Gottfried Wilhelm Leibniz was two years old when the Thirty Years’ War ended; he grew up in one of the most barren and unhappy periods of German history. But he had every educational opportunity then available, for his father was professor of moral philosophy at the University of Leipzig. Gottfried was a Wunderkind, eager for knowledge and in love with books. The paternal library was opened to him with the invitation “Tolle, lege” (Take and read). He began Latin at eight, Greek at twelve; he devoured history; he became a “polymath”—learned in many fields. At fifteen he entered the university, where the stimulating Thomasius was one of his teachers. At twenty he applied for the doctor’s degree in law; Leipzig refused it because of his youth, but he received it soon afterward from Nuremberg’s university at Altdorf. His doctoral dissertation there made such an impression that he was at once offered a professorship. He declined, saying that he had “different things in view.” Very few of the major philosophers have held university chairs.
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.