# Gottfried Wilhelm Leibniz

Gottfried Wilhelm Leibniz,
portrait of Christoph Bernhard Francke , around 1700; Duke Anton Ulrich Museum , Braunschweig
Leibniz Memorial , implemented in 2009 on the occasion of 600 years of the Alma mater lipsiensis in the new campus of Leipzig University

Gottfried Wilhelm Leibniz (born June 21, jul. / In Leipzig , † 14. November 1716 in Hannover ) was a German philosopher , mathematician , lawyer , historian and political advisor of the early Enlightenment . He is considered the universal spirit of his time and was one of the most important philosophers of the late 17th and early 18th centuries as well as one of the most important thought leaders of the Enlightenment . In the 18th century he was often referred to as "Gottfried Wilhelm Freiherr von Leibniz"; however, so far there has been no certification of an ennoblement .

In early writings by other authors, his surname - analogous to that of his father, Friedrich Leibnütz , and his paternal ancestors - was also written "Leibnütz", sometimes also "Leibnitz" ( French Godefroi Guillaume Leibnitz ) (his name is Latinized, for example. , there are several versions, Godefridus Guilelmus Leibnitius ). From 1671 he chose the spelling "Leibniz" for his family name.

## Life

Leipzig: Old Nikolaischule , which Leibniz attended for 6 years
Leibnizhaus in Hanover, new building with a faithfully reproduced facade (left building)
Copy of the Leibniz bust in the Leibniz Temple in Hanover

Leibniz was born in Leipzig on June 21, 1646 according to the Julian calendar, which was then valid in the Protestant territories of the Holy Roman Empire , and was baptized on June 23 in Leipzig's Nikolaikirche . His father was the lawyer, notary and professor for moral philosophy ( ethics ) Friedrich Leibnütz (1597–1652) from Altenberg in the Erzgebirge , his mother Catharina the daughter of the Leipzig professor and legal scholar Wilhelm Schmuck . In his second marriage the father had been married to the daughter of a bookseller. In the estate of the father and his two fathers-in-law there was accordingly an extensive and diverse library, to which the early death of the father gave the young Leibniz largely unattended access: "Not only the presence of the books, but also the absence of their owner" laid the Foundation stone for Leibniz's education. Eight years old when he learned in this library self-taught Latin and Greek language; At the age of twelve he developed the beginnings of a mathematical sign language while thinking through logical questions.

Leibniz attended the Nikolaischule in Leipzig from 1655 to 1661 , the original of which has been preserved and renovated. In 1661 he enrolled at the University of Leipzig and pursued philosophical studies with the theologian Johann Adam Schertzer and the philosophy theorist Jakob Thomasius . In 1663 he moved to the University of Jena in order to open up Pythagorean ideas under the guidance of the mathematician, physicist and astronomer Erhard Weigel .

In 1666, at the age of 19, Leibniz published his first book De Arte Combinatoria (On the Art of Combinatorics). With the first part of this book Disputatio arithmetica de complexionibus he received his doctorate in philosophy from Jakob Thomasius and Erhard Weigel in March of that year . Later that year, at the age of 20, Leibniz wanted to do a doctorate in law, but the Leipzig professors rejected him as too young. So he went to Nuremberg to catch up on what had been denied at the University of Altdorf . He was temporarily in contact with a local alchemical secret society, but soon ridiculed their experiments. According to Leibniz's own account, the Altdorf University offered him a professorship after his doctorate, which Leibniz refused.

Instead he entered the service of Archbishop of Mainz Johann Philipp von Schönborn until 1672 . During his time in Mainz, he lived in the Boyneburger Hof, the residence of the Electorate of Mainz, Oberhofmarschall Johann Christian von Boyneburg , who had given him a job as an employee of Hofrat Hermann Andreas Lasser. With Lasser he worked on a reform of Roman law ( Corpus juris reconcinnatum ) on behalf of the elector . His work Nova methodus discendae docendaeque jurisprudentiae (“A new method to learn and teach jurisprudence”) received a strong reception in relevant circles. In 1670, Leibniz rose to council at the electoral higher revision court despite his Lutheran denomination. In 1671 two treatises on physics were published. Drafts and fragments on metaphysics - which, in the sense of traditional natural theology, should philosophically substantiate basic theses of the Christian faith - and on politics show the wide range of the intellectual project in which these writings were located.

In 1672 Leibniz traveled to Paris at his own request, where he worked as court master for Boyneburg's young son. There he wanted to present the “Sun King” Louis XIV with a plan for a campaign of conquest against Egypt in order to dissuade him from the planned wars of conquest in Europe. But Leibniz did not dare to hand over the plan; over a hundred years later, however, Napoleon Bonaparte implemented it in the Egyptian expedition . In 1672/73 Leibniz completed work on his calculating machine with a graduated roller for the four basic arithmetic operations , presented them to the Royal Society in London and became a foreign member of this famous learned society. From 1675 he was also a member of the Académie des Sciences in Paris. The dual number system further developed by Leibniz laid the foundation for computer-aided information technology of the 20th century.

Electress Sophie von Hannover symbolically honors Leibniz with the laurel wreath , relief by Karl Gundelach , part of the historical frieze on the New Town Hall of Hanover

Years earlier, from 1668, the Guelph Duke Johann Friedrich had tried to appoint Leibniz as librarian to his residence city of Hanover . But only after several refusals did Leibniz, meanwhile in financial difficulties, finally accept the Duke in 1676. On the - very long - return trip from Paris he visited his friend Henry Oldenburg in London and his favorite philosophical enemy Spinoza in The Hague .

In Hanover, Leibniz was also appointed Hofrat around two years later. There he was in a lively exchange of ideas with Electress Sophie von der Pfalz . In addition to his work as a librarian, he had a variety of tasks: from 1682 to 1686 Leibniz dealt with technical problems in the mines in the Upper Harz Mountains. He stayed frequently in Clausthal , tried out new mechanical devices there and made numerous suggestions for improving the Upper Harz mining industry . From 1685 onwards, Leibniz traveled through Europe on behalf of the Welfenhaus to write a history of the Welfen - a project that he could not complete until the end of his life. Leibniz was involved in the political successes of the Hanoverian Guelphs, such as the electoral status in 1692 and winning the British royal crown in 1714, through legal opinions.

In 1698 Leibniz moved into a Leibnizhaus in Hanover, which is now named after him . Leibniz let his student and secretary, the later scholar Rafael Levi , also live here for years . The Leibnizhaus was destroyed in the Second World War and in 1983 it was rebuilt elsewhere with a reconstructed facade.

Leibniz was in close contact with other princes and tried to get a paid position. Under Ernst August Leibniz also became librarian of the Herzog August Library in Wolfenbüttel in 1691 . Emperor Leopold I presented Leibniz his plans for a coin reform, for money, trade and manufacturing, for financing the Turkish wars, for building an imperial archive and many other things. But he received only benevolent attention. In 1713 the Emperor awarded him the title of Reichshofrat with a small pension; his efforts for the post of Chancellor of Transylvania failed. Leibniz had to turn down the librarian position offered to him in the Vatican as well as that of a chancellor in the Hildesheim Monastery : These positions would have required his conversion to Catholicism. When Leibniz's employer, Duke Georg Ludwig, became King of Great Britain, he refused Leibniz's wish to accompany him to his new court in London: Leibniz stayed in Hanover until the end of his life.

His connections to the Brandenburg-Prussian court, where Leibniz was often a guest, were more successful: Leibniz maintained a close intellectual exchange with Queen Sophie Charlotte , sister of his Hanoverian employer. With the support of Sophie Charlotte, a Royal Prussian Academy of Sciences was founded in Berlin in 1700 (today the Berlin-Brandenburg Academy of Sciences ) based on the English and French models; Leibniz became its first president. In order to extend this success, he conducted negotiations in Dresden in 1704 and in Vienna in 1713 on the establishment of a Saxon and imperial academy; He also proposed the establishment of a Russian Academy of Sciences to Tsar Peter the Great , which he put into operation in 1724. The academy concept embodied Leibniz's ideal of science, combining theoria cum praxi, theory and practice in systematic cooperation , and is thus at the center of his intellectual project.

Gottfried Wilhelm Leibniz was allegedly at the end of 1711 by Emperor Karl VI. ennobled and raised to the rank of baron; however, the corresponding certificate is missing.

Memorial stone in the Neustädter Church in Hanover

Shortly before his death, relations with the House of Hanover cooled down, which was now under the direction of Georg I. Ludwig . Leibniz died alone on November 14, 1716 at the age of 70 in Hanover and was buried there in the Neustädter Hof- und Stadtkirche St. Johannis . The context of the funeral ceremony is controversial. It is often claimed that only his secretary was present at the funeral and that no clergyman attended the funeral. In contrast, Johann Georg von Eckhart (Leibniz's long-time secretary and collaborator) and Johann Hermann Vogler (his last assistant and Amanuensis ) report that the funeral took place on December 14, 1716 by the court preacher David Rupert Erythropel . Eckhart, who was appointed Hofrat and his successor as librarian and historiographer of the House of Hanover a few days after Leibniz's death , also reports that all colleagues, the officials of the court, were invited to the funeral, but only Hofrat von Eckhart himself was the only one to appear " from the stand ".

Hofrat von Eckhart had an ornament attached to the coffin that showed a one within a zero, with the inscription OMNIA AD UNUM (German: "Everything (relates) to the One"), as a reference to the binary number system developed by Leibniz and Its theological interpretation: For Leibniz the 1 stood for God and the 0 for nothing.

On behalf of Friedrich Simon Loeffler , the nephew and heir of Gottfried Wilhelm Leibniz, the librarian Daniel Eberhard Baring compiled a directory of the “Leibniz Library” privately built by the polymath.

## Last polymath

Leibniz wrote about himself in French: "Sometimes in the morning so many thoughts come to me during an hour that I am still in bed that I need the whole morning and sometimes the whole day or longer to get them clearly on paper." belongs to the early enlightenment and is often referred to as the last universal scholar . He had a strong influence on the subsequent Enlightenment , classical German philosophy, German idealism and the literature of the Weimar Classics . His discoveries in the natural sciences and his philosophical and historical writings are consulted by scholars around the world to this day. As the last great thinker, he represented the science of diverse connections and the analysis of connections, practiced before the 18th century.

Some of his research results and initiatives were:

### Philosophy, religion and number

Leibniz viewed science as a unit. His findings in integral calculus , the theory of infinite series , his novel geometry , the theories of combinatorics , the idea of ​​the fundamentals of mathematics and the calculus of probability developed in close connection with his philosophical views. The same applies to his findings on dynamics , to biological and geological conceptions, as well as to research in the field of practical politics and theoretical history .

Leibniz's philosophical work is grouped around three major problem areas: the monad theory , the concept of determination and the epistemological-logical views.

### philosophy

Illuminated quote from Leibniz at the Historical Museum in Hanover

Leibniz has continuously revised his thinking. A condensed presentation of important ideas about metaphysics can be found in his Monadology (1714) - a monad theory .

The problem of the Essais de Théodicée (1710) also appears to have been solved by Leibniz. Our world is the best of all possible worlds , it has a maximum wealth of moments and in this sense the greatest possible variety.

In his conceptual theory, Leibniz assumes that all terms can be traced back to simple, atomic concepts. He was concerned with how one could assign signs to these concepts and thus in turn derive all terms from them. This is how an ideal language can be built. Among others, the philosophers Russell and Wittgenstein took up this idea and continued it. With the Ars combinatoria (1666) Leibniz attempted to resume the heuristic project .

Text of the Leibniz quote at the Historisches Museum Hannover:

“There is no desolation, nothing sterile, nothing dead in the world; no chaos, no confusion except an apparent one; roughly as it would appear to rule in a pond if one saw a confused movement and, so to speak, a swarm of fish from a distance, without distinguishing the fish themselves "

- GWL

#### Best of all possible worlds

The famous phrase about the “best of all possible worlds” has often been misunderstood, including Voltaire parodying it in his novel Candide . The idea of ​​the " best of all possible worlds " should not naively deny or gloss over the actual and great evil in the world. Rather, Leibniz points to a necessary connection between good and bad: namely, there is good that can only be had at the price of the existence of evil. The real world is the best & a. in the sense that the good in it cannot be realized even by God with a lesser degree of evil. In addition, the “best of all possible worlds” is thought of as dynamic: it is not the current state of the world that is the best possible, but the world with its development potential is the best of all possible worlds.

It is precisely this development potential that makes it possible to improve the current state of affairs, not towards a utopian end point, but more and more, in a never-ending process of constant outbidding development.

Leibniz argues, on the one hand, that some of the evils are only apparent, or that fewer evils in one place would necessitate more in another. He also cites the diversity that defines the quality of the world, for example. But there is also a logical reason why this has to be the best of all possible worlds. For if God wants to transform a world from the possible into the real, he needs a sufficient reason because he cannot choose arbitrarily. The only criterion that qualitatively distinguishes a world from all others is to be the best. In contrast to Descartes , for example , Leibniz takes the view that God cannot create or change logical truths. God finds the sum of all possible worlds as well as mathematical theorems. He therefore has no influence on the state and events within a world. Even if he - overriding the laws of nature - works a miracle, this miracle is already fixed once and for all with the selection of the possible world.

One aspect of this is: God created the best of all possible worlds. Since he is all-powerful, all-knowing and all-good, he had to. The evils occurring in the world do not stand in the way of this. Leibniz distinguishes between three types:

1. Metaphysical evil
The metaphysical evil or misery consists in the finitude of the world. This would be unavoidable if God wanted to create a perfect world.
2. Physical evil
Suffering and pain arise out of metaphysical evil with a certain necessity , since created beings are necessarily imperfect.
3. Moral evil
A created being has the opportunity to be absent or, in theological terms, to sin because God has given him the gift of freedom .

According to Leibniz, there is no contradiction between determinism and freedom . Although every action of a person, for example, is completely immovable with the choice of the world, the fact that a person behaves in a situation like this and not otherwise is completely free (in the sense of unpredictable). That a person behaves like this (would behave like that) is precisely the reason why the world was chosen. A different behavior would be either logically impossible (not kompossibel with the rest of the world) require a morally inferior world, or would.

The explanations about the best of all possible worlds can be seen as anticipating modern modal logics (e.g. that of Saul Aaron Kripke or David Kellogg Lewis ).

#### enlightenment

Leibniz formulated the maxim of the rationality of the Enlightenment early on . Quote: “Everyone has the ability to lead a sensible life.” If religion and reason coincide, a true religion would arise. Leibniz postulated that all gifts can spoil a person, that only genuine reason is absolutely salutary for him, but that there will only be no longer any doubt if it can prove to be equally clear and certain everywhere, like arithmetic . In the wake of Pythagoras, the mathematician Leibniz was of the opinion that the deepest secrets are hidden in numbers. That is, if one could express reason with numbers, the objection would be refuted: “How do you know that your reason is better than mine? What criterion do you have for the truth? "

#### harmony

Harmony is a defining term in Leibniz's philosophy. He describes harmony as the sum of infinitely many, infinitely small units of force, so-called monads , the original components of the world substance, which were united by God and thus hold the world together.

Leibniz assumes that God created everything out of nothing ( creatio ex nihilo ) and that everything that God created is good. This leads to the conclusion that there is wonderful order everywhere. He gives the numbers as an example , as no changes have been made there.

Leibniz even wanted to use this symbol of the Christian faith to convert the Gentiles. On the other hand, Leibniz also means: "All worldly evil arises from the finite essence of nature". However, imperfection is a necessary partial evil. Ultimately, the actual world is the "best possible of all worlds". Leibniz 'popular presentation of many of his basic ideas under the title " Theodicy " treats a. a. this removal of objections alleged to be directed to God because of the imperfection of the world and the sufferings experienced.

Leibniz developed the monad theory as an alternative to contemporary trends. The philosophers of the 17th century usually either worked out a new theory of substance or they developed the atomic theory further according to modern standards. Leibniz did not satisfy either of these views. He calls the philosophy of the atomists a "lazy" philosophy, since this view, which regards the atoms as the final building blocks, does not analyze the living, changing world in depth enough. Contrary to atomistic conceptions of time and space, which compare these forms of existence of matter with an empty vessel, Leibniz advocates a dialectical conception in which space and time are relationships of order in the material world. Space is the order of things that exist at the same time, time is the order of their continuous changes.

He takes up the term monad from the Neoplatonic tradition. The term monad , "unity", comes from the Stoicheiosis theologike of the late antique philosopher Proclus .

A monad - the central concept of Leibniz's explanation of the world - is a simple, non-extensive and therefore indivisible substance that is inaccessible to external mechanical influences.

The entire universe is formed (in the spontaneously formed by the monads perceptions perceptions ab). They are a kind of spiritual atom, eternal, indivisible, unique. Leibniz thus represents a panpsychistic worldview. The idea of ​​the monad solves the problem of the interaction between spirit and matter, which arises from René Descartes ' system . It also solves the problem of isolation, which appears problematic in Baruch Spinoza's system . There individual living beings are described as merely accidental changes in the single substance . An example: A substance can exist without thinking, but thinking cannot exist without substance.

Since Leibniz idealistically solves the basic question of philosophy and for him matter is only an "otherness of the soul", he rejects the absolute character of space and time. In Leibniz's metaphysics, space and time are understood as order relationships between entities in the material world. Leibniz's theory of substance includes the possibilities of all-round developments. Although the monads are identical in their germs, they develop differently. According to Leibniz, development does not mean the creation of something fundamentally new, but only the unfolding of what is already there. Body , soul and spirit are not fundamentally different, they are just developed differently. Leibniz solves the problem of the connection between body and soul by showing that all monads, although they do not exert any mutual influence on their inner structure, work in a coordinated manner. He claims that God ensured their unity and coordinated action in the creation of the monads. He marks this state with the term “pre-established harmony”. In spite of the idealistic- teleological nature of this view, the effort can be felt to demonstrate the unity of the world and to uncover the laws that work in it.

### Legal system

In 1667 Leibniz published a text on the reform of the legal system. In it he calls for a standardization of the legal works of the Christian nations. He tried to find something true in every religion and to place this in a great harmony , in an all-embracing general religion. With these efforts he went to the level of an Erasmus of Rotterdam , who had a similar goal, namely to create a scholarly republic in which ancient and Christian elements are combined in order to promote tolerance and humanity .

Leibniz strove for peace throughout his life. In 1670 he tried to contribute to a reunion of Catholics and Protestants. Between 1679 and 1702 he negotiated with the bishops Spinola and Bossuet . Until 1706 he tried unsuccessfully to bring together at least the Protestant denominations. These efforts were based on his view that the religious community is an indispensable prerequisite for the preservation of Western culture. All his efforts failed to overcome the attachment of the deeply divided countries. Because of this, Leibniz's striving for synthesis and harmony failed .

### mathematics

#### Numbers from the spirit of religion

For Leibniz the motto was: “Without God there is nothing.” That is why he set one for God and zero for nothing. At the same time he examined the language and found that it constantly allows mistakes. This creates enormous communication problems that sooner or later lead to conflicts. Leibniz set the goal of his research to resolve these conflicts. He thought he had recognized that our thinking is actually a calculation process, which closes the circle to religiosity and that of God and nothing, of 1 and 0. Consequently, he tried to develop a reliable logical symbol language ( mathesis universalis ). To this end, he discussed the dual system accordingly: it forms the operational basis of modern computer technology. Leibniz also recognized that every object can be assigned a characteristic number, similar to the arithmetic symbols for natural numbers. With this, according to Leibniz, God wanted to show us that our minds still hold a far deeper secret, of which arithmetic is only a shadow.

#### Analysis situs

Leibniz founded a mathematics of spatial relationships, which should not be based on numbers and sizes like algebra, but on purely qualitative properties. He called his new science Analysis situs , but also used other terms such as Geometria situs , Calculus situs , Nouvelle characteristique or Analyze géometrique . This later resulted in the topology , which was developed by Johann Benedict Listing in consideration of the Leibniz analysis situs.

#### logic

Leibniz dealt intensively with logic and for the first time propagated a symbolic logic in calculus form . He did not, however, publish his logic calculus sketches; They were published very late (1840, 1890, 1903). His characteristic numbers from 1679 are an arithmetic model of the logic of Aristotle. Its main calculus, he developed into the Generales Inquisitiones of 1686. He designed the first equation there logic and headed in her nearly two centuries before the Boole -Schule the laws of Boolean Association Rules from. Within this calculation he formulated the traditional conceptual logic or syllogistics based on the logic of equations. He invented the set diagrams long before Leonhard Euler and John Venn and used them to represent the syllogistics.

The Leibniz law goes back to him.

#### calculus

During a stay in Paris from 1672 to 1676 Leibniz came into contact with leading mathematicians of his time. Without a secure theoretical basis, one learned at that time to add up infinite sequences and series . Leibniz found a criterion for the convergence of alternating series ( Leibniz criterion ), from which in particular the convergence of the so-called Leibniz series

${\ displaystyle \ sum _ {n = 0} ^ {\ infty} {\ frac {(-1) ^ {n}} {2n + 1}} = 1 - {\ frac {1} {3}} + { \ frac {1} {5}} - \ cdots}$

follows. Using geometrical considerations, he also found their limit value . By summing series, Leibniz came to integral calculus in 1675 and from there to differential calculus ; he documented his reflections in 1684 with a publication in the acta eruditorum . According to today's standards (priority of first publication) he would be considered the sole author of the calculus ; However, this interpretation is anachronistic, since scientific communication in the 17th century was primarily oral, through access to manuscripts and by correspondence. Lasting achievement of Leibniz is in particular the still common notation of differentials (with a letter "d" from Latin differentia ), differential quotients and integrals ( the integral sign is derived from the letter S from Latin summa ). ${\ displaystyle \ textstyle {\ frac {\ pi} {4}}}$ ${\ displaystyle ({\ tfrac {{\ text {d}} y} {{\ text {d}} x}})}$${\ displaystyle \ textstyle \ int {\ text {d}} x}$

##### Priority dispute

The English natural scientist Sir Isaac Newton had developed the basic features of calculus as early as 1666. However, he did not publish his results until 1687. Decades later, this resulted in what is perhaps the most famous priority dispute in the history of science. The first pamphlets in which Leibniz and Newton were accused of plagiarizing each other appeared in 1699 and 1704. In 1711 the dispute broke out in full sharpness. In 1712 the Royal Society passed an investigation report which Newton himself had fabricated; Johann I Bernoulli responded in 1713 with a personal attack on Newton. The dispute continued after Leibniz's death, and poisoned relationships between English and continental mathematicians for several generations. Above all, the development of mathematics in England, which for a long time stuck to the technically inferior Newtonian notations, was damaged. Today researchers agree that Leibniz and Newton developed their calculi independently of one another.

While working with the matrix calculation, the mathematician found the so-called Leibniz formula for calculating the determinant for a general matrix: ${\ displaystyle n \ times n}$

${\ displaystyle \ det A = \ sum _ {\ sigma \ in S_ {n}} \ left (\ operatorname {sgn} (\ sigma) \ prod _ {i = 1} ^ {n} a_ {i, \ sigma (i)} \ right)}$

He also developed the dyadic ( dual system ) with the digits 0 and 1 (dual numbers), which is of fundamental importance for modern computer technology .

### Leibniz's calculating machine

Leibniz's four-species calculating machine - original, around 1690
Dresden replica of Leibniz's calculating machine
The origin of the adding machine, the sprocket wheel , hand sketch by Leibniz

Many important inventions come from Leibniz, for example a calculating machine and inventions for the use of the wind in pit drainage in the Upper Harz mining industry . Leibniz's calculating machine (of which there are five consecutive versions) was a historic milestone in the construction of mechanical calculating machines. The staggered roller principle he invented , with which multiplications could be realized in a mechanical way, was an indispensable basic technology for over 200 years. The precision mechanical problems that had to be overcome when building such a machine were so immense, however, that there are justified doubts as to whether a fault-free machine could ever be realized during Leibniz's lifetime. An error-free replica according to Leibniz's construction plan could only be realized in 1990 by Nikolaus Joachim Lehmann (Dresden).
Quote from Leibniz:

It is unworthy to waste the time of excellent people with servile arithmetic work, because when using a machine, even the most simple-minded can safely write down the results. "

- Gottfried Wilhelm Leibniz

In a broader sense, Leibniz pioneered the calculating machine in today's sense, the computer. He discovered that arithmetic processes can be carried out much more easily with a binary number coding , and also that the principles of arithmetic can be linked with the principles of logic by means of the binary number code (see De progressione Dyadica , 1679; or Explication de l'Arithmetique Binaire , 1703). The principles researched here were only used in the construction of calculating machines 230 years later (e.g. in the Zuse Z1 ). Unlike previous inventors, Leibniz had more philosophical motives when building a calculating machine. With the much sought-after quote that “excellent people are unworthy of slaves losing hours with calculations”, a line is drawn between man and machine. The inventive spirit (freedom, spontaneity and reason) as that which is specifically human is contrasted with the mechanical and technical-natural causality. Leibniz's invention should therefore be seen closely in connection with the work on monadology that appeared around the same time , instead of in connection with practical, i.e. H. commercial, technical and mathematical interests.

#### The machina deciphratoria

Another “calculating machine” from Leibniz remained concept: the Machina deciphratoria , a cryptological device . He invented the cipher machine back in the late 1670s, but it was not until 1688 that it was described in a brief for an audience with Emperor Leopold I in Vienna. "In doing so, he anticipated the principle of the rotor key machine by Arvid Damm (1869–1927), according to which the first generation of mechanical encryption machines (from 1918) worked, by almost 200 years."

In the years 2010–2011, Nicholas Rescher reconstructed the principle from Leibniz's notes and Klaus Badur implemented the design in detail, on the basis of which the functioning device was built in 2014 by the company G. Rottstedt in Garbsen. Emperor Leopold did not consider Leibniz's offer any further, as his advisors considered their procedures (wrongly) safe.

How it works: “For the Leibniz machine, the key consists of a) an assortment of six cipher alphabets that are to be placed on the drum together with the associated deciphering alphabets; b) the indication of which of twelve possible gap gears is used; c) the starting position of this gap gear. For the six cipher alphabets you can basically choose from 26! = 1 × 2 ×… × 26 ≈ 4 × 10 26 possibilities. Realistically, the diplomat would hardly have been given more than 50 alphabet pairs in the secret case. But as long as the spy cannot get hold of the suitcase, he has to consider the full range of possibilities. And even with 50 alphabet pairs, 50! / (50 - 6)! = 11,441,304,000 options for mounting them on the drum - including the order of the strips. "

### Empirical psychology

Leibniz did not yet use the word psychologia , which was introduced by Johann Thomas Freiius , but wrote mainly in his Monadology and in his New Essays on psychological topics. In the specialist philosophical literature, however, there are hardly any references to Leibniz's area of ​​interest.

Leibniz used the terms perception and apperception to describe the transition from unnoticed sensory perception to conscious perception and its inclusion in individual (self) consciousness . This corresponds to his theory of the law of continuity of minimal changes in physics . The assumption of a continuum with certain sensory thresholds became a guiding principle of experimental psychology and psychophysics by Gustav Theodor Fechner and Wilhelm Wundt . Regarding the relationship between the soul and the physical in their parallel process ( psychophysical parallelism ), Leibniz postulated that psychological processes follow the principle of purpose ( teleology ), physical processes follow the causal principle . He wrote: “The souls act according to the laws of ends, through endeavors, ends and means. The bodies act according to the laws of causes or movements. And the two realms, that of the effective causes and that of the purposeful causes, are in harmony with one another. "

Leibniz's doctrine of principles and his doctrine of volitional activity (striving, desire), detached from the ultimate theological justifications, had a fundamental influence on the thinking and research of Wilhelm Wundt, who is internationally regarded as the most important founder of modern psychology . Leibniz coined the term perspective ( perspectivism ) using the example of different views of the same city. The willingness and ability to change perspective , d. H. Mutually complementary considerations form a basic idea of ​​Wundt's scientific theory of psychology.

### Prehistory and early history

In the dispute over the historical starting area of ​​the Germanic languages ​​or peoples, Swedish researchers such as Olof Rudbeck the Elder represented. Ä. Already in the 17th century the theory that Scandinavia was the “ original home ” of the Germanic peoples ( Gothicism ). Leibniz contradicted this theory in 1696 in his Dissertatio de origine Germanorum , where he argued - well ahead of his time - with the finding of the names of water bodies ( hydronymy ). In the scholarly dispute, which has not yet been finally resolved, a growing number of prehistorians (including Rolf Hachmann ) and linguists (including Jürgen Udolph , Wolfram Euler ) have been leaning towards the position represented by Leibniz for some time .

### Linguistics / Philology

In connection with the dispute about the origin of Germanic , Leibniz also contradicted the view held by contemporary Swedish scholars that archaic Swedish was the original form of the Germanic languages. He also rejected the then widespread view that Hebrew was the first language of all humanity. In the course of his intensive philological studies, he worked on the question of the origins of the Slavic languages, recognized the linguistic meaning of Sanskrit and was fascinated by classical Chinese .

### Paleontology and biology

When a huge prehistoric skeleton was uncovered in a quarry near Thiede , now a district of Salzgitter , in June 1692 , Leibniz used a tooth to prove that it was not the remains of a "giant" that had been found, but the skeleton of a mammoth or elephant seal have.

Johann Georg von Eckhart made the content of Protogaeae , which was only published posthumously in 1749, through his own research into the genesis of the world and communications to the French Academy. In counter course were Beringer's Lying Stones of Johann Beringer probably an intrigue of the Jesuits against advocated by Eckhart in Würzburg model of history.

Through the "Protogaea" Leibniz is considered a pioneer of caving and a co-founder of palaeontology , since he did not regard fossils as games of nature, but as fossils of earlier organisms that have disappeared or have been changed by major upheavals in other parts of the world. Leibniz also had first ideas about an evolutionary change of species and suspected, for example, that the different species of big cats could descend from a common original cat species. Some pieces from his collections have been preserved at the University of Göttingen to this day.

### Letters

Leibniz was one of the most important interdisciplinary scholars of his era. A large part of his work is documented in letters. Over 20,000 letters to Leibniz have survived from the period between 1663 and 1716, which he received from around 1,100 correspondents in 16 countries. Around 15,000 letters are documented in the Leibniz archive. His correspondents include the natural scientists Christiaan Huygens and Lambert van Velthuysen , lawyers and statesmen such as Samuel von Pufendorf , Magnus von Wedderkop or Veit Ludwig von Seckendorff , the philosophers Thomas Hobbes , Baruch de Spinoza and Jakob Thomasius and the theologian Antoine Arnauld . He was a " homo societatis ". After the invention of his calculating machine, Leibniz received a drawing from the Jesuit Joachim Bouvet , who at that time was studying the I Ching in China, among other things , and on which the arrangement of the hexagrams according to Fu Hi (mythical figure before the calendar) is shown. On this drawing Leibniz handwritten the numerical numbers corresponding to the binary code shown .

Diagram of the hexagrams of the I Ching owned by Gottfried Wilhelm Leibniz, 1701

One of the most informative sources on Leibniz's work, personal and financial circumstances and the situation at the electoral court of Hanover is the intensive correspondence with his Amanuensis Johann Friedrich Hodann (1674–1745), who was in charge of the supervision during the years when he was often absent from Hanover and management of the house in Schmiedestrasse and the gardens was transferred.

## Commemoration

### Correspondence as a UNESCO World Document Heritage

Letter from Leibniz to Kiel from March 1716 regarding a publication

The German Nomination Committee proposed Gottfried Wilhelm Leibniz's 2006 correspondence stored in the Gottfried Wilhelm Leibniz Library in Hanover for the UNESCO World Document Heritage (Memory of the World) program. In autumn 2007, the General Director of UNESCO made a final decision on the new entry in the Memory of the World Register. In doing so, UNESCO declared the correspondence to be part of world memory and therefore particularly worthy of protection.

The correspondence contains around 15,000 letters with 1,100 correspondents. It is part of the Leibniz estate kept in Hanover with around 50,000 numbers and around 200,000 sheets. The estate also includes Leibniz's library and the only surviving copy of the four-species calculating machine he designed.

### Monuments

The Leibniz monument in the courtyard of Leipzig University shows Leibniz as a larger than life statue.

In Hanover, two monuments in the public space remind of Leibniz. The Leibniz Temple in the Georgengarten was consecrated in 1790; it is the first building in Germany dedicated to a non-aristocrat. On Opernplatz there is a bronze silhouette of Leibniz's head created by Stefan Schwerdtfeger , which was inaugurated on November 27, 2008. The 2.5 m high sculpture on a granite base was donated by ten sponsors for 110,000 euros. One side depicts the Leibniz quote Unitas in multitudine (unity of diversity), the other side shows the binary number system developed by Leibniz .

### Exhibitions

• 1945, July 1 - 1946 (?): Gottfried Wilhelm Leibniz (1646–1716). Exhibition for his 300th birthday. Hanover, Lower Saxony State Library
• 1966: Gottfried Wilhelm Leibniz (1646–1716). Exhibition on the 250th anniversary of his death. Hanover, Leibnizhaus
• 1987, June 10th - July 22nd: Leibniz in Berlin. Berlin, Charlottenburg Palace . Organizer: Administration of the State Palaces and Gardens in Berlin in cooperation with the Leibniz Archive of the Lower Saxony State Library in Hanover
• 1988, June: Leibniz and Europe (exhibition on the occasion of a summit meeting of the heads of state and government of the European Community). Hanover, Lower Saxony State Library . Curator: Albert Heinemann
• 1990–2007: Gottfried Wilhelm Leibniz. The work of the great universal scholar as a philosopher, mathematician, physicist, technician (repeatedly revised traveling exhibition, which was shown a total of eleven times at home and abroad and was permanently installed at the University of Hanover in 2008 as a permanent exhibition). First exhibition: Hannover, Universität (1990). Further exhibition stations: Bonn (1990), Minden (1990), Hanover (2000), Kassel (2000), Berlin (2001), Vienna (2002), Altdorf (2005), Hanover (2006). Wolfenbüttel (2007). Curator: Erwin Stein [u. a.]
• 1996: The young Leibniz and Leipzig. Exhibition for the 350th birthday of Gottfried Wilhelm Leibniz. Leipzig, old town hall . Curator: Detlef Döring
• 1996: Gottfried Wilhelm Leibniz. An exhibition on life and work in books and documents. Cologne, university and city library
• 2006: Leibniz and his books (exhibition on the occasion of the Leibniz summer 2006). Hanover, Gottfried Wilhelm Leibniz Library - Lower Saxony State Library
• 2008 ff .: Gottfried Wilhelm Leibniz (1646–1716) (permanent exhibition that emerged from the traveling exhibition 1990–2007). Hanover, Gottfried Wilhelm Leibniz University . Curator: Erwin Stein
• 2010 ff .: Leibniz Virtuell (virtual exhibition about the life and work of GW Leibniz as part of "LeibnizCentral - The Knowledge Portal on Gottfried Wilhelm Leibniz"). Responsible: Gottfried Wilhelm Leibniz Library - Lower Saxony State Library , Hanover
• 2016, Jan. 7 - June 19: Leibniz in good company. Hanover, New Town Hall . Coproduction of the Gottfried Wilhelm Leibniz Library, the Leibniz Archive, the Hanoverian artist Tobias Schreiber, the Hanover Marketing & Tourism Society and the State Capital Hanover
• 2016, February 15 - December 31: Leibniz as a mathematician. Exhibition on the 300th anniversary of the death of Gottfried Wilhelm Leibniz (1646–1716). Würzburg, branch library of the Institute for Mathematics at the University of Würzburg . Curator: Hans-Joachim Vollrath
• 2016, April 15 - 2017, January 26: Gottfried Wilhelm Leibniz (1646–1716). Life, work, effect. An exhibition of historical books and documents on the occasion of the 300th anniversary of the death of the polymath. Jena, Thuringian University and State Library . Curators: Kirsten Gerth, Uwe B. Glatz
• 2016, June 21 - December 31: 1716 - Leibniz's last year of life. Unknown to a well-known polymath. Hanover, Gottfried Wilhelm Leibniz Library - Lower Saxony State Library . Curator: Michael Kempe
• 2016, June 22 - 2017, Jan .: II00II0III0 - Leibniz. Most beautiful of all worlds. Photo exhibition. A project by Olaf Martens. Leipzig, Old Nikolaischule
• 2016, June 30 - 2017, February 5: Leibniz and the ease of thinking. Historical models: works of art, media, visions. Nuremberg, Germanic National Museum . Curator: Frank Matthias Kammel
• 2016, July 9th - October 30th: Leibniz. The universal genius in everyday life and comics. Hannover, Wilhelm Busch - German Museum for Caricature and the Art of Drawing . Concept: Georg Ruppelt
• 2016, October 5th - 18th: At the Leibniz. About Leibniz. Math and more. Exhibition on the occasion of the 350th anniversary of the matriculation of Gottfried Wilhelm Leibniz at the University of Altdorf. Altdorf, Leibniz High School. Organizer: Leibniz-Gymnasium Altdorf
• 2016, November 11 - 2017, April 2: Leibniz - the universal genius in the "mosaic". Leipzig, German Museum of Books and Writing of the German National Library

### Others

Skull of Gottfried Wilhelm Leibniz, photo by Georg Alpers junior
Leibniz portrait on the supercomputer HLRN-III, called Gottfried, at the Hanover location of the North German Association for High and High Performance Computing

## literature

### Works

• Disputatio Metaphysica De Principio Individui . Leipzig 1663. (Together with Jakob Thomasius.) Digitalcopy ofthe SLUB -Dresden.
• Disputatio Inauguralis De Casibus Perplexis In Jure . [Altdorf] 1666. Digital copy of the SLUB-Dresden.
• Nova Methodus Discendae Docendaeque Iurisprudentiae . Frankfurt 1667. Digital copy of the SLUB-Dresden.
• Dialogus de connexione inter res et verba . 1677.
• Nova Methodus Pro Maximis Et Minimis . Leipzig 1684.
• Metaphysical treatise (original title: Discours de métaphysique ). 1686.
• Ars Combinatoria . [Jena] 1690. Digital copy of the SLUB-Dresden.
• System nouveau de la nature . 1695.
• New treatises on the human mind (original title: Nouveaux Essais sur L'entendement humain ). 1704.
• Scriptores rerum Brunsvicensium , 3 vols. Hanover 1707–1711. (Collection of sources on Guelph and Lower Saxony history published by Leibniz and Godefrid Guilelmus Leibnitius). Digital copy from ULB Düsseldorf
• Theodicy (original title: Essais de Théodicée ). Amsterdam 1710.
• The rational principles of nature and grace (original title: Principes de la nature et de la Grâce fondés en raison ). 1714.
• Protogaea or Treatise on the First Form of the Earth and the Traces of History in Monuments of Nature . Leipzig 1749 (posthumously).

#### Text output

• Gottfried Wilhelm Leibniz: All writings and letters . Published by the Prussian (now German) Academy of Sciences, 1923 - information and partly pre-editions online (will be added).
• The philosophical writings of Gottfried Wilhelm Leibniz . Published by CI Gerhardt , 7 vols., 1875–1890 (reprinted repeatedly).
• Leibniz's mathematical writings . Published by CI Gerhardt, 7 vols., 1849–1863.
• Opuscules et fragments inédits de Leibniz . Published by Louis Couturat, 1903.
• Textes Inédits . Edited by Gaston Grua. Presses Universitaires de France, Paris 1948.
• Generales inquisitiones de analysi notionum et veritatum . Edited, translated and commented by Franz Schupp. Hamburg 1982, ISBN 3-7873-0533-5 .
• Admonition to the Germans. Of German language maintenance . Unchanged reprographic reprint of the Leipzig 1916 edition. Wissenschaftliche Buchgesellschaft, Darmstadt 1967 (= Libelli , Volume 216).
• Discours sur la Theologie Naturelle des Chinois . Edited by Wenchao Li and Hans Poser . Frankfurt am Main 2002, ISBN 978-3-465-03214-4 .
• Writings on syllogistics. Latin-German . Edited by Wolfgang Lenzen. Hamburg 2019.

#### Collection of quotes

• Leibniz quotes . Edited by Annette Antoine and Annette von Boetticher . Matrix Media Verlag, Göttingen 2007.

#### Foreign language editions

• General research on the analysis of concepts and truths. Lat.- German, transl. Franz Schupp, 2nd edition. Meiner, Hamburg 1993, ISBN 978-3-7873-1142-2 .
• Specimen Dynamicum. Lat.- German, ed. & Transl. Hans Günter Dosch, Glenn W. Most , Enno Rudolph. Meiner, Hamburg 1982, ISBN 978-3-7873-0534-6 .
• Philosophical works. Translated by Artur Buchenau, Ernst Cassirer , 4 vols. Meiner, Hamburg 1996, ISBN 978-3-7873-1164-4 .
• The basics of logical calculus. Lat.-dt., Ed. & Translator Franz Schupp, Stephanie Weber. Meiner, Hamburg 2000, ISBN 978-3-7873-1601-4 .
• Monadology and other metaphysical writings Franz.-Dt., Hrsg. & Übers. Ulrich Johannes Schneider Meiner, Hamburg 2002, ISBN 978-3-7873-1606-9 .
• Theorems of Philosophy. Monadology. Ultimate truths about God, the world, the nature of the soul, man and things. Text edition German-French, transl. & Cont. German commentary by Joachim Christian Horn. Königshausen & Neumann , Würzburg 1985, ISBN 3-213-00001-9 , 2nd edition. 1997, ISBN 3-8260-1297-6 .
• Early writings on natural law. Lat.- German, with the assistance of Hans Zimmermann transl. u. ed. v. Hubertus Busche. Meiner, Hamburg 2003, ISBN 978-3-7873-1622-9 .
• Philosophical writings. Edited by Hans Heinz Holz . 4 volumes. Suhrkamp, ​​Frankfurt 1986 and others ISBN 3-518-09233-2 .
• Philosophical writings and letters 1683–1687. Edited by Ursula Goldenbaum . Berlin 1992.
• New Treatises on the Human Mind. Preface and Book 1. Translated from the French and edited by Werner Schüßler. Reclam's Universal Library , 1899; Stuttgart 1993, ISBN 3-15-001899-4 .
• Early writings on natural law. Lat./dt., Phil. Bibl. Vol. 543, ISBN 3-7873-1622-1 .
• Philosophical essays . Edited and translated by Roger Ariew and Daniel Garber. Hackett, Indianapolis 1989.
• Philosophical Papers and Letters . Ed. Leroy Loemker, 2nd edition. Reidel, Dordrecht 1969.
• Philosophical Writings . Translated and edited by Mary Morris and GHR Parkinson. Dent, London 1973.
• Logical papers . Translated and edited by GHR Parkinson. Oxford University Press , 1966
• Monadology and Other Philosophical Essays . Translated and edited by Paul Schrecker and Anne Martin Schrecker. Bobbs-Merrill, NY 1965.
• Selections. Ed. Philip P. Wiener. Charles Scribner's Sons, NY 1951.
• Philosophical Texts . Edited and translated by RS Woolhouse and Richard Francks. With introduction and notes by RS Woolhouse, Oxford UP 1998, ISBN 0-19-875153-2 .
• Confessio philosophi. The Philosopher's Creed. A dialogue. Lat.-dt., Ed. & Transl. Otto Saame, Klostermann, Frankfurt 1999, ISBN 978-3-465-02665-5 (first 1967)
• Leibniz corresponds with China. The correspondence with the Jesuit missionaries 1689–1714. Ed. Rita Widmaier, Frankfurt 1990, ISBN 978-3-465-02213-8 .
• Ars Combinatoria . Frankfurt 1690

### Introductory secondary literature

• Ernst-Eberhard Wilberg: Leibniz's calculating machine and the Julius University in Helmstedt. Braunschweig 1977 (contributions to the history of Carolo-Wilhelmina 5).
• Johann Stephan Pütter: Leibnitz 'calculating machine. In: Pütter: An attempt at an academic scholarly story from the Georg Augustus University in Göttingen. Göttingen 1765, pp. 243-246.
• B. Zimmermann: On the history of Leibniz's calculating machine. In: Science and Progress. 25 (1975) 2, Berlin 1975, pp. 76-77.
• Johann Paul Bischoff: Attempt a history of the calculating machine. Ansbach 1804. Edited by Stephan Weiß. Munich 1990. The calculating machines of Pascal, Leibniz, Poleni, Leupold, Hahn etc. are explained in detail.
• Abraham Wolf: A history of science, technology, and philosophy in the eighteenth century. London 1938. See section “Calculating machines”, pp. 654–660.
• Ludolf von Mackensen : On the history and development of the first digital 4-species calculating machine by Gottfried Wilhelm Leibniz. In: Studia Leibnitiana. Supplements. 2 (1969), pp. 34-68.
• Lehmann, Nikolaus Joachim, New experiences on the functionality of Leibniz 'calculating machine. In: Studia Leibnitiana. 25: 174-188 (1993).
• Lehmann, Nikolaus Joachim, Leibniz as inventors and designers of calculating machines. In: Science and shaping the world. Boarding school Symposium on the 350th birthday of Gottfried Wilhelm Leibniz from April 9-11, 1996 in Leipzig. Edited by Kurt Nowak… Hildesheim 1999. pp. 255–267.

### Monographs

#### biography

• GE Guhrauer : Gottfried Wilhelm Freiherr von Leibniz: a biography; to Leibniz's secular celebration; with new supplements and a register . Hildesheim: Olms
• Gerd van den Heuvel : Leibniz, Gottfried Wilhelm. In: Klaus Mlynek, Waldemar R. Röhrbein (eds.) U. a .: City Lexicon Hanover . From the beginning to the present. Schlütersche, Hannover 2009, ISBN 978-3-89993-662-9 , p. 392f.
• C. von Minutoli : Leibnitz as a war politician (1841; in: Zeitschrift für Kunst, Wissenschaft und Geschichte des Krieg, 1841; pp. 95–125) download
• Wilhelm Totok , Carl Haase : (Ed.): His life, his work, his world . Publishing house for literature and current affairs, Hanover 1966.
• Kurt Müller, Gisela Krönert: Life and work of Gottfried Wilhelm Leibniz. A chronicle. Klostermann, Frankfurt am Main 1969 ( publications of the Leibniz Archive , Volume 2).
• Eric J. Aiton : Gottfried Wilhelm Leibniz: a biography . Frankfurt a. M .: Insel, 1991 (Original edition: Leibniz. A Biography . Hilger, Bristol 1985).
• George MacDonald Ross: Gottfried Wilhelm Leibniz. Living and thinking Leibniz bookkeeper, Bad Münder 1990, ISBN 978-3-925237-14-0 .
• Gunter Quarg: Gottfried Wilhelm Leibniz (1646–1716): an exhibition on life and work in books and documents . University and City Library, Cologne 1996 (106 pages), ISBN 3-931596-08-7 ( Small publications of the University and City Library of Cologne , Volume 1).
• Reinhard Finster, Gerd van den Heuvel: Gottfried Wilhelm Leibniz. With testimonials and photo documents. 4th edition. Rowohlt, Reinbek near Hamburg 2000 (= Rowohlt's monographs, 50481), ISBN 3-499-50481-2 .
• Eike Christian Hirsch : The famous Mr. Leibniz. A biography. CH Beck, Munich 2000, ISBN 3-406-45268-X .
• Ines Böger: »A seculum ... because you want to join societies«. Presentation and analysis of Leibniz's partnership plans against the background of the European academy movement in the 17th and early 18th centuries . Herbert Utz Verlag, Munich 2001, ISBN 3-8316-0018-X .
• Heribert Nobis : Leibniz, Gottfried Wilhelm. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , pp. 834-836.
• Annette Antoine, Annette von Boetticher : Leibniz for Children , in the series Olms junior collection , [Hildesheim, Zurich, New York, NY]: Olms, 2008, ISBN 978-3-487-08820-4
• Maria Rosa Antognazza: Leibniz: an intellectual biography , Cambridge [u. a.]: Cambridge University Press, 2011, ISBN 978-1-107-62761-1
• Erwin Stein : Gottfried Wilhelm Leibniz , in Dieter Tasch , Horst-Dieter Görg (eds.): It began in Hanover ... biscuits - bread rolls - calculating machines. About personalities, traditional companies and milestones in the history of technology , with contributions by Torsten Hamacher ..., in cooperation with the Technik-Forum Hannover e. V., 1st edition, Hanover: Leuenhagen & Paris, 2011, ISBN 978-3-923976-84-3 , pp. 10-23

#### Think

• Robert M. Adams: Leibniz: Determinist, Theist, Idealist . Oxford University Press, Oxford 1998, ISBN 0-19-508460-8 .
• Maria Rosa Antognazza: Leibniz: An Intellectual Biography , Cambridge University Press 2009 (the book received the Pfizer Award )
• Horst Bredekamp : The Monad's Windows. Gottfried Wilhelm Leibniz 'Theater of Nature and Art, Akademie Verlag Berlin 2004.
• Hubertus Busche: Leibniz 'Path into Perspective Universe. A harmony in the age of calculation . Felix Meiner Verlag, Hamburg 1997, ISBN 978-3-7873-1342-6 .
• JA Cover, John O'Leary-Hawthorne: Substance and Individuation in Leibniz . Cambridge University Press, Cambridge 1999, ISBN 0-521-59394-8 .
• Aron Gurwitsch : Leibniz. Philosophy of panlogism . Walter de Gruyter, Berlin 1974, ISBN 3-11-004358-0 .
• Nicholas Jolley (Ed.): The Cambridge Companion to Leibniz . Cambridge University Press, Cambridge 1995, ISBN 0-521-36588-0 .
• M. Kulstad: Leibniz on Apperception, Consciousness, and Reflection . Philosophia Verlag, Munich 1991, ISBN 3-88405-069-9 .
• Werner Schüßler, Leibniz 'conception of the human understanding (intellectus). An investigation into the change of point of view between “système commun” and “système nouveau” and the attempt to convey them (= sources and studies on philosophy, edited by Jürgen Mittelstraß, Günther Patzig, Wolfgang Wieland, vol. 32), Berlin / New York: Walter de Gruyter 1992, XVIII, 256 pp., ISBN 3-11-013645-7
• Wolfgang Lenzen: Calculus universalis. Studies on the logic of GW Leibniz . Mentis, Paderborn 2004, ISBN 3-89785-362-0 .
• Wolfgang Lenzen: "Leibniz's Logic", in: Dov M. Gabbay, John Woods (ed.): Handbook of the History of Logic, Volume 3, The Rise of Modern Logic: from Leibniz to Frege . North-Holland 2004, ISBN 978-0-444-51611-4 , pp. 1-83.
• Michael-Thomas Liske : Gottfried Wilhelm Leibniz . Beck, Munich 2000, ISBN 978-3-406-41955-3 .
• Benson Mates : The philosophy of Leibniz. Metaphysics and language . Oxford University Press, New York 1986, ISBN 0-19-503696-4 .
• R. McRae: Leibniz: Perception, Apperception, and Thought . University of Toronto Press, Toranto 1976, ISBN 0-8020-5349-1 .
• Thomas de Padova : Leibniz, Newton and the invention of time. Piper, Munich 2013, ISBN 978-3-492-05483-6 .
• GH Parkinson: Leibniz on Human Freedom. Stuttgart 1970.
• Nicholas Rescher: Leibniz, An Introduction to his Philosophy . Basil Blackwell, Oxford 1979, ISBN 0-631-11570-6 .
• Nicholas Rescher: Leibniz's Metaphysics of Nature. A group of essays . D. Reidel, Dordrecht 1981, ISBN 90-277-1252-2 .
• Bertrand Russell: A Critical Exposition of the Philosophy of Leibniz . Routledge, London 1992 (1st edition 1900), ISBN 0-415-08296-X .
• Donald Rutherford: Leibniz and the Rational Order of Nature , Cambridge University Press, Cambridge 1995, ISBN 0-521-46155-3 .
• Thomas Sonar : The history of the priority dispute between Leibniz and Newton. Springer Verlag, Berlin 2016, ISBN 978-3-662-48861-4 .
• Manfred Wilde : Correspondents from GW Leibniz. Johann Caspar Westphal , b. November 28, 1649 in Rügenwalde / Pomerania - died March 24, 1722 in Delitzsch / Saxony . In: Studia Leibnitiana . Journal for the History of Philosophy and Science , Volume 38/39, Issue 2 (2006/2007). Published on behalf of the Gottfried Wilhelm Leibniz Society e. V., Franz Steiner Verlag, Stuttgart 2008, pp. 219-234.
• Catherine Wilson: Leibniz's Metaphysics: A historical and comparative study . Manchester University Press, Manchester 1989, ISBN 0-7190-2788-8 .
• RS Woolhouse (Ed.): Gottfried Wilhelm Leibniz. Critical Assessments . Routledge, London 1994 (4 vols.), ISBN 0-415-03808-1 .

#### reception

• Alexandra Lewendoski (ed.): Leibniz pictures in the 18th and 19th centuries. Steiner, Stuttgart 2004, ISBN 978-3-515-08401-7 .

### Fiction

• Egmont Colerus : Leibniz, the life novel of a world-spanning spirit. Paul Zsolnay Verlag, Berlin / Vienna / Leipzig 1939.
• Christa Johannsen : Leibniz. Novel of his life. 6th edition. Union-Verlag, Berlin 1976.

Commons : Gottfried Wilhelm Leibniz  - Collection of images, videos and audio files
Wikisource: Gottfried Wilhelm Leibniz  - Sources and full texts
Wikisource: Godefridus Guilielmus Leibnitius  - Sources and full texts (Latin)
Wikisource: Gottfried Wilhelm Leibniz  - Sources and full texts (French)

Works

## Individual evidence

1. Louis de Jaucourt: History of the Lord of Leibnitz and directory of his works. Verlag Heinsius, 1757, p. 1
2. ^ Rolf Schneider, Wilhelm Totok (ed.): The International Leibniz Congress in Hanover. Hanover 1968, page 46.
3. ^ “It was not merely the presence of the books but the absence of their owner” - Antognazza: Biography . 2009, p. 49 .
4. Gottfried Wilhelm Leibniz: De Arte Combinatoria . Leipzig 1666 (Latin, archive.org ).
5. Gottfried Wilhelm Leibniz. Mathematics Genealogy Project, accessed January 31, 2018 .
6. Antognazza: Biography . 2009, p. 66 .
7. The universal scholar and philosopher Gottfried Wilhelm Leibniz (1646–1716) in Mainz ( Memento from December 11, 2014 in the Internet Archive )
8. ^ List of members since 1666: Letter L. Académie des sciences, accessed on January 11, 2020 (French).
9. ^ Annette von Boetticher (Red.): Leibnizstätten and Leibniz Institutions in Hanover. In: Leibniz and Hannover - on the trail of the universal genius , ed. from the Presidium of Leibniz Universität Hannover, Hannover: [o. D., 2009], pp. 22-25; here: p. 23.
10. Annette von Boetticher (Red.): Gottfried Wilhelm Leibniz: Life, Work, Approaches to Thought. In: Leibniz and Hannover - on the trail of the universal genius , ed. from the Presidium of Leibniz Universität Hannover, Hannover: [o. D., 2009], pp. 13-19; here: p. 15.
11. Jürgen Gottschalk: Technical suggestions for improvement in the Upper Harz mining industry . In: Erwin Stein , Albert Heinekamp (ed.): Gottfried Wilhelm Leibniz - The work of the great philosopher and universal scholar as mathematician, physicist, technician. Gottfried Wilhelm Leibniz Society, Hanover 1990, ISBN 3-9800978-4-6 , pp. 62-71.
12. Peter Schulze : Rafael Levi. In: Stadtlexikon Hannover , p. 512.
13. Gerd van den Heuvel: Leibniz, Gottfried Wilhelm (see literature).
14. Antognazza: Biography . 2009, p. 283; 491 .
15. Antognazza: Biography . 2009, p. 521 .
16. cf. on this Adolf Harnack, History of the Royal Prussian Academy of Sciences in Berlin , Berlin 1900; Leibniz and his academy: selected sources on the history of the Berlin Society of Sciences 1697–1716 , ed. by Hans-Stephan Brather, Berlin 1993.
17. ^ Johann Jakob Brucker: Historia critica philosophiae a mundi incunabulis ad nostram usque aetatem deducta , Vol. V, Leipzig 1766, p. 364
18. Hans Joachim Störig: Small world history of science . Zurich 1965, p. 252
19. ^ Kuno Fischer: History of modern philosophy: Leibniz and his school . Vol. 2, Friedrich Bassermann, Mannheim 1855, p. 22
20. Wilhelm Totok, Carl Haase: Leibniz (Ed.): His life, his work, his world . Verlag für Literatur und Zeitgeschehen, Hannover 1966, p. 85
21. Eike Christian Hirsch: The famous Herr Leibniz. A biography. CH Beck, Munich 2000, p. 616, ISBN 3-406-45268-X
22. Ludwig Grote: Leibniz and his time . Carl Brandes, Hannover 1869, pp. 550ff
23. Ludwig Grote: Leibniz and his time . Carl Brandes, Hannover 1869, p. 553
24. ^ Gerhard Meyer:  Baring, Daniel Eberhard. In: New German Biography (NDB). Volume 1, Duncker & Humblot, Berlin 1953, ISBN 3-428-00182-6 , p. 589 f. ( Digitized version ).
25. Harald Siebert: Leibniz Object of the Month December 2016: Leibniz on Leibniz. In: Jahresesthema.bbaw.de. Berlin-Brandenburg Academy of Sciences , accessed on April 25, 2019.
26. ^ Theodicy, I, § 21, ed. H. Herring, Philosophische Schriften 2, Suhrkamp, ​​Frankfurt am Main 1996, p. 240ff. ( French text , German translation by Julius von Kirchmann 1879)
27. ^ Marie-Luise Heuser: The beginnings of topology in mathematics and natural philosophy. In: Topology. For the description of space in cultural and media studies. Edited by Stephan Günzel, Bielefeld (transcript) 2007, pp. 183-202.
28. ^ Marie-Luise Heuser : The beginnings of topology in mathematics and natural philosophy. In: Topology. For the description of space in cultural and media studies. Edited by Stephan Günzel, Bielefeld (transcript) 2007, page 187: “Leibniz intended a mathematics of shape in order to be able to represent the qualitative perceptions, that is, the purely spatial properties of figures, their positional relationships, angles and their mechanical movements. His new analysis should provide a method for the more adequate formalization of figures, machines and motion sequences. Leibniz was interested in methods for precise descriptions of natural bodies, e.g. B. of plants and the structure of animals to develop. Leibniz even hoped to be able to record material properties better, since the quality of the materials can be defined via their fabric or the specific shape of their sensual parts . "
29. ^ De Formae Logicae per linearum ductus. ~ 1690, published only posthumously in 1903. In: Couturat: Opuscules et fragments inedits de Leibniz. Pp. 292-321.
30. Thomas Sonar : The history of the priority dispute between Leibniz and Newton. Springer Verlag, Berlin 2016, ISBN 978-3-662-48861-4 .
31. ^ Klaus Badur: The ancestors of the Enigma and the computer. In: Spectrum of Science September 2016, pp. 76–87; it includes: Nicholas Rescher: Leibniz's The Secret Machine , pp. 84–87; here: Rescher, p. 84
33. LE Loemker: Introduction to Philosophical papers and letters: A selection. Gottfried W. Leibniz (transl. And ed., By Leroy E. Loemker). Dordrecht: Riedel (2nd ed. 1969). T. Verhave: Contributions to the history of psychology: III. GW Leibniz (1646-1716). On the Association of Ideas and Learning. Psychological Report, 1967, Vol. 20, 11-116. RE Fancher & H. Schmidt: Gottfried Wilhelm Leibniz: Underappreciated pioneer of psychology. In: GA Kimble & M. Wertheimer (eds.): Portraits of pioneers in psychology. Vol. V. American Psychological Association, Washington, DC, 2003, pp. 1-17.
34. GW Leibniz: The principles of philosophy and monadology ( Les principles de la philosophie ou la monadologie . 1714/1720). In: Thomas Leinkauf (Ed.): Leibniz . Eugen Diederichs Verlag, Munich 1996, pp. 406-424.
35. ^ Wilhelm Wundt: Leibniz on the two hundredth anniversary of his death. November 14, 1916. Leipzig: Kröner, Leipzig 1917.
36. Jochen Fahrenberg: Leibniz 'influence on Wundt's psychology, philosophy and ethics. PsyDok document server for psychology. on-line
37. Jochen Fahrenberg: Wilhelm Wundt (1832-1920). Introduction, Quotations, Reception, Commentaries, Attempts at Reconstruction . Pabst Science Publishers, Lengerich 2020, ISBN 978-3-95853-574-9 . PsyDok document server for psychology, hdl: 20.500.11780 / 3783 (PDF; 3.3 MB). 2019.
38. Dissertatio de origine Germanorum… In: Journal des Savants 1697, Berlin 1697; quoted from: Opera omnia, Vol. 4, Part 2, Genevae 1768, pp. 198-205
39. Wolfram Euler , Konrad Badenheuer : Language and Origin of the Germanic Peoples - Abriss des Proto-Germanic before the First Sound Shift , 244 pp., London / Hamburg 2009, ISBN 978-3-9812110-1-6 , pp. 43–47.
40. An overview of Leibniz 'linguistic writings can be found in: Stefan Luckscheiter: Leibniz' Schriften zur Sprachforschung. In: Wenchao Li (Ed.): Unity of Reason and Diversity of Languages (= Studia Leibnitiana - Supplementa , Volume 38), Stuttgart 2014, pp. 317–432.
41. Eike Christian Hirsch: The famous Herr Leibniz. A biography. CH Beck, Munich 2000, ISBN 3-406-45268-X , p. 275.
42. Cornelius Steckner: LIES STONE AND WORLD ARCHAEOLOGY. To commemorate the 300th anniversary of the approval of Leibniz Protogaea. In: Errors & forgeries of archeology. Herne 2018, ISBN 3-96176-030-6 , pp. 86-93.
43. A contribution to the history of palaeontology and Leibniz research ( Memento from November 28, 2012 in the Internet Archive )
44. Dt. & Latin edition of Protogaea with various articles . In: Friedrich-Wilhelm Wellmer, Mike Reich, Alexander Gehler (eds.): Gottfried Wilhelm Leibniz Protogaea sive de prima facie telluris et antiquissimae historiae vestigiis in ipsis naturae monumentis dissertatio . 1st edition. Olms-Weidmann, Hildesheim, Zurich & New York 2014, ISBN 978-3-487-15130-4 , pp. I-LXX + 1-203 .
45. ^ Mike Reich, Alexander Gehler: Gottfried Wilhelm Leibniz 'collection of geoscientific objects. A search for clues . In: Wellmer, F.-W. (Ed.): Gottfried Wilhelm Leibniz Protogaea sive de prima facie telluris et antiquissimae historiae vestigiis in ipsis naturae monumentis dissertatio . 1st edition. Olms- Weidmann, Hildesheim, Zurich & New York 2014, ISBN 978-3-487-15130-4 , pp. LIX-LXX .
46. ^ Horst Eckert: GW Leibniz - Scriptores rerum Brunsvicensium , Verlag Vittorio Klostermann, Frankfurt a. M. 1971
47. ^ Kurt Müller, Gisela Krönert: Life and Work of Gottfried Wilhelm Leibniz , Verlag Vittorio Klostermann, Frankfurt a. M. 1969
48. Hanover receives a Leibniz monument. Press release. (No longer available online.) State Capital Hanover, Mayor's Office for Press and Public Relations, October 29, 2008, archived from the original on September 15, 2012 ; Retrieved November 25, 2010 .
49. Georg Ruppelt : Leibniz Sommer ( Memento of November 4, 2016 in the Internet Archive ), leaflet (PDF document) of the Gottfried Wilhelm Leibniz Library , Hanover 2009
50. Gottfried Wilhelm Leibniz in the Ecumenical Lexicon of Saints
51. The exhibition was shown in the rooms of the Provincial Museum (today: Lower Saxony State Museum, Hanover). Compare: Gerhard Meyer: The Leibniz Exhibition of the State Library (formerly Royal and Provincial Library) in Hanover. In: Zentralblatt für Bibliothekswesen 61 (1947), pp. 93–94.
52. Accompanying publication: Weimann, Karl-Heinz: Gottfried Wilhelm Leibniz. 1646-1716. Exhibition on the 250th anniversary of his death. Hanover: Culemann, 1966. - 15 pp.
53. Later installed as a permanent exhibition; Accompanying publication: Gottfried Wilhelm Leibniz. 1646-1716. Exhibition in the Leibniz House in Hanover. Compiled by the Lower Saxony State Library, Hanover, from the holdings of the Leibniz estate it is keeping, as well as with exhibits from the Historical Museum, Hanover. Editor: Karl-Heinz Weimann. - Hanover: Lower Saxony State Library, 1983. - 16 pp.
54. Accompanying publication: Gerd van den Heuvel: Leibniz in Berlin. Exhibition in Charlottenburg Palace, June 10th - July 22nd 1987. Berlin [West]: Administration of State Palaces and Gardens [u. a.], 1987. - 69 pp.
55. Accompanying publication: Albert Heinekamp; Isolde Hein (Ed.): Leibniz and Europe. With the collaboration of Herbert Breger [u. a.]. Hanover: Schlütersche Verlagsanstalt, 1994. - 167 pages ISBN 3-87706-382-9
56. Accompanying publication: Erwin Stein; Peter Wriggers (Ed.): Gottfried Wilhelm Leibniz. The work of the great universal scholar as a philosopher, mathematician, physicist, technician. 2nd edition Hannover: Leibniz University, 2007 [first: 1990]. - 140 pp. + 8 pp. ISBN 978-3-935732-20-8
57. Accompanying publication: Detlef Döring: The young Leibniz and Leipzig. Exhibition on the 350th birthday of Gottfried Wilhelm Leibniz in Leipzig's Old Town Hall. Berlin: Akademie Verlag, 1996. - 189 pp. ISBN 978-3-05-003035-7
58. Accompanying publication: Gunter Quarg: Gottfried Wilhelm Leibniz (1646–1716). An exhibition on life and work in books and documents. Cologne: University and City Library, 1996. - 106 pp. ISBN 3-931596-08-7
59. Accompanying publication: Leibniz and his books. Catalog. Book collections from the Leibniz period in the Gottfried Wilhelm Leibniz Library. Arranged by Thomas Fuchs. With contributions by Annette von Boetticher [u. a.]. Hameln: Niemeyer, 2006. - 124 pp. ISBN 978-3-8271-8902-8
60. Website for the permanent exhibition at www.uni-hannover.de ( Memento from July 21, 2016 in the Internet Archive ). Accessed: July 21, 2016
61. Accompanying publication on www.uni-hannover.de (PDF): Erwin Stein: The Leibniz permanent exhibition of the Gottfried Wilhelm Leibniz University. - 58 p. Access: July 22, 2016
62. Website at www.leibnizcentral.de Access: July 22, 2016
63. ^ Press release from the city of Hanover . Accessed: July 21, 2016
64. Website for the exhibition at www.history.didaktik.mathematik.uni-wuerzburg.de . Accessed: July 21, 2016
65. Supplement: Hans-Joachim Vollrath: Gottfried Wilhelm Leibniz (1646–1716) as a mathematician. Explanations of the exhibition in the Institute for Mathematics at the University of Würzburg. Würzburg: [sn], 2016. - 18 pp.
66. ^ Exhibition information from the Thuringian University and State Library, Jena . Accessed: July 21, 2016
67. Accompanying publication: Sabine Wefers (Ed.): Gottfried Wilhelm Leibniz (1646–1716). Life, work, effect. In historical books and documents from the Thuringian University and State Library Jena. Edited with the collaboration of Kirsten Gerth and Uwe B. Glatz. Jena: Thuringian University and State Library, 2016. - 114 pp. ISBN 978-3-944830-82-7
68. ^ Exhibition information from the Gottfried Wilhelm Leibniz Library ( Memento from July 21, 2016 in the Internet Archive ). Accessed: July 21, 2016
69. Accompanying publication: Michael Kempe (Ed.): 1716 - Leibniz 'last year of life. Unknown to a well-known polymath. Hanover: Gottfried Wilhelm Leibniz Library, 2016. - 415 pp. ISBN 978-3-943922-15-8
70. Kulturstiftung-leipzig.de . Accessed: July 22, 2016
71. ^ Exhibition information from the Germanisches Nationalmuseum, Nuremberg ( Memento from July 21, 2016 in the Internet Archive ). Accessed: July 21, 2016
72. Accompanying publication: Frank Matthias Kammel (Ed.): Leibniz and the ease of thinking. Historical models: works of art, media, visions. Exhibition in the Germanisches Nationalmuseum from June 30, 2016 to February 5, 2017. Nuremberg: Verlag des Germanisches Nationalmuseums, 2016. - 152 pages. ISBN 978-3-946217-00-8
73. ^ Exhibition information from the German Museum for Caricature and the Art of Drawing "Wilhelm Busch", Hanover ( Memento from July 21, 2016 in the Internet Archive ). Accessed: July 21, 2016
74. Accompanying publication: Klaus D. Schleiter (Ed.): Adventure Science. The Abrafaxe on the road with Gottfried Wilhelm Leibniz. With an essay by Georg Ruppelt: Leibniz and the Abrafaxe. Berlin: MOSAIK, 2016. - 175 pp. ISBN 978-3-86462-143-7
75. ^ Website for the Leibniz exhibition at the Leibniz Gymnasium Altdorf ( Memento from January 15, 2017 in the Internet Archive ). Accessed: Oct. 26, 2016
76. Modified takeover of the Leibniz exhibition of the Museum of Caricature and Drawing (Hanover) from 2016. Press release at DNB , glossary by Dr. Georg Ruppelt, director of the Gottfried Wilhelm Leibniz Library, on the exhibition in Leipzig .
77. ^
78. Lotte Burkhardt: Directory of eponymous plant names . Extended Edition. Botanic Garden and Botanical Museum Berlin, Free University Berlin Berlin 2018. bgbm.org
79. ^ Presidium of the Leibniz University Hannover (ed.): Leibniz and Hannover - on the trail of the universal genius ( Memento from April 3, 2013 in the Internet Archive ), therein the chapter "Leibniz and the biscuit", Leibniz University Hannover, 2nd revised edition , Pp. 67-68.
80. Northern Germany's supercomputer runs on ndr.de from January 16, 2014
81. ^ Leibnizgasse in the Vienna History Wiki of the City of Vienna
82. Jens Minor: Gottfried Wilhelm Leibniz: Hidden message in the Google Doodle for the mathematician's 372nd birthday . In: GoogleWatchBlog . July 1, 2018 ( googlewatchblog.de [accessed July 1, 2018]).
83. BSB digital