GOTTFRIED LEIBNIZ (1646-1716) was one of the most wide-encompassing figures in Western philosophy and thought. His philosophical works encompass the question of God and theodicy, necessary and contingent truth and harmony. He was a mathematical genius, and is generally given joint credit with Newton for inventing calculus. (His works are earlier than Newton's, but were not widely distributed. We have generally adopted his notation rather than Newton's, however. Although Leibniz's notation was far superior to Newton's, his applications were often shaky and sometimes incorrect; see his papers on osculating curves, 1686 & 1692.) He was, like Blaise Pascal, an early experimenter with computing machines and developed the binary numbering system.

He was a contemporary of many great mathematicans, philosophers, and thinkers; he met Huygens, Spinoza, and Malebranche, among others. Some have argued that he derived some of his philosophical views from Spinoza, and some of his mathematical ideas from Newton, but these views apparently have little basis in fact. Leibniz came to calculus, for the most part, independant of Newton, and it appears that Spinoza had no more than a minimal influence on his philosophies.

Leibniz believed that reality is composed of monads, which might be considered individual minds; monads may be divine (i.e. God, who created the other monads), angelic, human, or animal. Monads, although distinct and individual, are "harmonized" with each other so that perceptions of one monad correspond to the perceptions of another. As God is the Harmonizer of the monads, everything that occurs has a distinct reason in the divine will. Since God is benevolent, this reality may then be considered "the best of all possible worlds"; everything that occurs is as good as it can be, given everything that exists and has come about before now. This philosophy raises some questions of theodicy; what reason does God have for allowing evil? His work Théodicée (1710) addressed this question.

Gottfried Wilhelm Leibniz was born on 1 July 1646 in Leipzig, Germany. His schooling as a child was poor, but he taught himself Latin and Greek, and proceeded to study what books were available to him in his father's library. The scholarly community in Leipzig was jealous of the intelligent, industrious young man, and refused to grant him a doctorate. In 1667, he was offered a chair at Aldorf, but he refused it; instead, he entered the service of elector Johann Philipp von Schönburg as a diplomat. He busied himself in the College of Appeals in Mainz as a secretary, librarian and legal counselor. On a diplomatic errand, he travelled to Paris in 1672; here he would remain for four years. The elector of Mainz died in 1673, and Leibniz's salary was cut. To make a living, he established a law practice; hoping that he would be noticed and become a member of the Académie Royal des Sciences; meanwhile he met Christiaan Huygens, the famous physicist who postulated that light was a wave and who discovered a satellite of Saturn.

In 1676, things got brighter for Leibniz; he was appointed the librarian of Johann Friedrich, Duke of Brunswick-Lüneburg, in Hanover. This was a well-paid job, and gave him plently of free time to pursue his other interests; namely, mathematics. He worked on differential and integral calculus during these early years of his Hanover service; the first traces of a working calculus date from the late 1670's. He came up, with the help of Otto Mencke, with a journal, the Acta Eruditorum, and in it published much of his work. The journal enjoyed a wide circulation in continental Europe.

Johann Friedrich died in 1679, and was succeeded by his brother Ernst August. Six years later, Ernst named Leibniz their councillor for life. In a geneological project for the Duke, Leibniz travelled all over Europe. He came to Modena in 1690, where he arranged a marriage twixt Rinaldo d'Este and Princess Charlotte Felicitas of Brunswick-Lüneberg. This Heiratspolitik greatly contributed to Hanover's achieving electoral status in 1692.

After Ernst August's death, Leibniz was greatly supported by Sophia Charlotte, the Duke's daughter. It was in this time that he wrote most of his philosophical works. Nouveaux Essais sur L'entendement humaine was written in 1710, and Monadologia wasn't completed until 1714, two years before his death.

In 1700, he travelled to Berlin to oversee the foundation of what was to become the Berlin Academy. Over the next decade, he would return to Berlin many times for this project. Work on the geneological project assigned to him by Ernst August continued, even after Ernst's death, encouraged by his successor, Georg Ludwig. Leibniz became the imperial privy councillor in Vienna in 1713; Sophia Charlotte died the next year, and his salary was again cut off until he returned to Hanover. Once there, he found that Georg Ludwig had left Germany to become King George I of England. He requested that he be appointed King George's court historian, and was told that he must first complete the geneology of the house of Brunswick. Gottfried Leibniz complied, and died working on it in Hanover on 14 November 1716.