# Leibniz

Modern philosophyLeibniz was a German philosopher of the 17^{th} century (1646-1716). He was a universal mind: in mathematics, he invented differential calculus; in physics, he formulated the law of conservation of energy. He was born in Leipzig, defended his doctorate in law in Nuremberg and became a librarian at the court of Hanover. In philosophy, he is known for his work the Monadology and his demonstration of the existence and perfection of God, author of the best of all possible worlds, which Voltaire mocked.

## The works of Leibniz summarised on this site

**Monadology**

In the Monadology, Leibniz sets out his famous principle of sufficient reason and defines the monad as the element of which the whole universe is made

## Bibliography

Here are the essential books if you wish to gain a better understanding of this author's thought:

Jolley, Nicholas, (ed.), 1995. The Cambridge Companion to Leibniz. Cambridge University Press.

Mates, Benson, 1986. The Philosophy of Leibniz: Metaphysics and Language. Oxford University Press.

Smith, Justin E. H., 2011. Divine Machines. Leibniz and the Sciences of Life, Princeton University Press.

Connelly, Stephen, 2021. Leibniz: A Contribution to the Archaeology of Power, Edinburgh University Press

Borowski, Audrey, 2024. Leibniz in His World: The Making of a Savant. Princeton University Press.

## Recommended videos

Conferences, symposia, radio broadcasts... here are 10 videos that will help you better understand Leibniz's thought.

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## Biography: life of Leibniz

### Youth

Leibniz was born in 1646 in Leipzig, Germany, in Saxony, at the end of the Thirty Years' War that had torn Europe apart.

His father, a jurisconsult, died when he was just 6 years old. A precocious child with great intellectual curiosity, he taught himself Latin.

By the age of fifteen, he was well-versed in Greek and Latin literature, but was also interested in the authors of his time, such as Descartes.

After obtaining his baccalaureate in ancient philosophy, he left for Jena to study mathematics at the University in 1663. He then went to Nuremberg to study chemistry. Finally, he enrolled at the University of Law in Leipzig. In 1666, after graduating as **doctor of law** at the University of Altdorf, he turned down a teaching post.

He met Baron von Boyneburg, who was to become his protector, and this encounter was to prove decisive for the rest of his career. He became his assistant, his lawyer and also his friend.

In 1670, he was entrusted with a political post: adviser to the Chancellery of the Electorate of Mainz. While living in Mainz, he prepared a vast reform of the law. He began to write political and scientific works.

### The voyage to France and the beginning of discoveries

In 1672, he was commissioned by Louis XIV on a diplomatic mission to try to secure peace between France and Germany.

For 4 years, he resided in **Paris**, where he met some of the great scientists of the time: the mathematician and astronomer Huygens, the philosopher Malebranche, etc. He was at the centre of a vast network of exchanges between intellectuals from all over Europe. He had no fewer than 1,100 correspondents.

He worked on squaring the circle and developed the **infinitesimal calculus**. Newton claimed authorship of this discovery, which led to a quarrel that lasted until the end of his life.

Finally, it seems that Newton was the first to conceive the idea, but that Leibniz published it first; for all that, neither plagiarised the other, having carried out their research independently.

In 1673, he designed a calculating machine that perfected the one Pascal had developed. He travelled to London to present his prototype. He was elected to the Royal Society. He took advantage of his position there to study the works of Newton.

In Paris, he perfected his most fundamental mathematical discovery: the **differential and integral calculus**.

In 1676, he met Spinoza in The Hague, and became acquainted with the contents of The Ethics, although he later denied this, due to the sulphurous reputation surrounding Spinoza's name.

The same year, he finally returned to Germany where, following the death of his protector, he sought a new situation.

He would have liked to come to France, but Colbert refused him a pension. So he stayed in Germany and was appointed librarian to the Duke of Brunswick-Lünebourg. He thus worked in the service of the House of Hanover, in what is now Lower Saxony, a position he held for 40 years.

### Fruitful thought

With his situation now stabilised, Leibniz entered a phase of intense creative activity. These forty years were very fruitful, intellectually speaking. It was during this period that he wrote most of his philosophical works.

He also devoted his thoughts to mathematics, religion and physics. In 1684, he published an article on differentials.

The year 1686 proved to be very fruitful:

On the mathematical front, he published his article on integrals.

On the physical level, he developed his **dynamics**, based on the conservation of force (in modern terms: energy).

Finally, on the philosophical level, he published in French his Discourse on Metaphysics.

Leibniz was equally fluent in German (his mother tongue), Latin (the language of scholars) and French (the language spoken at court in Germany).

In 1691 he wrote his work on dynamics, in which he used the terms "energy" and "action" for the first time.

In 1699, he was admitted to the Académie des Sciences in Paris. He then set about founding a similar system in Germany: the Brandenburg Society of Sciences, later the Berlin Academy, was founded on his initiative.

A Compte Rendu de l'Académie des Sciences de Paris of 1703 contains an article by Leibniz in which he sets out the principles of **binary calculus** (using only 0 and 1). Nearly 250 years before the advent of computing, this was the very principle on which the operation of computers would be based. But Leibniz concludes that he fails to see the usefulness of this mode of calculation, other than an "essential" beauty: that of the links that unite numbers.

### Old age

In 1710, he had his Essays of Theodicy published, and four years later, The Monadology, written in French. However, this work was only published posthumously.

He conceived the project of an **encyclopaedia**, or "universal library", which would make it possible to popularise knowledge and bring it within everyone's reach, but this never came to fruition.

He was recognised as the greatest intellectual in Europe, and several European courts paid him a pension. He corresponded with kings and queens, such as the first queen of Prussia, Sophie-Charlotte of Hanover.

Yet he died in 1716 in Hanover in total solitude. No tribute was paid to him, with the exception of the Académie de Paris. He left no fewer than 200,000 manuscript pages.

## Main works

Discourse on Metaphysics

New Essays on Human Understanding

Essays of Theodicy on the Goodness of God, the Freedom of Man and the Origin of Evil

The Monadology