by Will Durant
Economically secure, intellectually free, he now dipped into all the movements and philosophies that were agitating renascent Germany. He had studied the Scholastic systems at Leipzig; he kept their terminology and many of their ideas, like the ontological proof for the existence of God. He imbibed the full Cartesian tradition, but salted it with Gassendi’s objections and atomism. He passed on to Hobbes, praised him as subtilissimus, and flirted with materialism. 6 Living for a time (1666–67) in Nuremberg, he sampled the mysticism of the Rosicrucians (Fraternitas Rosae Crucis), that Brotherhood of the Rosy Cross which alchemists, physicians, and clergymen had founded about 1654; he became its secretary and delved into alchemy, very much as his future rival Newton was doing at Cambridge. He left no idea untouched or unborrowed. Before he was twenty-two he had written several treatises, small in scope but swelling with confidence.
One of these, Novus Methodus docendi discendique luris (A New Method of Teaching and Learning Law) attracted the attention of a diplomat then staying in Nuremberg, Johann von Boineburg, who advised the young author to dedicate it to the Archbishop Elector of Mainz, and arranged to have it presented in person. The plan worked, and in 1667 Leibniz entered the service of the Elector, first as assistant in revising the laws, then as councilor. He remained at Mainz five years. He became familiar with Catholic clergymen, theology, and ritual, and began to dream of reuniting the sundered Christian creeds. The Elector, however, was more interested in Louis XIV than in Luther, for the insatiable King was spreading his armies into the Low Countries and Lorraine, too close to Germany, and was obviously anxious to swallow the Rhine. How could he be stopped?
Leibniz had a plan for that—indeed, two plans, brilliant enough for a lad of twenty-four. The first was to unite the western German states in a Rheinbund for mutual defense (1670). The second was to deflect Louis from Germany by persuading him to seize Egypt from the Turks. Relations between France and Turkey were at that time strained; if Louis (anticipating Napoleon by 128 years) were to send an expedition to conquer Egypt, he would capture control of the commerce—including Dutch commerce—that went from Europe through Egypt to the East, he would keep the soil of France free of war, he would end the Ottoman threat to Christendom, he would be the honored savior, instead of the dreaded scourge, of Europe. Boineburg so wrote to Louis, enclosing an outline of the plan from Leinbniz’ pen.* Simon Arnaud de Pomponne, the French foreign minister, invited Leibniz (February, 1672) to come and offer the plan to the King. In March the twenty-six-year-old statesman set out for Paris.
The generals foiled him and themselves. By the time Leibniz reached Paris Louis had mended his quarrel with Turkey, and had decided to attack Holland; on April 6 he declared war. Pomponne informed Leibniz that crusades were out of fashion, and he refused to let him see the King. Still hoping, the philosopher drew up for the French government a memorial, of which he sent a summary—the Consilium Aegyptiacum—to Boineburg. If the proposal had been carried out to success, France, rather than England, might have captured India and the rule of the seas. Louis’ decision, said Admiral Mahan, “which killed Colbert and ruined the prosperity of France, was felt in its consequences from generation to generation.” 8
Boineburg died before the Consilium reached him, and Leibniz mourned the loss of an unselfish friend. Partly for this reason he did not return to Mainz; moreover, he had been caught in the intellectual currents of Paris, and found them more stimulating than those that surrounded even the liberal and enlightened Elector. Now he met Antoine Arnauld of Port-Royal, and Malebranche, and Christian Huygens, and Bossuet. Huygens drew him into higher mathematics, and Leibniz began those infinitesimal calculations that were to lead him to the calculus.
In January, 1673, on a mission from the Elector of Mainz to Charles II, he crossed the Channel to England. In London he made the acquaintance of Oldenburg and Boyle, and felt the zest of awakening science. Returning to Paris in March, he gave more and more of his time to mathematics. He contrived a computing machine that improved upon Pascal’s by performing multiplication and division as well as addition and subtraction. In April he was elected, in absence, a member of the Royal Society. By 1675 he had discovered the differential calculus, by 1676 the infinitesimal calculus, and he had formulated his successful notation. No one any longer charges Leibniz with having plagiarized his calculus from Newton’s. 9 Newton had apparently made his discovery in 1666, but he did not publish it till 1692; Leibniz published his differential calculus in 1684, his integral calculus in 1686. 10 There remains no doubt that Newton was first in the discovery, that Leibniz reached his own discovery independently, that he antedated Newton in publishing the discovery, and that Leibniz’ system of notation proved superior to Newton’s. 11
The Archbishop of Mainz died in March, 1673, leaving Leibniz without official employment. Soon he signed an agreement to serve Duke John Frederick of Brunswick-Lüneburg as curator of the ducal library at Hanover. Still fascinated by Paris, Leibniz remained there till 1676, then traveled leisurely to Hanover via London, Amsterdam, and The Hague. At Amsterdam he talked with Spinoza’s disciples, and at The Hague with the philosopher himself. Spinoza hesitated to confide in him, for Leibniz was proposing to reconcile Catholicism and Protestantism, which might then join in suppressing freedom of thought. 12 Leibniz overcame these suspicions, and Spinoza allowed him to read—even to copy passages from—the manuscript Ethica. 13 The two men had several long conversations. Leibniz had much trouble, after Spinoza’s death, in concealing how deeply he had been influenced by the saintly Jew.
He reached Hanover toward the end of 1676, and remained in the employ of successive Brunswick princes through the remaining forty years of his life. He had hoped to be accepted as a councilor of state, but the dukes assigned him to care for their libraries and write the history of their house. He performed these tasks intermittently well. His voluminous history (Annales Brunsvicenses) was weighted and illuminated with original documents assiduously obtained; his genealogical researches in Italy established the common origin of the Este and Brunswick dynasties; and though the subject of his book was uncomfortably confining for so ambitious a genius, he lived to see the Brunswick family inherit England. He tried hard to be a German patriot; he pleaded with the Germans to use their vernacular in law; but he wrote his treatises in Latin or French, and was a shining exemplar of the “good European” and the cosmopolitan mind. He warned the German princes that their divisive jealousies, and their deliberate weakening of the Imperial power, condemned Germany to be the victim of better centralized states, and the battleground of repeated wars between France, England, and Spain. 14
His secret hope was to serve the Emperor and the Empire rather than the princes of the separate states. He had a hundred plans for political, economic, religious, and educational reform, and he agreed with Voltaire that it was easier to reform a state by converting its ruler than by slowly educating the masses, who are too harassed with board and bed to have much time for thought. 15 In 1680, when the Imperial librarian died, Leibniz offered himself for the post, but he added that he would not want it unless it carried with it membership in the Emperor’s Privy Council. His application was rejected. Returning to Hanover, he found some solace in the friendship of the Electress Sophia, and, later, of her daughter Sophia Charlotte, who gave him entree to the Prussian court, helped him to found the Berlin Academy (1700), and inspired him to write his Théodicée. For the rest he ennobled his modest position by corresponding with the leading thinkers of Europe, by making major contributions to philosophy, and by advancing a brave plan for the religious reunification of Christendom.
III. LEIBNIZ AND CHRISTIANITY
Was he himself a Christian? Outwardly yes, of course; a man with his zeal to pass from philosophy to statesmanship had to robe himself in the theology of his time and place. “I have endeavoured in all things,” said his preface to the Theodicy “to consider the need for edification.” 16 The writings that he published during his life were exemplary in th
eir faith; they defended the Trinity, miracles, divine grace, free will, immortality; and they attacked the freethinkers of the age as undermining the moral bases of social order. However, “he went to church little . . . and for many years did not communicate”; 17 the simple people of Hanover nicknamed him Lövenix (i.e., glaubt nichts—believes nothing). 18 Some students have credited him with two opposed philosophies: one for public consumption and the comforting of princesses; the other “a clear-cut affirmation of all the principles of Spinozism.” 19 “Leibniz fell into Spinozism whenever he allowed himself to be logical; in his published works, accordingly, he took care to be illogical.” 20
His efforts to reconcile Catholicism and Protestantism subjected him to the charge of indifferentism. 21 His passion for unity and compromise dominated his theology; while avoiding preachers, he labored to bring them together. Because he saw deeply he minimized surface diversities; if Christianity was a form of government, its creedal varieties seemed to him not instruments of piety and good will but obstacles to order and peace.
In 1677 the Emperor Leopold I sent Christopher Rojas de Spinola, titular bishop of Tina in Croatia, to the court of Hanover to suggest to the Duke, John Frederick, himself a convert to Catholicism, that he join in a campaign to reunite Protestants with Rome. Probably the plan had political fringes: the Elector at the time desired the support of the Emperor, and Leopold hoped for a stronger German unity and spirit against the Turks. For a while Spinola commuted between Vienna and Hanover, and the affair progressed. When Bossuet (1682) formulated the Gallican Declarations by which the French clergy defied the Pope, Leibniz may have been led to hope that France would join with Germany in a Catholicism sufficiently independent of the papacy to soften Protestant hostility to the ancient creed. In 1683, as the Turks were marching to the siege of Vienna, Spinola assembled at Hanover a conference of Protestant and Catholic theologians, and submitted to them “rules for the ecclesiastical union of all Christians.”
It was probably for this meeting 22 that Leibniz anonymously composed the strangest of the many documents that were found among his papers after his death. It was called Systema Theologicum, and purported to be such a statement of Catholic doctrine as any Protestant of good will might accept. In 1819 a Catholic editor published it as evidence that Leibniz had been secretly converted; more likely it was a diplomatic effort to reduce the theological gap between the two communions, but the editor was justified in considering the paper overwhelmingly Catholic. It began with brief impartiality:
After invoking the divine aid by long and earnest prayer, putting aside, so far as is humanly possible, all party spirit, looking at the religious controversies as though I had come from another planet, a humble learner, unacquainted with any of the various communions, bound by no obligations, I have, after due consideration, arrived at the conclusions hereinafter set forth. I have deemed it incumbent upon me to embrace them because Holy Writ, immemorial religious tradition, the dictates of reason, and the sure testimony of the facts, seem to me to concur in establishing them in the mind of any unprejudiced human being. 23
Thereupon followed a profession of faith in God, Creation, original sin, purgatory, transubstantiation, monastic vows, invocation of saints, use of incense, religious images, ecclesiastical vestments, and the subordination of the state to the Church. 24 This generosity to Catholicism might cast doubt on the document, but its authenticity as a work of Leibniz is generally accepted today. 25 Perhaps he hoped, by so supporting the Catholic view, to prepare for himself a commodious berth at the court of the Catholic Emperor in Vienna. And, like any good skeptic, Leibniz admired the sight, sound, and smell of Catholic ritual.
Thus the strains of music, the sweet concord of voices, the poetry of the hymns, the beauty of the liturgy, the blaze of lights, the fragrant perfumes, the rich vestments, the sacred vessels adorned with precious stones, the costly offerings, the statues and the pictures that awaken holy thoughts, the glorious creations of artistic genius, . . . the stately splendor of public processions, the rich draperies adorning the streets, the music of bells, in a word all the gifts and marks of honor which the pious instincts of the people prompt them to pour forth with lavish hand, do not, I trow, excite in God’s mind the disdain which the stark simplicity of some of our contemporaries would have us believe they do. That, at all events, is what reason and experience alike confirm. 26
All these arguments failed to move the Protestants. Louis XIV disrupted the décor by revoking the Edict of Nantes and making brutal war upon French Protestants. Leibniz set aside his agape for more gracious times.
In 1687, to consult scattered archives for his Annals of the House of Brunswick, he set out on three years of travel through Germany, Austria, and Italy. In Rome, on the assumption that he would accept conversion, the authorities offered him the curatorship of the Vatican Library; he declined. He made a brave attempt to obtain cancellation of the ecclesiastical decrees against Copernicus and Galileo. 27 After his return to Hanover he began (1691) three years of correspondence with Bossuet in the hope of reviving the movement for the reunion of Christendom. Could not the Roman Church call a really ecumenical council, one including Protestant as well as Catholic leaders, to reconsider and revoke the Council of Trent’s harsh branding of Protestants as heretics? The bishop, who had just bombarded these “heretics” with his Variations des églises protestantes (1688), replied uncompromisingly: if the Protestants wished to re-enter the sacred fold, let them accept conversion and end the debate. Leibniz begged him to reconsider. Bossuet held out hope: “I enter into the scheme. . . . You shall shortly hear what I think.” 28 In 1691 Leibniz wrote to Mme. Brinon with his usual optimism:
The Emperor is favorably disposed; Pope Innocent XI and a number of cardinals, generals of monastic orders, . . . and many grave theologians, having carefully considered the matter, have expressed themselves in the most encouraging terms. . . . It is no exaggeration to say that if the King of France and the prelates . . . who have his ear in this matter were to take concerted action the thing would not be merely feasible, it would be as good as done. 29
When Bossuet’s answer came it was crushing: the decisions of the Council of Trent were irrevocable; they had rightly held the Protestants to be heretics; the Church is infallible; no conference between Catholic and Protestant leaders could reach any constructive result unless the Protestants would agree in advance to adopt the decisions of the Church on the matters at issue. 30 Leibniz replied that the Church had often changed her views and teaching, had contradicted herself, and had condemned and excommunicated persons without just cause. He declared that he “washed his hands of all responsibility for whatever further ills the existing schism may have in store for the Christian Church.” 31 He turned to the apparently more hopeful task of reconciling the Lutheran and Calvinist branches of Protestantism, but here he met with an intransigence as hard and proud as Bossuet’s. At last he privately called down a plague upon all the rival theologies, and proclaimed that there were only two kinds of books with any value: those reporting scientific demonstrations or experiments, and those containing history, politics, or geography. 32 Outwardly, and laxly, he remained a Lutheran to the end of his life.
IV. LOCKE REVIEWED
Half of Leibniz’ product was an argumentum ad hominem, undertaken more or less incidentally as a discussion of some other writer’s ideas. His greatest book, which grew to 590 pages, began in 1696 as a seven-page review of Locke’s Essay concerning Human Understanding (1690), known then to Leibniz only from an abstract in Le Clerc’s Bibliothèque universelle. When the Essay appeared in a French translation (1700), Leibniz reviewed it again for a German magazine. He was quick to recognize the importance of Locke’s analysis, and generously praised its style. In 1703 he set himself to comment on it chapter by chapter; it is these comments that constitute Leibniz’ Nouveaux Essais sur l’entendement humain (New Essays on Human Understanding). When he learned of Locke’s death (1704), he left the commentary unfinished
. It was not published till 1765, too late to interfere with the pervasive influence of Locke upon Voltaire and other luminaries of the French Enlightenment, but in time to share in molding Kant’s epochal Critique of Pure Reason. It is among the most important productions in the history of psychology.
In form it is a dialogue between Philalethes (Lover of Truth), representing Locke, and Theophilus (Lover of God), representing Leibniz. The dialogue is vigorously sustained, and still makes good reading for any person of keen mind and endless leisure. The preface shows Leibniz in his most courteous mood, professing modestly to win readers by attaching his discourse to “the Essay on the Understanding by a distinguished Englishman, one of the most beautiful and esteemed works of this period.” The question to be discussed is stated with laudable clarity: “To know whether the soul in itself is entirely empty as the tablets upon which as yet nothing has been written (tabula rasa), according to Aristotle and the author of the Essay, and whether all that is traced thereon comes solely from the senses and experience; or whether the soul contains originally the principles of many ideas and doctrines which external objects merely call up on occasion, as I believe with Plato.” 33* The mind, in Leibniz’ view, is not a passive receptacle of experience; it is a complex organ that by its structure and functions transforms the data of sensation, just as the digestive tract is no empty sack but a system of organs for the digestion of food and its transformation into the needs and organs of the body. In a famous epigram Leibniz summarized and amended Locke: Nihil est in intellectu quod non fuerit in sensu, nisi ipse intellectus—“Nothing is in the mind that has not been in the senses, except the mind itself.” 36 Locke, as Leibniz noted, had recognized that ideas could come from introspective “reflection” as well as from external sensation, but had ascribed to a sensory origin all elements entering into reflection. Leibniz, on the contrary, argued that the mind of itself supplies certain principles or categories of thought, such as “being, substance, unity, identity, cause, perception, reason, and many other notions which the senses cannot give”; 37 and that these tools of understanding, these organs of mental digestion, are “innate,” not in the sense that we are conscious of them at birth, or always conscious of them when we use them, but in the sense that they are part of the native structure or “natural aptitudes” of the mind. Locke felt that these supposedly inborn principles were gradually developed by the interplay, in thought, of ideas originally sensory. But without such principles, Leibniz urged, there would be no ideas, only a disorderly succession of sensations; just as, without the action and digestive juices of the stomach, food would not feed us, and would not be food. In this measure, he boldly added, all ideas are innate—i.e., the result of the transforming action of the mind upon sensations. But he admitted that the innate principles are at birth confused and indistinct, and become clear only through experience and use.
