doing further study of the Preliminary Discourse immediate access to the original French text and the texts of all of d’Alembert’s articles.
  31. See Inventory of Diderot’s Encyclopédie, vol. I, 198.
  32. Alembert, Jean Le Rond d’, Mélanges de littérature, d’histoire, et de philosophie (Berlin [Paris] 1753, 2 vols.; Amsterdam 1759, 1760, 1763, 1764, 1766, 1767, 1770, 1773, 5 vols). All the revisions and textual variations in d’Alembert’s own later editions of the Preliminary Discourse are listed in our Inventory of Diderot’s Encyclopédie, vol. I, Appendix E, 189–92.
  33. Alembert, Jean Le Rond d’, Essai sur les Eléments de Philosophie [edition of 1759 with “Eclaircissements” of 1767], Introduction, Notes, and Index by Richard N. Schwab (Hildesheim: G. Olms, 1965), 18–19.

Citation (MLA): Schwab, Richard N. "Translator's Introduction." In Jean Le Rond d'Alembert, Preliminary Discourse to the Encyclopedia of Diderot, translated by Richard N. Schwab with the collaboration of Walter E. Rex. Chicago: University of Chicago Press, 1995. ix-lii. The Encyclopedia of Diderot & d'Alembert Collaborative Translation Project. Ann Arbor: Scholarly Publishing Office of the University of Michigan Library, 2009. Web. [fill in today's date in the form 18 Apr. 2009 and remove square brackets]. <>.

Citation (Chicago): Schwab, Richard N. "Translator's Introduction." The Encyclopedia of Diderot & d'Alembert Collaborative Translation Project. Ann Arbor: Scholarly Publishing Office of the University of Michigan Library, 2009. (accessed [fill in today's date in the form April 18, 2009 and remove square brackets]). Originally published in Jean Le Rond d'Alembert, Preliminary Discourse to the Encyclopedia of Diderot, trans. Richard N. Schwab with the collaboration of Walter E. Rex (Chicago: University of Chicago Press, 1995), ix-lii.

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