Leibniz, Gottfried

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  image_name     = Gottfried Wilhelm von Leibniz.jpg |
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  image_caption   = Gottfried Wilhelm Leibniz |
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  name             = Gottfried Wilhelm Leibniz |
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name = Gottfried Wilhelm Leibniz |
  birth           = [[July 2]], [[1646]] ([[Leipzig]], [[Germany]]) |
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birth = July 2, 1646 (Leipzig, [[Germany]]) |
  death           = [[November 14]], [[1716]] ([[Hanover]], [[Germany]]) |
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death = November 14, 1716 (Hanover, Germany) |
  school_tradition = [[Continental rationalism]] |
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school_tradition = Continental [[rationalism]] |
  main_interests   = [[Metaphysics]], [[Epistemology]], [[Science]], [[Mathematics]], [[theodicy]] |
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main_interests = [[Metaphysics]], [[epistemology]], [[science]], [[mathematics]], [[theodicy]] |
  influences       = [[Plato]], [[Aristotle]], [[Ramon Llull]], [[Scholastic philosophy]], [[Rene Descartes|Descartes]], [[Christiaan Huygens]] |
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influences = [[Plato]], [[Aristotle]], Ramon Llull, [[Scholastic philosophy]], [[Rene Descartes]], [[Christiaan Huygens]] |
  influenced       = Many later mathematicians, [[Christian Wolff (philosopher)|Christian Wolff]], [[Immanuel Kant]], [[Bertrand Russell]], [[Abraham Robinson]] |
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influenced = Many later mathematicians, [[Christian Wolff (philosopher)|Christian Wolff]], [[Immanuel Kant]], [[Bertrand Russell]], Abraham Robinson |
  notable_ideas   = [[Calculus]], innate knowledge, [[optimism]], [[monad]]  |
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notable_ideas = [[Calculus]], innate knowledge, [[optimism]], monad |
 
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'''Gottfried Wilhelm Leibniz''' (also ''Leibnitz'' or ''von Leibniz'')<ref name="pronunciation">[[International Phonetic Alphabet|IPA]] pronunciation: {{IPA|/'laɪpnɪts/}}.</ref> ([[July 1]] ([[June 21]] [[Old Style and New Style dates|Old Style]]) [[1646]], [[Leipzig]] &ndash; [[November 14]] [[1716]], [[Hanover]]) was a [[Germany|German]] [[polymath]] of [[Sorbs|Sorbian]] origin, deemed a universal [[genius]] in his day and since.
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'''Gottfried Wilhelm Leibniz''' (also ''Leibnitz'' or ''von Leibniz'') (July 1, 1646 - November 14, 1716) was a German polymath, deemed a universal genius in his day and since. Educated in [[law]] and [[philosophy]], and serving as factotum to two major German noble houses, Leibniz played a major role in the European [[politics]] and [[diplomacy]] of his day. His work touched on nearly every subject imaginable, from [[logic]] and [[mathematics]] to [[civil engineering]] and politics. Philosophers today see him as representing one of the peaks of early modern [[rationalism]], with his conviction that [[reason]]ing was capable of revealing all [[truth]]s of the universe.
 
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Educated in [[law]] and [[philosophy]], and serving as [[factotum]] to two major German noble houses (one becoming the British royal family while he served it), Leibniz played a major role in the European politics and diplomacy of his day. He occupies an equally large place in both the [[history of philosophy]] and the [[history of mathematics]]. He invented [[calculus]] independently of [[Isaac Newton|Newton]], and his notation is the one in general use since. In philosophy, he is most remembered for [[optimism]], i.e., his conclusion that our universe is, in a restricted sense, the best possible one God could have made. He was, along with [[Rene Descartes|René Descartes]] and [[Baruch Spinoza]], one of the three great 17th century [[Continental rationalism|rationalists]], but his philosophy also both looks back to the [[scholastic philosophy|Scholastic]] tradition and anticipates [[logic]] and [[analytic philosophy|analysis]].
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Leibniz attempted to establish a universal, integral, and unified system of thought that can be applicable to diverse areas in order to unify all partial truths dispersed into different areas. Leibniz strove for the unity of knowledge not by reductionism but by a metaphysical approach within which harmony is established among diverse components. His thoughts contain rich innovative insights that are yet to be studied and explored today.
 
 
Leibniz also made major contributions to [[physics]] and [[technology]], and anticipated notions that surfaced much later in [[biology]], [[medicine]], [[geology]], [[psychology]], [[knowledge engineering]], and [[information science]]. Key figures in their fields submit that his writings contain anticipations of [[relativity]], [[fractal geometry]], and even [[quantum mechanics]]{{citation needed}}. <!--I, the primary author of this entry, heartily concur with your reservations about the preceding sentence. It is there only at the insistence of the Australian branch of the Howard Odum fan club.—> He also wrote on [[politics]], [[law]], [[ethics]], [[theology]], [[history]], and [[philology]], even occasional verse. His contributions to this vast array of subjects are scattered in journals and in tens of thousands of letters and unpublished manuscripts. To date, there is no complete edition of Leibniz's writings, and a complete account of his accomplishments is not yet possible.
 
  
 
==Life==
 
==Life==
The only biography on Leibniz in English is Aiton (1986). A lively short account of Leibniz’s life, one also doing fair justice to the breadth of his interests and activities, is Mates (1986: 14-35), who cites the German biographies extensively. Also see [http://www.etext.leeds.ac.uk/leibniz/leibniz.htm MacDonald Ross (1984: chpt. 1)], the chapter by Ariew in Jolley (1995), and Jolley (2005: chpt. 1). For a biographical glossary of Leibniz's intellectual contemporaries, see AG 350.
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Leibniz's life was mainly spent working for various German nobles. Though such a career may have kept him from producing the sort of grand treatise characteristic of most great early [[modern philosophy|modern philosophers]], it allowed him to travel extensively in Europe, encountering (and influencing) many of the best minds of his day.
  
 
===Coming of age===
 
===Coming of age===
Leibniz was born on July 1, 1646, the child of Friedrich Leibnütz and Catherina Schmuck. He began spelling his name "Leibniz" early in adult life, but others often referred to him as "Leibnitz," a spelling which persisted until the 20th century.
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Leibniz was born on July 1, 1646, the child of Friedrich Leibnütz and Catherina Schmuck. He began spelling his name "Leibniz" early in adult life, but others often referred to him as "Leibnitz," a spelling which persisted until the twentieth century.
 
   
 
   
When Leibniz was six years old, his father, a Professor of Moral Philosophy at the [[University of Leipzig]], died, leaving a personal library to which Leibniz was granted free access from age seven onwards. By 12, he had taught himself [[Latin language|Latin]], a language he employed freely all his life, and had begun [[Greek language|Greek]]. He entered his father's university at 14, and completed his university studies by age 20, specializing in law and mastering the standard university course of classics, logic, and scholastic philosophy. However, his education in mathematics was not up to the French and British standard of the day. In 1666, he completed his habilitation thesis (which would allow him to teach), ''On the Art of Combinations''. When [[Leipzig]] declined to assure him a position teaching law upon graduation, Leibniz submitted to the University of [[Altdorf bei Nürnberg|Altdorf]] near [[Nuremberg]] the thesis he had intended to submit at Leipzig, and obtained his doctorate in law in five months. He then declined an offer of academic appointment at Altdorf, and spent the rest of his life in the service of two major German noble families.
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When Leibniz was six years old, his father, a Professor of [[Ethics|Moral Philosophy]] at the University of Leipzig, died, leaving a personal library to which Leibniz was granted free access from age seven onwards. By age 12, he had taught himself [[Latin language|Latin]], a language he employed freely all his life, and had begun to study [[Greek language|Greek]]. He entered his father's university at 14, and completed his university studies by age 20, specializing in law and mastering the standard university course of classics, logic, and [[scholasticism|scholastic]] philosophy. However, his education in mathematics was not up to the French and British standard of the day. In 1666 he completed his habilitation thesis (which would allow him to teach), ''On the Art of Combinations''. When Leipzig declined to assure him a position teaching law upon graduation, Leibniz submitted to the University of Altdorf near [[Nuremberg]] the thesis he had intended to submit at Leipzig, and obtained his doctorate in law in five months. He then declined an offer of academic appointment at Altdorf, and spent the rest of his life in the service of two major German noble families.
  
 
===Career===
 
===Career===
The outline of Leibniz's career is as follows:
 
* 1666-74: Mainly in service to the [[Elector]] of [[Mainz]], [[Schönborn|Johann Philipp von Schönborn]], and his minister, Baron von Boineburg.
 
** 1672-76. Resides in Paris, making two important sojourns to London.
 
* 1676-1716. In service to the [[Rulers of Hanover|House of Hanover]].
 
**1677-98. Courtier, first to [[John Frederick, Duke of Brunswick-Lüneburg]], then to his son, Duke, then Elector, [[Ernest Augustus, Elector of Brunswick-Lüneburg|Ernst August of Hanover]].
 
***1687-90. Travels extensively in Germany, Austria, and Italy, researching a book the Elector has commissioned him to write on the history of the House of Brunswick.
 
**1698-1714: Courtier to Elector [[George I of Great Britain|Georg Ludwig of Hanover]].
 
***1712-14: Imperial Court Councillor at the [[Hapsburg]] court in [[Vienna]].
 
**1714-16: Georg Ludwig, upon becoming [[George I of Great Britain]], forbids Leibniz to follow him to London. Leibniz ends his days in relative neglect.
 
  
Leibniz's first position was as a salaried alchemist in [[Nuremberg]], even though he knew nothing about the subject. He soon met [[J. C. von Boineburg]], the dismissed chief minister of the [[Elector]] of [[Mainz]], [[Schönborn|Johann Philipp von Schönborn]]. Von Boineburg hired Leibniz as an assistant, and shortly thereafter reconciled with the Elector and introduced Leibniz to him. Leibniz then dedicated an essay on law to the Elector in the hope of obtaining employment. The stratagem worked; the Elector asked Leibniz to assist with the redrafting of the legal code for his Electorate. In 1669, Leibniz was appointed Assessor in the Court of Appeal. Although von Boineburg died late in 1672, Leibniz remained under the employment of his widow until she dismissed him in 1674.
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Leibniz's first position was as a salaried [[alchemy|alchemist]] in Nuremberg, an area he remained interested in for the rest of his life. He soon met J. C. von Boineburg, a diplomat of the Bishop Elector of Mainz, Johann Philipp von Schönborn. Von Boineburg hired Leibniz as an assistant, and shortly thereafter introduced Leibniz to the elector. Von Schönborn soon hired Leibniz as well as a legal and political adviser.
  
Von Boineburg did much to promote Leibniz's reputation, and the latter's memoranda and letters began to attract favorable notice. Leibniz's service to the Elector soon took on a [[diplomat]]ic role. He published an essay, under the pseudonym of a fictitious [[Poland|Polish]] nobleman, arguing (unsuccessfully) for the German candidate for the Polish crown. The main European geopolitical reality during Leibniz's adult life was the ambition of the French king, [[Louis XIV]], backed by French military and economic might. Meanwhile, the [[Thirty Years' War]] had left German-speaking Europe exhausted, fragmented, and economically backward. Leibniz proposed to protect German-speaking Europe by distracting Louis as follows. France would be invited to take [[Egypt]] as a stepping stone towards an eventual conquest of the [[Dutch East Indies]]. In return, France would agree to leave Germany and the Netherlands undisturbed. This plan obtained the Elector's cautious support. In 1672, the French government invited Leibniz to [[Paris]] for discussion, but the plan was soon overtaken by events and became moot. Napoleon's failed invasion of Egypt in 1798 can be seen as an unwitting implementation of Leibniz's plan.
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Von Boineburg did much to promote Leibniz's reputation, and the latter's memoranda and letters began to attract favorable notice. Leibniz's service to the Elector soon took on a diplomatic role. The main European geopolitical reality during Leibniz's adult life was the ambition of the French king, [[Louis XIV of France|Louis XIV]], backed by French military and economic might. This was especially worrisome for the German states, who had been left exhausted, fragmented, and economically backward by the [[Thirty Years' War]]. Leibniz helped von Boineburg devise a plan to protect German-speaking Europe by distracting Louis. France would be invited to take [[Egypt]] as a stepping-stone towards an eventual conquest of the [[Dutch East Indies]]. Having directed it's military might at Egypt, France would have too few resources to attack Germany. This plan obtained the Elector's cautious support. In 1672, Leibniz was sent to Paris to present the idea to the French, but the plan was soon overtaken by events and became moot. Napoleon's failed invasion of Egypt in 1798 can perhaps be seen as an unwitting implementation of Leibniz's plan.
  
Thus Leibniz began several years in Paris, during which he greatly expanded his knowledge of mathematics and physics, and began contributing to both. He met [[Malebranche]] and [[Antoine Arnauld]], the leading French philosophers of the day, and studied the writings of [[Descartes]] and [[Blaise Pascal|Pascal]], unpublished as well as published. He befriended a German mathematician, [[Ehrenfried Walther von Tschirnhaus]]; they corresponded for the rest of their lives. Especially fateful was Leibniz's making the acquaintance of the [[Netherlands|Dutch]] physicist and mathematician [[Christiaan Huygens]], then active in Paris. Soon after arriving in Paris, Leibniz received a rude awakening; his knowledge of mathematics and physics was spotty. With Huygens as mentor, he began a program of self-study that soon resulted in his making major contributions to both subjects, including inventing his version of the differential and integral [[calculus]].
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Thus Leibniz began several years in Paris, during which he greatly expanded his knowledge of mathematics and physics, and began contributing to both. He met [[Nicolas Malebranche]] and [[Antoine Arnauld]], the leading French philosophers of the day, and studied the writings of [[Rene Descartes]] and [[Blaise Pascal]], unpublished as well as published. He befriended a German mathematician, Ehrenfried Walther von Tschirnhaus; they corresponded for the rest of their lives. Especially fateful was Leibniz's making the acquaintance of the [[Netherlands|Dutch]] physicist and mathematician [[Christiaan Huygens]], then active in Paris. Soon after arriving in Paris, Leibniz received a rude awakening; his knowledge of mathematics and physics was spotty. With Huygens as mentor, he began a program of self-study that soon resulted in his making major contributions to both subjects, including inventing his version of the differential and integral [[calculus]].
  
When it became clear that France would not implement its part of Leibniz's Egyptian plan, the Elector sent his nephew, escorted by Leibniz, on a related mission to the British government in [[London]], early in 1673. There Leibniz made the acquaintance of [[Henry Oldenburg]] and [[John Collins (mathematician)|John Collins]]. After demonstrating to the [[Royal Society]] a calculating machine he had been designing and building since 1670, the first such machine that could execute all four basic arithmetical operations, the Society made him an external member. The mission ended abruptly when news reached it of the Elector's death, whereupon Leibniz promptly returned to Paris and not, as had been planned, to Mainz.
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In 1673 Leibniz made a brief trip to London. There he made the acquaintance of Henry Oldenburg. Oldenburg was then the secretary of the Royal Society, who was particularly impressed by a calculating machine Leibniz had invented&mdash;one that could perform all four arithmetical operations. That same year, Leibniz was elected a fellow of the Society.
  
The sudden deaths of Leibniz's two patrons in the same winter meant that Leibniz had to find a new basis for his career. In this regard, a 1669 invitation from the Duke of [[Brunswick-Lüneburg|Brunswick]] to visit Hanover proved fateful. Leibniz declined the invitation, but began corresponding with the Duke in 1671. In 1673, the Duke offered him the post of Counsellor which Leibniz very reluctantly accepted two years later, only after it became clear that no employment in Paris, whose intellectual stimulation he relished, or with the [[Hapsburg]] imperial court was forthcoming.
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When Leibniz returned to Paris, however, he found himself unemployed (both von Boineburg and von Schönborn had died by 1673). He had hoped for employment by the Paris Academy, but soon realized that it would not be forthcoming (he was finally accepted in 1700). He therefore somewhat reluctantly accepted a post as councilor at the court of Hanover for Duke Johann Friedrich of Brunswick-Lüneburg.
  
Leibniz managed to delay his arrival in Hanover until the end of 1676, after making one more short journey to London, where he was shown some of [[Newton]]'s unpublished work on the calculus. This fact was deemed evidence supporting the accusation, made decades later, that he had stolen the calculus from Newton. On the journey from London to Hanover, Leibniz stopped in [[The Hague]] where he met [[Leeuwenhoek]], the discoverer of microorganisms. He also spent several days in intense discussion with [[Spinoza]], who had just completed his masterwork, the ''[[Ethics]]''. Leibniz respected Spinoza's powerful intellect, but was dismayed by his conclusions that (in Leibniz's view) contradicted Christian orthodoxy.
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Leibniz managed to delay his arrival in Hanover until the end of 1676, after making another short journey to London. On the journey from London to Hanover, Leibniz stopped in [[The Hague]] where he met [[Anton van Leeuwenhoek]], the discoverer of microorganisms. He also spent several days in intense discussion with [[Baruch Spinoza]], who had just completed his masterwork, the ''Ethics''. Leibniz respected Spinoza's powerful intellect, but was dismayed by his conclusions that contradicted Christian orthodoxy, and found many of his proofs unsound.
  
In 1677, he was promoted, at his request, to Privy Counselor of Justice, a post he held for the rest of his life. Leibniz served three consecutive rulers of the House of Brunswick as historian, political adviser, and most consequentially, as librarian of the ducal library. He thenceforth employed his pen on all the various political, historical, and [[theological]] matters involving the House of Brunswick; the resulting documents form a valuable part of the historical record for the period.
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In the service of the House of Brunswick (also: Braunschweig), Leibniz was engaged in a wide variety of projects. He attempted a number of complicated mechanical schemes for draining a series of mines in the Harz Mountains (none of which appeared to have been successful). He was assigned the massive task of compiling a history of the Guelph lineage (of which the House of Brunswick was a part), as a means towards furthering the family's aspirations. The Duke also enlisted Leibniz's legal and philosophical expertise in attempting to reunite the Protestant churches with the Catholic Church. Finally, Leibniz began producing the first mature expressions of his philosophy (beginning with the ''Meditations on Knowledge, Truth and Ideas'' of 1684).
  
Among the few people in north Germany to warm to Leibniz were the Electress [[Sophia of Hanover]] (1630-1714), her daughter [[Sophia Charlotte of Hanover]] (1668-1705), the Queen of Prussia and his avowed disciple, and [[Caroline of Ansbach]], the consort of her grandson, the future [[George II]]. To each of these women he was correspondent, adviser, and friend. In turn, they all warmed to him more than did their spouses and the future king  [[George I of Great Britain]]. For a recent study of Leibniz's correspondence with Sophia Charlotte, see [http://www.philosophy.leeds.ac.uk/GMR/homepage/sophiec.html MacDonald Ross] (1998).
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The rest of Leibniz's life was occupied with various tasks associated with Hanover. He never produced the requested history of family, but nevertheless examined numerous archives and compiled much preparatory material. He traveled constantly to various courts throughout Europe, and was able to establish an Academy of Sciences in [[Berlin]] while initiating the formation of similar societies in [[Vienna]] and [[St. Petersburg]]. Despite a large number of municipal and legal projects, he maintained an extensive correspondence on nearly every topic imaginable (around 15,000 of his letters survive). It is therefore not surprising that his relations with his employers became somewhat strained, and when Duke Georg Ludwig was crowned George I of England, the family moved while leaving Leibniz in Hanover.
  
The population of Hanover was only about 10,000, and its provinciality eventually grated on Leibniz. Nevertheless, to be a major courtier to the House of [[Brunswick-Lüneburg|Brunswick]] was quite an honor, especially in light of the meteoric rise in the prestige of that House during Leibniz's association with it. In 1692, the Duke of Brunswick became a hereditary [[Elector]] of the [[Holy Roman Empire]]. By virtue of being a granddaughter of [[James VI of Scotland and I of England|James I]], the Electress Sophia was in the line of succession to the British throne. Moreover she was neither Catholic nor married to one. Invoking these facts, the British [[Act of Settlement]] of 1701 designated her and her descent as the royal family of the United Kingdom, once both King [[William I]] and his sister and successor, [[Queen Anne]], were dead. Leibniz played a role in the initiatives and negotiations leading up to that Act, but not always an effective one. For example, something he published anonymously in England, thinking to promote the Brunswick cause, was formally censured by the [[British Parliament]].
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The last years of Leibniz's life were not happy ones. Abandoned by the House of Hanover, he made some final attempts at completing the family history and compiling an authoritative expression of his philosophy. Neither attempt was successful. He died in November of 1716.
 
The Brunswicks tolerated the enormous effort Leibniz devoted to intellectual pursuits unrelated to his duties as a courtier, pursuits such as perfecting the calculus, writing about other mathematics, logic, physics, and philosophy, and keeping up a vast correspondence. He began working on the calculus in 1674; the earliest evidence of its use in his surviving notebooks is 1675. By 1677 he had a coherent system in hand, but did not publish it until 1684. Leibniz's most important mathematical papers were published between 1682 and 1692, usually in a journal which he and Otto Mencke founded in 1682, the [http://www.library.utoronto.ca/robarts/microtext/collection/pages/actaerud.html ''Acta Eruditorum'']. That journal played a key role in advancing his mathematical and scientific reputation, which in turn enhanced his eminence in diplomacy, history, theology, and philosophy.
 
  
The Elector [[Ernest Augustus, Elector of Brunswick-Lüneburg|Ernst August]] commissioned Leibniz to write a history of the House of [[Brunswick-Lüneburg|Brunswick]], going back to the time of [[Charlemagne]] or earlier, hoping that the resulting book would advance his dynastic ambitions. From 1687 to 1690, Leibniz traveled extensively in Germany, Austria, and Italy, seeking and finding archival materials bearing on this project. Decades went by but no history appeared; the next Elector became quite annoyed at Leibniz's apparent dilatoriness. Leibniz never finished the project, in part because of his huge output on many other fronts, but also because he insisted on writing a meticulously researched and erudite book based on archival sources, when his patrons would have been quite happy with a short popular book, one perhaps little more than a [[genealogy]] with commentary, to be completed in three years or less. They never knew that he had in fact carried out a fair part of his assigned task: when the material Leibniz had written and collected for his history of the House of Brunswick was finally published in the 19th century, it filled three volumes.
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===The Calculus Dispute===
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Leibniz is credited, along with [[Isaac Newton]], with inventing the [[infinitesimal calculus]]. According to Leibniz's notebooks, a critical breakthrough occurred on November 11, 1675, when he employed integral calculus for the first time to find the area under the function ''y = x''. He introduced several notations used to this day, for instance the integral sign ∫ representing an elongated S, from the Latin word ''summa'' and the ''d'' used for [[Differential (mathematics)|differentials]], from the Latin word ''differentia''. Leibniz did not publish any of his results until 1684 (two years prior to Newton's ''Principia''). The product rule of differential calculus is still called "Leibniz's rule."
  
In 1711, [[John Keill]], writing in the journal of the Royal Society and with Newton's presumed blessing, accused Leibniz of having plagiarized Newton's calculus. Thus began the [[Newton v. Leibniz calculus controversy|calculus priority dispute]] which darkened the remainder of Leibniz's life. A formal investigation by the Royal Society (in which Newton was an unacknowledged participant), undertaken in response to Leibniz's demand for a retraction, upheld Keill's charge. Historians of mathematics writing since 1900 or so have tended to acquit Leibniz, pointing to important differences between Leibniz's and Newton's versions of the calculus.
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Leibniz's approach to the calculus fell well short of later standards of rigor (the same can be said of Newton's). We now see a Leibniz "proof" as being in truth mostly a heuristic hodgepodge, mainly grounded in geometric intuition and an intuitive understanding of differentials. Leibniz also freely invoked mathematical entities he called infinitesimals, manipulating them freely in ways suggesting that they had paradoxical algebraic properties. [[George Berkeley]], in a tract called ''The Analyst'' and elsewhere, ridiculed this and other aspects of the early calculus, pointing out that natural science grounded in the calculus required just as big of a leap of [[faith]] as [[theology]] grounded in [[Christianity|Christian]] [[revelation]].  
 
In 1711, while traveling in northern Europe, the Russian [[Tsar]] [[Peter the Great]] stopped in Hanover and met Leibniz, who then took some interest in matters Russian over the rest of his life. In 1712, Leibniz began a two year residence in [[Vienna]], where he was appointed Imperial Court Councillor to the [[Hapsburg]]s. On the death of Queen Anne in 1714, Elector Georg Ludwig became King [[George I of Great Britain]], under the terms of the 1701 [[Act of Settlement]]. Even though Leibniz had done much to bring about this happy event, it was not to be his hour of glory. Despite the intercession of the Princess of Wales, [[Caroline of Ansbach]], George I forbade Leibniz to join him in London until he completed at least one volume of the history of the Brunswick family his father had commissioned nearly 30 years earlier. Moreover, for George I to include Leibniz in his London court would have been deemed insulting to Newton, who was seen as having won the calculus priority dispute and whose standing in British official circles could not have been higher. Finally, his dear friend and defender, the dowager Electress [[Sophia of Hanover|Sophia]], died in 1714.
 
  
When Leibniz died in 1716, he was so out of favor that neither George I (who happened to be near Hanover at the time) nor any fellow courtier other than his personal secretary attended the funeral. Even though Leibniz was a life member of the Royal Society and the Berlin Academy of Sciences, neither organization saw fit to honor his passing. His grave went unmarked for more than 50 years. Thus the indifference of official Germany and England to the passing of the most accomplished European mind since Aristotle. Leibniz was eulogized by [[Fontenelle]], before the Academie des Sciences in Paris, which had admitted him as a foreign member in 1700. The eulogy was composed at the behest of the [[Elizabeth Charlotte, Princess Palatine|Duchess of Orleans]], a niece of the Electress Sophia.
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Modern calculus emerged in the nineteenth century, and banished infinitesimals into the wilderness of obsolete mathematics (although engineers, physicists, and economists continued to use them). But beginning in 1960, Abraham Robinson showed how to make sense of Leibniz's infinitesimals, and how to give them algebraic properties free of paradox. The resulting nonstandard analysis can be seen as a great belated triumph of Leibniz's mathematical and [[ontology|ontological]] intuition.
  
Leibniz never married. He complained on occasion about money, but the fair sum he left to his sole heir, his sister's stepson, proved that the Brunswicks had, by and large, paid him well. In his diplomatic endeavors, he at times verged on the unscrupulous, as was all too often the case with professional diplomats of his day. On several occasions, Leibniz backdated and altered personal manuscripts, actions which cannot be excused or defended and which put him in a bad light during the calculus controversy. On the other hand, he was charming and well-mannered, with many friends and admirers all over Europe.
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From 1711 until his death, Leibniz's life was envenomed by a long dispute with John Keill, Newton, and others, over whether Leibniz had invented the calculus independently of Newton, or whether he had merely invented another notation for ideas that were fundamentally Newton's. Today, the predominant view is that Newton developed his calculus first, then mentioned to Leibniz several things that his new method could accomplish (without specifying anything about the method itself). Leibniz took this cue to develop his own calculus, which he published quickly, perhaps with less-than-admirable motives.
  
 
===Writings===
 
===Writings===
Leibniz wrote in three languages: scholastic Latin, French, and (least often) German. During his lifetime, he published many pamphlets and scholarly articles, but only two "philosophical" books, the ''Combinatorial Art'' and the ''[[Théodicée]]''. (He published numerous pamphlets, often anonymous, on behalf of the House of [[Brunswick-Lüneburg]], most notably the "De jure suprematum" a major consideration of the nature of [[sovereignty]]. Only one substantial book appeared posthumously, his ''[[Nouveaux essais sur l'entendement humain]],''. Only in 1895, when Bodemann completed his catalogs of Leibniz's manuscripts and correspondence, did the enormous extent of Leibniz's ''[[Nachlass]]'' become clear: about 15,000 letters to more than 1000 recipients plus more than 40,000 other items. Moreover, quite a few of these letters are of essay length. Much of his vast correspondence, especially the letters dated after 1685, remains unpublished, and much of what is published has been so only in recent decades. The amount, variety, and disorder of Leibniz's writings are a predictable result of a situation he described as follows:
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Leibniz wrote in three languages: scholastic Latin, French, and (least often) German. During his lifetime, he published many pamphlets and scholarly articles, but relatively little philosophy. Only one substantial book appeared posthumously, his ''Nouveaux essais sur l'entendement humain'' (a response to John Locke's ''Essay Concerning Human Understanding''. Only in 1895, when Bodemann completed his catalogs of Leibniz's manuscripts and correspondence, did the enormous extent of Leibniz's ''Nachlass'' become clear: about 15,000 letters to more than one thousand recipients plus more than 40,000 other items. Moreover, quite a few of these letters are of essay length. Much of his vast correspondence, especially the letters dated after 1685, remains unpublished, and much of what is published has been so only in recent decades. The amount, variety, and disorder of Leibniz's writings are a predictable result of a situation he described as follows:
<blockquote>"I cannot tell you how extraordinarily distracted and spread out I am. I am trying to find various things in the archives; I look at old papers and hunt up unpublished documents. From these I hope to shed some light on the history of the [House of] Brunswick. I receive and answer a huge number of letters. At the same time, I have so many mathematical results, philosophical thoughts, and other literary innovations that should not be allowed to vanish that I often do not know where to begin." (1695 letter to Vincent Placcius in Gerhardt, ''Philosophical Writings of Leibniz'' III: 194. Revision of translation in Mates 1986.) </blockquote>
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<blockquote>I cannot tell you how extraordinarily distracted and spread out I am. I am trying to find various things in the archives; I look at old papers and hunt up unpublished documents. From these I hope to shed some light on the history of the [House of] Brunswick. I receive and answer a huge number of letters. At the same time, I have so many mathematical results, philosophical thoughts, and other literary innovations that should not be allowed to vanish that I often do not know where to begin. (1695 letter to Vincent Placcius in Gerhardt, ''Philosophical Writings of Leibniz'' III: 194. Revision of translation in Mates 1986.) </blockquote>
  
 
The extant parts of the [http://www.leibniz-edition.de critical edition] of Leibniz's writings are organized as follows:
 
The extant parts of the [http://www.leibniz-edition.de critical edition] of Leibniz's writings are organized as follows:
Line 85: Line 74:
 
*Series 4. ''Political Writings''. 6 vols., 1667-98.
 
*Series 4. ''Political Writings''. 6 vols., 1667-98.
 
*Series 5. ''Historical and Linguistic Writings''. Inactive.
 
*Series 5. ''Historical and Linguistic Writings''. Inactive.
*Series 6. ''Philosophical Writings''. 7 vols., 1663-90, and ''[[Nouveaux essais sur l'entendement humain]]''.
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*Series 6. ''Philosophical Writings''. 7 vols., 1663-90, and ''Nouveaux essais sur l'entendement humain''.
 
*Series 7. ''Mathematical Writings''. 3 vols., 1672-76.
 
*Series 7. ''Mathematical Writings''. 3 vols., 1672-76.
 
*Series 8. ''Scientific, Medical, and Technical Writings''. In preparation.
 
*Series 8. ''Scientific, Medical, and Technical Writings''. In preparation.
  
 
Some of these volumes, along with work in progress, are available online, for free. Even though work on this edition began in 1901, only 22 volumes had appeared by 1990, in part because the only additions between 1931 and 1962 were four volumes in Series 1.
 
Some of these volumes, along with work in progress, are available online, for free. Even though work on this edition began in 1901, only 22 volumes had appeared by 1990, in part because the only additions between 1931 and 1962 were four volumes in Series 1.
 
Four important collections of English translations are W (Wiener 1951), LL (Loemker 1969), AG (Ariew and Garber 1989), and WF (Woolhouse and Francks, 1998).
 
  
 
===Posthumous reputation===
 
===Posthumous reputation===
When Leibniz died, his reputation was in decline. He was remembered for only one book, the ''Théodicée'', whose supposed central argument [[Voltaire]] was to lampoon in his ''[[Candide]]''. Leibniz had an ardent disciple, [[Christian Wolff (philosopher)|Christian Wolff]], whose dogmatic and facile outlook did Leibniz's reputation much harm. In any event, philosophical fashion was moving away from the rationalism and system building of the 17th century, of which Leibniz had been such an ardent exponent. Much of Europe came to doubt that he had invented the calculus independently of Newton, and hence his whole work in mathematics and physics was neglected. His work on law, diplomacy, and history was seen as of ephemeral interest. The vastness and richness of his correspondence went unsuspected.
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When Leibniz died, his reputation was in decline. Many thought of him primarily as the author of ''Théodicée'', whose supposed central argument [[Voltaire]] was to lampoon in his ''Candide''. Leibniz had an ardent disciple, [[Christian Wolff|Christian Wolff]], who briefly generated much enthusiasm for 'Leibnizian-Wolffian' philosophy, only to become a principal target of Kant. Much of Europe came to doubt that Leibniz had invented the calculus independently of Newton, and much of his whole work in mathematics and physics was neglected. His work on law, diplomacy, and history was seen as of ephemeral interest. The vastness and richness of his correspondence went unsuspected.
 
 
Leibniz's long march to his present glory began with the 1765 publication of the ''Nouveaux Essais'', which [[Kant]] read closely. In 1768, Dutens edited the first multi-volume edition of Leibniz's writings, followed in the 19th century by a number of editions, including those edited by Erdmann, Foucher de Careil, Gerhardt, Gerland, Klopp, and Mollat. Publication of Leibniz's correspondence with notables such as [[Antoine Arnauld]], [[Samuel Clarke]], [[Sophia of Hanover]], and her daughter [[Sophia Charlotte of Hanover]], began.
 
  
In 1900, [[Bertrand Russell]] published a study of Leibniz's metaphysics. Shortly thereafter, [[Louis Couturat]] published an important [http://philosophy2.ucsd.edu/~rutherford/Leibniz/intro.htm study] of Leibniz, and edited a volume of Leibniz's heretofore unpublished writings, mainly on logic. While their conclusions are debatable, Russell's in particular, they made Leibniz somewhat respectable among 20th century analytical and linguistic philosophers. (E.g., Leibniz's phrase ''[[salva veritate]]'' [interchangeability without loss of or compromising the truth] recurs in [[Willard Quine]]'s writings.) Nevertheless, the secondary literature on Leibniz did not really blossom until after [[WWII]]. This is especially true of English speaking countries; in Gregory Brown's [http://www.hfac.uh.edu/gbrown/philosophers/leibniz/ online bibliography,] fewer than 30 of the English language entries were published before 1946. American Leibniz studies owe much to Leroy Loemker (1904-85); see, e.g., his (1969) annotated translations and his interpretive essays included in LeClerc (1973).
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Leibniz's long march to his present glory began with the 1765 publication of the ''Nouveaux Essais'', which [[Immanuel Kant|Kant]] read closely. In 1768 Dutens edited the first multi-volume edition of Leibniz's writings, followed in the nineteenth century by a number of editions, including those edited by Erdmann, Foucher de Careil, Gerhardt, Gerland, Klopp, and Mollat. Publication of Leibniz's correspondence with notables such as [[Antoine Arnauld]], Sophia of Hanover, and her daughter Sophia Charlotte of Hanover, began.
  
Leibniz's reputation as a philosopher is now perhaps higher than at any time since he was alive because (Jolley 2005: 217-19):
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In 1900, [[Bertrand Russell]] published a study of Leibniz's metaphysics. Shortly thereafter, Louis Couturat published an important [http://philosophy2.ucsd.edu/~rutherford/Leibniz/intro.htm study] of Leibniz, and edited a volume of Leibniz's heretofore-unpublished writings, mainly on logic. While their conclusions have been debated, they made Leibniz respectable among twentieth-century analytical and linguistic philosophers. With analytic philosophy's renewed interest in metaphysics in the 1960s and 1970s, Leibniz's work has received more and more attention.
*Work in the history of 17th and 18th century [[history of ideas|ideas]] now reveals more clearly a 17th century Intellectual Revolution that preceded the better known [[industrial revolution|Industrial]] and commercial revolutions of the 18th and 19th centuries.
 
*The doctrinaire contempt for [[metaphysics]], characteristic of [[analytic philosophy|analytic]] and [[linguistic philosophy]], has faded;
 
*[[Analytic philosophy]] continues to profit from his notions of [[Identity (philosophy)|identity]], [[individuation]], and [[possible worlds]];
 
*The 17th century belief that natural science, especially [[physics]], differs from philosophy mainly in degree and not in kind, is no longer dismissed out of hand;
 
*He is now seen as a major prolongation of the mighty endeavor begun by [[Plato]] and [[Aristotle]]: the [[universe]] and man's place in it are amenable to human [[reason]].
 
  
 
==Philosopher==
 
==Philosopher==
It is very difficult to grasp Leibniz's philosophical thinking, because his philosophical writings consist mainly of a multitude of short pieces: journal articles, manuscripts published long after his death, and many letters to many correspondents. He only wrote two philosophical treatises, and the only one he published in his lifetime, the ''Théodicée'' of 1710, is as much theological as philosophical. Leibniz dated his beginning as a philosopher to his ''[[Discourse on Metaphysics]]'', which he composed in 1686 as a commentary on a running dispute between [[Malebranche]] and [[Antoine Arnauld]]. This led to an extensive and valuable correspondence with Arnauld (AG 69, LL §§36,38); it and the ''Discourse'' were not published until the 19th century. In 1695, Leibniz made his public entrée into European philosophy with a journal article titled "New System of the Nature and Communication of Substances" (AG 138, LL §47, W II.4). Over 1695-1705, he composed his ''[[New Essays on Human Understanding]]'', a lengthy commentary on [[John Locke]]'s 1690 ''[[An Essay Concerning Human Understanding]]'', but upon learning of Locke's 1704 death, lost the desire to publish it, so that the ''New Essays'' were not published until 1765. The ''[[Monadology|Monadologie]]'', composed in 1714 and published posthumously, consists of 90 aphorisms.
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There are at least three challenges in developing a plausible summary of Leibniz's philosophy. First, unlike nearly every other figure in early modern philosophy, Leibniz left no single philosophical work that can be taken as the definite expression of his main thought. Second, Leibniz's views appear differently in different places, not only because of the development of his thought, but also because he often tailored his writings to his audience. Finally, there is the fact of the vastness of the Leibnizian corpus, which is, for all intents and purposes, simply too large for any one person to adequately survey.
 
 
Leibniz met [[Spinoza]] in 1676, read some of his unpublished writings, and has since been suspected of appropriating some of Spinoza's ideas. While Leibniz admired Spinoza's powerful intellect, he was also forthrightly dismayed by Spinoza's conclusions (AG 272-84, W III.8, LL §§14,20,21), especially when these were inconsistent with Christian orthodoxy.
 
 
 
Unlike Descartes and Spinoza, Leibniz had a thorough university education in philosophy. His lifelong [[Scholastic philosophy|scholastic]] and [[Aristotle|Aristotelian]] turn of mind betrayed the strong influence of one of his [[Leipzig]] professors, [[Jakob Thomasius]], who also supervised his BA thesis in philosophy. Leibniz also eagerly read [[Francisco Suarez]], a Spanish Jesuit respected even in Lutheran universities. Leibniz was deeply interested in the new methods and conclusions of [[Descartes]], [[Huygens]], [[Newton]], and [[Boyle]], but viewed their work through a lens heavily tinted by scholastic notions. Yet it remains the case that Leibniz's methods and concerns often anticipate the [[logic]], and [[analytic philosophy|analytic]] and [[linguistic philosophy]] of the 20th century.
 
 
 
For a first introduction to Leibniz's philosophy, turn to the Introduction of an anthology of his writings in English translation, e.g., Wiener (1951), Loemker (1969a), Woolhouse and Francks (1998). Then turn to the monographs [http://www.etext.leeds.ac.uk/leibniz/leibniz.htm MacDonald Ross (1984),] and Jolley (2005). For an introduction to Leibniz's metaphysics, see the chapters by Mercer, Rutherford, and Sleigh in Jolley (1995); see Mercer (2001) for an advanced study. For an introduction to those aspects of Leibniz's thought of most value to the philosophy of logic and of language, see Jolley (1995, chpts. 7,8);  Mates (1986) is more advanced. MacRae (Jolley 1995: chpt. 6) discusses Leibniz's theory of knowledge. For glossaries of the philosophical terminology recurring in Leibniz's writings and the secondary literature, see Woolhouse and Francks (1998: 285-93) and Jolley (2005: 223-29).
 
 
 
===The Principles===
 
Leibniz variously invoked one or another of seven fundamental philosophical Principles (Mates 1986: chpts. 7.3, 9):
 
*[[Identity (mathematics)|Identity]] / [[Contradiction]]. If a proposition is true, its negation is false and vice versa.
 
*[[Identity of indiscernibles]]. Two things are identical if and only if they share the same properties.
 
*[[principle of sufficient reason|Sufficient Reason]]. "There must be a sufficient reason [often known only to God] for anything to exist, for any event to occur, for any truth to obtain." (LL 717).
 
*[[Pre-established harmony]]. See Jolley (1995: 129-31), Woolhouse and Francks (1998), and Mercer (2001).
 
*[[Continuum mechanics|Continuity]]. ''Natura non saltum facit''. A mathematical analog to this principle would go as follows. If a function describes a transformation of something to which continuity applies, its domain and range are both dense sets.
 
*[[Optimism]]. "God assuredly always chooses the best." (LL 311).
 
*[[Plenitude principle|Plenitude]].
 
 
 
He would on occasion propose a rationale for a specific principle, but often took them for granted. For a precis of what Leibniz meant by these and other Principles, see Mercer (2001: 473-84). For a classic discussion of [[principle of sufficient reason|sufficient reason]] and [[Plenitude principle|plenitude]], see Lovejoy (1957).
 
 
 
===The Monads===
 
Leibniz's best known contribution to [[metaphysics]] is his theory of [[monad]]s, as exposited in his ''Monadologie.'' Monads are to the mental realm what [[atom]]s are to the physical. (Curiously, Leibniz argued that matter was infinitely divisible, thus denying that atoms exist.) Monads are the ultimate elements of the [[universe]], and are also entities of perception. The [[monad]]s are "substantial forms of being" with the following properties: they are eternal, indecomposable, individual, subject to their own laws, un-interacting, and each reflecting the entire universe in a [[pre-established harmony]] (a historically important example of [[panpsychism]]). Monads are centers of [[force]]; substance is force, while [[space]], [[matter]], and [[motion]] are merely phenomenal.
 
 
 
The [[ontology|ontological]] essence of a monad is its irreducible simplicity. Unlike [[atom]]s, monads possess no material or spatial character. They also differ from atoms by their complete mutual independence, so that interactions among monads are only apparent. Instead, by virtue of the principle of [[pre-established harmony]], each monad follows a preprogrammed set of "instructions" peculiar to itself, so that a monad "knows" what to do at each moment. (These "instructions" may be seen as analogs of the [[scientific law]]s governing [[subatomic particle]]s.) By virtue of these intrinsic instructions, each monad is like a little mirror of the universe. Monads need not be "small"; e.g., each human being constitutes a monad, in which case [[free will]] is problematic. [[God]], too, is a monad, and [[existence of God|God's existence]] can be inferred from the harmony prevailing among all other monads; God wills the [[pre-established harmony]].
 
 
 
Monads are purported to solve the problematic:
 
*Interaction between [[mind]] and [[matter]] arising in the system of [[Descartes]];
 
*Lack of [[individuation]] inherent to the system of [[Spinoza]], which represent individual creatures as merely [[accident|accidental]].
 
 
 
The monadology was thought arbitrary, even eccentric, in Leibniz's day and since. It now seems less so, in the light of key notions in contemporary physics such as [[field (physics)|field]], and the [[action at a distance (physics)|action at a distance]] and [[entanglement]] characterizing [[quantum mechanics]].
 
 
 
===Theodicy and optimism===
 
The ''Théodicée'' tries to justify the apparent imperfections of the world by claiming that it is optimal among all possible worlds. It must be the best possible and most balanced world, because it was created by a perfect God. Rutherford (1998) is a detailed scholarly study of Leibniz's theodicy.
 
  
The statement that "we live in the best of all possible worlds" drew scorn, most notably from [[Voltaire]], who lampooned it in his comic novel ''[[Candide]]'' by having the character ''[[Pangloss|Dr. Pangloss]]'' (a parody of Leibniz) repeat it like a [[mantra]]. Thus the adjective "panglossian", describing one so naive as to believe that the world about us is the best possible one.
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Despite these challenges, certain themes are particularly noteworthy, both because they recur in what seem to be Leibniz's main philosophical works, and because of their distinctive influence on later philosophers.
  
The mathematician [[Paul du Bois-Reymond]], in his "Leibnizian Thoughts in Modern [[Science]]," wrote that Leibniz thought of God as a [[mathematician]].<blockquote> "As is well known, the theory of the [[maxima]] and [[minima]] of [[Function (mathematics)|functions]] was indebted to him for the greatest progress through the discovery of the method of [[tangent]]s. Well, he conceives God in the creation of the world like a mathematician who is solving a minimum problem, or rather, in our modern phraseology, a problem in the [[calculus of variations]] - the question being to determine among an [[infinite]] number of possible worlds, that for which the sum of necessary [[evil]] is a minimum."</blockquote>
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Unlike [[Rene Descartes|Descartes]] and [[Baruch Spinoza|Spinoza]], Leibniz had a thorough university education in [[ancient philosophy|ancient]] and [[scholastic philosophy]], one which he took seriously. His writings show his desire to find some element of truth in each of the various positions. Whereas the Cartesians were eager to abandon the Aristotelian notion of forms, Leibniz attempted to integrate talk of forms into a [[metaphysics]] derived from that of Descartes.
  
A cautious defense of Leibnizian [[optimism]] would invoke certain scientific principles that emerged in the two centuries since his death and that are now thoroughly established: the [[principle of least action]], the [[conservation of mass]], and the [[conservation of energy]]. Recent scientific developments enable a bolder defense. The [[solar system]] appears to have a number of fortuitous characteristics that support [[Earth]]'s long lived and melioristic [[biosphere]]: the Earth is rich in [[metal]]s, is of the right size and distance from the [[sun]], and has the right [[rotation period]] and axis tilt. The [[Moon]] and Jupiter have sizes and [[orbit]]s enabling them to shield the Earth from [[bolide]] impacts; for whatever reason, such impacts have been happily rare since life emerged; and so on (Ward & Brownlee, 2000; Morris 2003: chpts. 5,6).
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===Logic===
  
Bolder yet is a defense of [[optimism]] that invokes the [[Anthropic Principle]]. Contemporary physics can be seen as grounded in the numerical values of a handful of [[fundamental physical constants|dimensionless constants]], the best known of which are the [[fine structure constant]] and the ratio of the [[rest mass]] of the [[proton]] to the [[electron]]. Were the numerical values of these constants to differ by a few percent from their observed values, it is likely that the resulting universe would be incapable of harboring [[complexity]]. Our universe is "best" in the sense that it is capable of supporting [[complexity|complex]] structures such as [[galaxy|galaxies]], [[star]]s, and, ultimately, life on Earth.
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Leibniz is probably the most important logician between Aristotle and 1847, when [[George Boole]] and [[Augustus De Morgan]] each published books that began modern [[formal logic]]. Leibniz enunciated the principal properties of what we now call conjunction, disjunction, negation, identity, set, inclusion, and the empty set. He also provided some groundwork for what would become epistemic and [[modal logic]]. Yet Leibniz's vision of logic was far grander than that of any modern logician; perhaps grander than that of any other figure in the history of philosophy.
  
===Symbolic thought===
 
 
Leibniz had a remarkable faith that a great deal of human reasoning could be reduced to calculations of a sort, and that such calculations could resolve many differences of opinion:
 
Leibniz had a remarkable faith that a great deal of human reasoning could be reduced to calculations of a sort, and that such calculations could resolve many differences of opinion:
<blockquote>"The only way to rectify our reasonings is to make them as tangible as those of the Mathematicians, so that we can find our error at a glance, and when there are disputes among persons, we can simply say: Let us calculate [''calculemus''], without further ado, to see who is right." (''The Art of Discovery'' 1685, W 51) </blockquote>
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<blockquote>The only way to rectify our reasonings is to make them as tangible as those of the Mathematicians, so that we can find our error at a glance, and when there are disputes among persons, we can simply say: Let us calculate [''calculemus''], without further ado, to see who is right. (''The Art of Discovery'' 1685, W 51) </blockquote>
Leibniz's [[calculus ratiocinator]], which very much brings [[symbolic logic]] to mind, can be viewed as a way of making calculations of this sort feasible. Leibniz wrote memoranda (many of which are translated in Parkinson 1966) that can now be read as groping attempts to get symbolic logic—and thus his ''calculus''—off the ground. But Gerhard and Couturat did not publish these writings until after modern formal logic had emerged in Frege's ''[[Begriffsschrift]]'' and in various writings by [[Charles Peirce]] and his students in the 1880s, and hence well after [[George Boole|Boole]] and [[Augustus De Morgan|De Morgan]] began that logic in 1847.
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He proposed the creation of a ''characteristic universalis'' or "universal characteristic," built on an alphabet of human thought in which each fundamental concept would be represented by a unique "real" character.
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<blockquote>It is obvious that if we could find characters or signs suited for expressing all our thoughts as clearly and as exactly as arithmetic expresses numbers or geometry expresses lines, we could do in all matters ''insofar as they are subject to reasoning'' all that we can do in arithmetic and geometry. For all investigations which depend on reasoning would be carried out by transposing these characters and by a species of calculus. (''Preface to the General Science'', 1677. Revision of Rutherford's translation in Jolley 1995, 234. Also W I.4) </blockquote>
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More complex thoughts would be represented by combining in some way the characters for simpler thoughts. Leibniz saw that the uniqueness of prime factorization suggests a central role for [[prime number]]s in the universal characteristic.
  
Leibniz thought [[symbol]]s very important for human understanding. He attached so much importance to the invention of good notations that he attributed to this alone the whole of his discoveries in mathematics. His notation for the [[infinitesimal calculus]] affords a splendid example of his skill in this regard. [[Charles Peirce]], a 19th century pioneer of [[semiotics]], shared Leibniz's passion for symbols and notation, and his belief that these are essential to a well-running logic and mathematics.
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An example of what Leibniz envisioned is as follows: say that the concept 'man' is composed of the more simple concepts 'rational' and 'animal.' Say that to each of the latter a prime number is assigned: 3 and 5. By multiplying these together, we get a number for 'man': 15. If one later wanted to know whether men were animals, all one would have to do is to find whether the number for the later was a factor of the former. Leibniz envisioned such a means of evaluating the truth of propositions as extending to much more contentious propositions, and thus as a promising means for resolving disputes. Of course, matters would become much more complex with more complex concepts, and one can see Leibniz's interests in establishing academies and developing calculating machines as aimed in this direction.
  
But Leibniz took his speculations much further. Defining a [[Grapheme|character]] as any written sign, he then defined a "real" character as one that represents an idea directly and not simply the word embodying the idea. Some real characters, such as the notation of logic, serve only to facilitate reasoning. Many characters well-known in his day, including [[Ancient Egypt|Egyptian]] [[hieroglyphic]]s, [[Chinese character]]s, and the symbols of [[astronomy]] and [[chemistry]], he deemed not real, however Loemker, who translated some of Leibniz's works into English said that the symbols of chemistry were real characters so there is disagreement among Liebniz scholars on this point.<!--is this paragraph correct up to this point?—> Instead, he proposed the creation of a ''[[characteristica universalis]]'' or "universal characteristic," built on an [[alphabet of human thought]] in which each fundamental concept would be represented by a unique "real" character.
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Much of Leibniz's philosophy makes use of two logical-metaphysical principles whose names he coined. Though these principles are present in earlier philosophers, Leibniz makes the most explicit use of them of anyone up to his time.
<blockquote>"It is obvious that if we could find characters or signs suited for expressing all our thoughts as clearly and as exactly as arithmetic expresses numbers or geometry expresses lines, we could do in all matters ''insofar as they are subject to reasoning'' all that we can do in arithmetic and geometry. For all investigations which depend on reasoning would be carried out by transposing these characters and by a species of calculus." (''Preface to the General Science'', 1677. Revision of Rutherford's translation in Jolley 1995: 234. Also W I.4) </blockquote>
 
More complex thoughts would be represented by combining in some way the characters for simpler thoughts. Leibniz saw that the uniqueness of [[prime factorization]] suggests a central role for [[prime numbers]] in the universal characteristic, a striking anticipation of [[Gödel numbering]]. Granted, there is no intuitive or [[mnemonic]] way to number any set of elementary concepts using the prime numbers.
 
  
Because Leibniz was a mathematical novice at the time he first wrote about the ''characteristic'', at first he did not conceive it as an [[algebra]] but rather as a [[universal characteristic|universal language]] or script. Only in 1676 did he conceive of a kind of "algebra of thought," modeled on and including conventional algebra and its notation. The resulting ''characteristic'' was to include a logical calculus, some combinatorics, algebra, his ''analysis situs'' (geometry of situation) discussed in 3.2, a universal concept language, and more.  
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*Identity of indiscernibles: Two things are identical if and only if they share the same properties.
 +
*Principle of Sufficient Reason: There must be a sufficient reason, often known only to God, for anything to exist, for any event to occur, for any truth to obtain.
  
What Leibniz actually intended by his  [[characteristica universalis]] and [[calculus ratiocinator]], and the extent to which modern formal [[logic]] does justice to the calculus, may perhaps never be unambiguously established. A good introductory discussion of the "characteristic" is Jolley (1995: 226-40). An early yet still classic discussion of the "characteristic" and "calculus" is Couturat (1901: chpts. 3,4).  
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Both of these principles correspond closely to aspects of Leibniz's metaphysics.
  
The importance of the ''characteristica'' and ''calculus'' goes beyond their value for understanding Leibniz's legacy, and extends to [[mathematics]], [[modernity]], the European [[Age of Enlightenment|Enlightenment]], and, more controversially, even to [[postmodern]] theory. The ''characteristica'' and ''calculus'' are also possible ways in which Leibniz's thinking can contribute to contemporary thinking in [[thermodynamics]], [[biology]], [[climate change]], and [[resource policy]], and consequently how [[ethics]] and [[metaphysics]] can meaningfully engage with such currently topical issues. Moreover, computer [[software]] employing networks of block diagrams and pictograms to generate the mathematics and [[kinetics]] of [[ecology|ecological]], thermodynamic, and dynamic [[socioeconomic]] systems, all appear to aim at formal systems of the sort Leibniz dreamed about.
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===The Monads===
 
+
Leibniz's best known contribution to [[metaphysics]] is his theory of monads, as exposited in his ''Monadology''. Roughly speaking, monads are to the mental realm what atoms were seen as being to the physical. While making use of the analogy with atoms, however, Leibniz argued that matter was infinitely divisible, and so denied that physical atoms exist (Leibniz in fact sometimes argued first that there must be monads, and then established that such monads could not be extended). Monads, along with God, are the ultimate elements of the universe. The monads are "substantial forms of being" with the following properties: they are eternal, indecomposable, individual, active, subject to their own laws, causally independent of one another, and each reflecting the entire universe in a pre-established harmony.
===Formal logic===
 
Leibniz is the most important logician between Aristotle and 1847, when [[George Boole]] and [[Augustus De Morgan]] each published books that began modern formal logic. Leibniz enunciated the principal properties of what we now call [[logical conjunction|conjunction]], [[disjunction]], [[negation]], [[Identity (mathematics)|identity]], set [[subset|inclusion]], and the [[empty set]]. The principles of Leibniz's logic and, arguably, of his whole philosophy, reduce to two:
 
 
 
#All our ideas are compounded from a very small number of simple ideas, which form the [[alphabet of human thought]].
 
#Complex ideas proceed from these simple ideas by a uniform and symmetrical combination, analogous to arithmetical multiplication.
 
 
 
With regard to (1), the number of simple ideas is much greater than Leibniz thought. As for (2), logic can indeed be grounded in a symmetrical combining operation, but that operation is analogous to either of addition or multiplication. The formal logic that emerged early in the 20th century  also requires, at minimum, unary [[negation]] and [[quantification|quantified]] [[variable]]s ranging over some [[universe of discourse]].
 
 
 
Leibniz published nothing on formal logic in his lifetime; most of what he wrote on the subject consists of working drafts [[Louis Couturat]] found in the [[Nachlass]] and published in 1903. Selections from this volume have been translated into English, mainly by Parkinson (1966) and Loemker (1969). Our present understanding of Leibniz the logician emerges mainly from the work of Wolfgang Lenzen, beginning around 1980; for a summary, see [http://www.philosophie.uni-osnabrueck.de/Woods.htm Lenzen (2004).] 
 
 
 
[[Charles Peirce]], [[Hugh MacColl]], [[Frege]], and [[Bertrand Russell]] all shared Leibniz's dream of combining symbolic logic, mathematics, and philosophy. The culmination of Leibniz's approach to logic is, arguably, the algebraic logic of [[Ernst Schröder]] and the [[modal logic]] founded by [[Clarence Irving Lewis]]. For an example of how present-day work in logic and metaphysics can draw inspiration from, and shed light on, Leibniz's thought, see Zalta (2000).
 
 
 
==Mathematician==
 
Although the mathematical notion of [[Function (mathematics)|function]] was implicit in trigonometric and logarithmic tables, which existed in his day, Leibniz was the first, in 1692 and 1694, to employ it explicitly, to denote any of several geometric concepts derived from a curve, such as [[abscissa]], [[ordinate]], [[tangent]], [[chord (geometry)|chord]], and the perpendicular (Struik 1969: 367). In the 18th century, "function" lost these geometrical associations.
 
 
 
Leibniz was the first to see that the coefficients of a system of [[linear equation]]s could be arranged into arrays, now called [[determinant]]s, which can be manipulated to find the solution of the system, if any. This method was later called [[Cramer's Rule]]. Leibniz's discovery of [[Boolean algebra]] and of [[symbolic logic]] was discussed in the preceding section.
 
 
 
A comprehensive scholarly treatment of Leibniz's mathematical writings has yet to be written, perhaps because Series 7 of the Academy edition is very far from complete.
 
 
 
===Calculus===
 
Leibniz is credited, along with [[Isaac Newton]], with inventing the [[infinitesimal calculus]]. According to Leibniz's notebooks, a critical breakthrough occurred on [[November 11]], [[1675]], when he employed integral calculus for the first time to find the area under the function ''y&nbsp;=&nbsp;x''. He introduced several notations used to this day, for instance the [[integral sign]] &int; representing an elongated S, from the Latin word ''summa'' and the ''d'' used for [[Differential (mathematics)|differentials]], from the Latin word ''differentia''. Leibniz did not publish any of his results until 1684. For an English translation of this paper, see Struik (1969: 271-84), who also translates parts of two other key papers by Leibniz on the calculus. The [[product rule]] of [[differential calculus]] is still called "Leibniz's rule."
 
 
 
Leibniz's approach to the calculus fell well short of later standards of rigor (the same can be said of Newton's). We now see a Leibniz "proof" as being in truth mostly a [[heuristic]] hodgepodge, mainly grounded in geometric intuition and an intuitive understanding of [[differentials]]. Leibniz also freely invoked mathematical entities he called [[infinitesimal]]s, manipulating them freely in ways suggesting that they had [[paradox]]ical [[algebra]]ic properties. [[George Berkeley]], in a tract called ''The Analyst'' and elsewhere, ridiculed this and other aspects of the early calculus, pointing out that natural science grounded in the calculus required just as big of a leap of [[faith]] as [[theology]] grounded in [[Christianity|Christian]] [[revelation]].
 
 
 
The calculus as we now know it emerged in the 19th century, thanks to the efforts of [[Cauchy]], [[Riemann]], [[Weierstrass]], and others, who based their work on a rigorous notion of [[Limit (mathematics)|limit]] and on a precise understanding of the [[real number]]s. Their work banished infinitesimals into the wilderness of obsolete mathematics (although engineers, physicists, and economists continued to use them). But beginning in 1960, [[Abraham Robinson]] showed how to make sense of Leibniz's infinitesimals, and how to give them algebraic properties free of paradox. The resulting [[nonstandard analysis]] can be seen as a great belated triumph of Leibniz's mathematical and [[ontology|ontological]] intuition.
 
 
 
From 1711 until his death, Leibniz's life was envenomed by a long dispute with John Keill, [[Newton]], and others, over whether Leibniz had invented the calculus independently of Newton, or whether he had merely invented another notation for ideas that were fundamentally Newton's. Hall (1980) gives a thorough scholarly discussion of the [[Newton v. Leibniz calculus controversy|calculus priority dispute]].
 
 
 
===Topology===
 
Leibniz was the first to employ the term ''analysis situs'' (LL §27), later employed in the 19th century to refer to what is now known as [[topology]]. There are two takes on this situation. On the one hand, Mates (1986: 240), citing a 1954 paper in German by [[Freudenthal]], argues as follows:
 
<blockquote>"Although for [Leibniz] the situs of a sequence of points is completely determined by the distance between them and is altered if those distances are altered, his admirer [[Euler]], in the famous 1736 paper solving the [[Seven Bridges of Konigsberg|Konigsberg Bridge Problem]] and its generalizations, used the term ''geometria situs'' in such a sense that the situs remains unchanged under topological deformations. He mistakenly credits Leibniz with originating this concept. ...it is sometimes not realized that Leibniz used the term in an entirely different sense and hence can hardly be considered the founder of that part of mathematics."</blockquote>
 
 
 
Hirano (1997) argues differently, quoting Mandelbrot (1977: 419) as follows:
 
 
 
<blockquote>"...To sample Leibniz' scientific works is a sobering experience. Next to calculus, and to other thoughts that have been carried out to completion, the number and variety of premonitory thrusts is overwhelming. We saw examples in 'packing,'... My Leibniz mania is further reinforced by finding that for one moment its hero attached importance to geometric scaling. In "Euclidis Prota"..., which is an attempt to tighten Euclid's axioms, he states,...: 'I have diverse definitions for the straight line. The straight line is a curve, any part of which is similar to the whole, and it alone has this property, not only among curves but among sets.' This claim can be proved today."</blockquote>
 
 
 
Thus Mandelbrot's well-known fractal geometry drew on Leibniz's notions of self-similarity and the principle of continuity: ''natura non facit saltus''. We also see that when Leibniz wrote, in a metaphysical vein, that  "the straight line is a curve, any part of which is similar to the whole..." he was anticipating topology by more than two centuries. As for "packing," Leibniz told to his friend and correspondent [[Des Bosses]] to imagine a circle, then to inscribe within it three congruent circles with maximum radius; the latter smaller circles could be filled with three even smaller circles by the same procedure. This process can be continued infinitely, from which arises a good idea of self-similarity. Leibniz's improvement of Euclid's axiom contains the same concept.
 
 
 
==Scientist and engineer==
 
Leibniz's writings are currently discussed, not only for their anticipations and possible discoveries not yet recognized, but as ways of advancing present knowledge. Much of his writing on physics is included in Gerhardt's ''Mathematical Writings''. His writings on other scientific and technical subjects are mostly scattered and relatively little known, because the Academy edition has yet to publish any volume in its Series ''Scientific, Medical, and Technical Writings'' .
 
 
 
===Physics===
 
Leibniz contributed a fair amount to the statics and dynamics emerging about him, often disagreeing with [[Descartes]], [[Newton]] and their followers. He devised a new theory of [[motion]] ([[dynamics]]) based on [[kinetic]] and potential energy. While he may have been Newton's peer as co-discoverer of the calculus, he was not in Newton's league as a physicist and may even deserve to be ranked below his mentor Huygens. An important example of Leibniz's mature physical thinking is his ''Specimen Dynamicum'' of 1695. (AG 117, LL §46, W II.5) On Leibniz and physics, see the chapter by Garber in Jolley (1995) and Wilson (1989).
 
 
 
Until the discovery of subatomic particles and the [[quantum mechanics]] governing them, many of Leibniz's speculative ideas about aspects of nature not reducible to statics and dynamics made little sense. For instance, he anticipated [[Einstein]] by arguing, against [[Newton]], that [[space]], [[time]] and [[motion]] are relative, not absolute. [[Leibniz's rule]] in interacting theories plays a role in [[supersymmetry]] and in the lattices of [[quantum mechanics]]. His [[principle of sufficient reason]] has been invoked in recent [[cosmology]], and his [[identity of indiscernibles]] in [[quantum mechanics]], a field some even credit him with having anticipated in some sense.  Those who advocate [[digital philosophy]], a recent direction in cosmology, claim Leibniz as a precursor.
 
 
 
====The ''vis viva''====
 
:''See main article: [[Conservation of energy#Historical development|Conservation of energy: Historical development]].''
 
 
 
Leibniz 's ''vis viva'' (Latin for ''living force'') is an invariant mathematical characteristic of certain mechanical systems (see AG 155-86, LL §§53-55, W II.6-7a). It can be seen as a special case of the [[conservation of energy]]. Here too his thinking gave rise to another regrettable nationalistic dispute. His "vis viva" was seen as rivaling the [[conservation of momentum]] championed by Newton in England and by [[Descartes]] in France; hence [[academics]] in those countries tended to neglect Leibniz's idea. [[Engineer]]s eventually found "vis viva" useful when making certain [[calculation]]s, so that the two approaches eventually were seen as complementary.
 
 
 
===Other natural science===
 
By proposing that the earth has a molten core, he anticipated modern [[geology]]. In [[embryology]], he was a preformationist, but also proposed that organisms are the outcome of a combination of an infinite number of possible microstructures and of their powers. In the [[life sciences]] and [[paleontology]], he revealed an amazing transformist and intuition, fueled by his study of comparative anatomy and fossils. He worked out a primal organismic theory. On Leibniz and biology, see Loemker (1969a: VIII). In [[medicine]], he exhorted the physicians of his time — with some results — to ground their theories in detailed comparative observations and verified experiments, and to distinguish firmly scientific and metaphysical points of view.
 
 
 
===Social science===
 
In [[psychology]] he anticipated the distinction between [[conscious]] and [[unconscious]] states. On Leibniz and psychology, see Loemker (1969a: IX). In public health,  he advocated establishing a medical administrative authority, with powers over [[epidemiology]] and [[veterinary medicine]]. He worked to set up a coherent medical training programme, oriented towards public health and preventive measures. In economic policy, he proposed tax reforms and a national insurance scheme, and discussed the balance of trade. He even proposed something akin to what much later emerged as [[game theory]]. In [[sociology]] he laid the ground for [[communication theory]].
 
 
 
===Technology===
 
In 1906, Gerland published a volume of Leibniz's writings bearing on his many practical inventions and engineering work. To date, few of these writings have been translated into English. Nevertheless, it is well understood that Leibniz was a serious inventor, engineer, and applied scientist, with great respect for practical life. Following the motto ''theoria cum praxis'', he urged that theory be combined with practical application, and thus has been claimed as the father of [[applied science]]. He designed wind-driven propellers and water pumps, mining machines to extract ore, hydraulic presses, lamps, submarines, clocks, etc. With [[Denis Papin]], he invented a [[steam engine]]. He even proposed a method for desalinating water. He struggled, 1680-85, to overcome the chronic flooding that afflicted the ducal silver mines in the Harz Mountains, but his efforts were not crowned with success. (Aiton 1985: 107-114, 136)
 
 
 
====Information technology====
 
Leibniz may have been the first computer scientist and information theorist. Early in life, he discovered the [[binary number]] system (base 2), the one subsequently employed on all computers, then revisited that system throughout his career. On Leibniz and binary numbers, see Couturat (1901: 473-78). Leibniz anticipated Lagrangian interpolation and [[algorithmic information theory]]. His [[calculus ratiocinator]] anticipated aspects of the [[universal Turing machine]]. In 1934, [[Norbert Wiener]] claimed to have found in Leibniz's writings a mention of the concept of [[feedback]], central to Wiener's later [[cybernetics|cybernetic]] theory.
 
 
 
In 1671, Leibniz began to invent a machine that could execute all four arithmetical operations, gradually improving it over a number of years. This machine attracted fair attention and was the basis of his election to the [[Royal Society]] in 1673. A number of such machines were made during his years in Hanover, by a craftsman working under Leibniz's supervision. It was not an unambiguous success because it did not fully mechanize the operation of carrying. Couturat (1901: 115) reported finding an unpublished note by Leibniz, dated 1674, describing a machine capable of performing some algebraic operations.
 
 
 
Leibniz was groping towards hardware and software concepts worked out much later by [[Charles Babbage]] and [[Ada Lovelace]], 1830-45. In 1679, while mulling over his binary arithmetic, Leibniz imagined a machine in which binary numbers were represented by marbles, governed by a rudimentary sort of punched cards.[http://www.edge.org/discourse/schirrmacher_eurotech.html] Modern electronic digital computers replace Leibniz's marbles moving by gravity with shift registers, voltage gradients, and pulses of electrons, but otherwise they run roughly as Leibniz envisioned in 1679. Davis (2000) discusses Leibniz's prophetic role in the emergence of calculating machines and of formal languages.
 
 
 
===The librarian===
 
In his capacity as librarian of the ducal libraries in [[Hanover]] and [[Wolfenbuettel]], Leibniz effectively became one of the founders of [[library science]].[http://members.tripod.com/ClintonGreen/universal.html#6] The latter library was enormous for its day, as it contained more than 100,000 volumes, and Leibniz helped design a new building for it, believed to be the first building explicitly designed to be a library. He also designed a book [[library classification|indexing system]] in ignorance of the only other such system then extant, that of the [[Bodleian Library]] at [[Oxford University]]. He also called on publishers to distribute abstracts of all new titles they produced each year, in a standard form that would facilitate indexing. He hoped that this abstracting project would eventually include everything printed from his day back to [[Gutenberg]]. Neither proposal met with success at the time, but something like them became standard practice among English language publishers during the 20th century, under the aegis of the [[Library of Congress]] and the [[British Library]].
 
 
 
He called for the creation of an [[empirical]] [[database]] as a means of furthering all the sciences. His [[characteristica universalis]], [[calculus ratiocinator]], and a "community of minds", intended, among other things, bringing political and religious unity to Europe, can be seen as distant unwitting anticipations of artificial languages (e.g., [[Esperanto]] and its rivals), [[symbolic logic]], even the [[World Wide Web]].
 
 
 
===Advocate of scientific societies===
 
Leibniz emphasized that [[research]] was a collaborative endeavor. Hence he warmly advocated the formation of national scientific societies along the lines of the British Royal Society and the French Academie Royale des Sciences. More specifically, in his correspondence and travels he urged the creation of such societies in Dresden, Saint Petersburg, Vienna, and Berlin. Only one such project came to fruition; in 1700, the [[Berlin Academy of Sciences]] was created. Leibniz served as its first President , for life,and drew up its first statutes. That Academy evolved into the German Academy of Sciences, the publisher of the ongoing critical edition of his works. On Leibniz’s projects for scientific societies, see Couturat (1901: App. IV).
 
 
 
==Lawyer, moralist, theologian==
 
No philosopher has ever had as much experience with practical affairs of state as Leibniz, [[Marcus Aurelius]] possibly excepted. Leibniz's writings on law, ethics, and politics (e.g., AG 19, 94, 111, 193; Riley 1988; LL §§2, 7, 20, 29, 44, 59, 62, 65; W I.1, IV.1-3) were long overlooked by English speaking scholars but this has changed of late; see (in order of difficulty) Jolley (2005: chpt. 7), Gregory Brown's chapter in Jolley (1995), Hostler (1975), and Riley (1996).
 
 
 
While Leibniz was no apologist for absolute monarchy a la [[Hobbes]], or for tyranny in any form, neither did he echo the political and constitutional views of his contemporary [[John Locke]], views invoked in support of democracy, first in 18th century America and subsequently elsewhere. The following excerpt from a 1695 letter to Baron J. C. Boineburg's son Philipp is very revealing of Leibniz's political sentiments:
 
<blockquote>"As for.. the great question of the power of sovereigns and the obedience their peoples owe them, I usually say that it would be good for princes to be persuaded that their people have the right to resist them, and for the people, on the other hand, to be persuaded to obey them passively. I am, however, quite of the opinion of [[Grotius]], that one ought to obey as a rule, the evil of revolution being greater beyond comparison than the evils causing it. Yet I recognize that a prince can go to such excess, and place the well-being of the state in such danger, that the obligation to endure ceases. This is most rare, however, and the theologian who authorizes violence under this pretext should take care against excess; excess being infinitely more dangerous than deficiency." (LL: 59, fn 16. Translation revised.)</blockquote>
 
 
 
Leibniz foresaw the European Union. In 1677, he (LL: 58, fn 9) called for a European confederation, governed by a council or senate, whose members would represent entire nations and would be free to vote their consciences. Europe would adopt a uniform religion. He reiterated these proposals in 1715.
 
 
 
Most of the secondary literature on Leibniz the [[theology|theologian]] is in French. On Leibniz and the concept of [[God]], see Blumenfeld's chapter in Jolley (1995). Although Leibniz's writings very freely invoked God, and discussed [[Christian]] [[theology]] with great assurance, he was never seen at Sunday services during the last two decades of his life, and declined to take [[Eucharist|Communion]] on his deathbed. Consequently, his fellow Hanoverians suspected him of [[atheism]], and much of Europe also did so after his death. In fact, Leibniz still comes off as far more religious than [[Descartes]] the tepid [[Roman Catholicism|Catholic]], [[Spinoza]] the [[Jew]] expelled from his synagogue, [[Locke]] the suspected [[Socinian]], and [[Hobbes]] the near-atheist.
 
 
 
===Ecumenism===
 
Leibniz devoted considerable intellectual and diplomatic effort to what would now be called [[ecumenism|ecumenical]] endeavor, seeking to reconcile first the [[Roman Catholic]] and [[Lutheran]] churches, later the Lutheran and [[Reformed]] churches. In this respect, he followed the example of his early patrons, Baron von Boineburg and the Duke [[John Frederick, Duke of Brunswick-Lüneburg|John Frederick]], both cradle Lutherans who converted to Catholicism as adults, who did what they could to encourage the reunion of the two faiths, and who warmly welcomed such endeavors by others. (The House of [[Brunswick-Lüneburg|Brunswick]] remained Lutheran because the Duke's children did not follow their father.) These efforts included corresponding with the French bishop [[Bossuet]], and involved Leibniz in a fair bit of theological controversy. He evidently thought that the thoroughgoing application of reason would suffice to heal the breach caused by the [[Reformation]].
 
 
 
==Philologist==
 
Leibniz was an avid student of languages, eagerly latching on to any information about [[vocabulary]] and [[grammar]] that came his way. He refuted the belief, widely held by Christian scholars in his day, that [[Hebrew language|Hebrew]] was the primeval language of the [[human race]]. He also refuted the argument, advanced by Swedish scholars in his day, that some sort of proto-[[Swedish language|Swedish]] was the ancestor of the [[Germanic languages]]. He puzzled over the origins of the [[Slavic languages]], was aware of the existence of [[Sanskrit]], and was fascinated by classical Chinese. Scholarly appreciation of Leibniz the [[philologist]] is hampered by the fact that the first volume of the Academy edition series "Historical and Linguistic Writings" has yet to appear.
 
 
 
==Sinophile==
 
Leibniz was perhaps the first major European intellect to take a close interest in [[China|Chinese]] civilization, which he knew by corresponding with, and reading other work by, European Christian missionaries posted in China. He concluded that Europeans could learn much from the [[Confucianism|Confucian]] ethical tradition. He mulled over the possibility that the [[Chinese character]]s were an unwitting form of his [[Characteristica universalis|universal characteristic]]. He noted with fascination how the [[I Ching]] hexagrams correspond to the [[binary numbers]] from 0 to 111111, and mistakenly concluded that this mapping was evidence of major Chinese accomplishments in the sort of philosophical mathematics he admired.
 
  
On Leibniz, the I Ching, and binary numbers, see Aiton (1985: 245-48). Leibniz's writings on Chinese civilization are collected and translated in Cook and Rosemont (1994), and discussed in Perkins (2004).
+
The ontological essence of a monad is its irreducible simplicity. Unlike extended substances as conceived by Descartes, monads possess no material or spatial character. They also differ from Cartesian extended substance by their complete mutual independence, so that interactions among monads are only apparent. Instead, by virtue of the principle of pre-established harmony (see below), every modification of any monad in the universe was matched by some corresponding modification in every other monad in the universe. Each monad can then be said to 'mirror' the entire universe.
  
==Universal genius==
+
===Pre-Established Harmony===
The following episode from the life of Leibniz illustrates the breadth of his genius, and the difficulties awaiting those who try to come to terms with it. While making his grand tour of European [[archive]]s to research the Brunswick family history he never completed, Leibniz stopped in [[Vienna]], May 1688 – February 1689, where he did much [[law|legal]] and [[diplomacy|diplomatic]] work for the Brunswicks. He visited [[mine]]s, talked with mine [[engineering|engineers]], and tried to negotiate export contracts for [[lead]] from the ducal mines in the [[Harz mountains]]. His proposal that the streets of Wien be lit with lamps burning [[rapeseed oil]] was implemented. During a formal audience with the [[Hapsburg|Austrian Emperor]] and in subsequent memoranda, he advocated reorganizing the Austrian economy, reforming the coinage of much of central Europe, negotiating a [[Concordat]] between the [[Habsburg]]s and the [[Holy See|Vatican]], and creating an imperial research library, official archive, and public insurance fund. He wrote and published an important paper on [[mechanics]].
+
Leibniz believed that each monad was metaphysically independent of everything else in the universe, save [[God]]. This independence is both [[ontology|ontological]] and [[causality|causal]]. As long as God continues to preserve it, any particular monad could continue to exist while all others are destroyed. Further, no monad is capable of causally affecting another monad, or being affected.
  
Leibniz also wrote a short paper, first published by [[Louis Couturat]] in 1903, later translated as LL 267 and WF 30, summarizing his views on [[metaphysics]]. The paper is undated; that he wrote it while in Vienna was determined only in 1999, when the ongoing [http://www.leibniz-edition.de critical edition] finally published Leibniz's philosophical writings for the period 1677-90. Couturat's reading of this paper was the launching point for much 20th century thinking about Leibniz, especially among [[analytic philosophy|analytic philosophers]]. But after a meticulous study of all of Leibniz's philosophical writings up to 1688 — a study the 1999 additions to the critical edition made possible — Mercer (2001) begged to differ with Couturat's reading; the jury is still out.
+
Such a view raises an obvious question: if (as Leibniz held) my mind and body are both monads, why is it that they appear to affect each other. For instance, when I choose to raise my arm, my arm lifts, and when I jam my toe, I experience a certain sensation. [[Descartes]] had explained such correlations in terms of genuine causal interaction (via the pineal gland). Many of Descartes' successors found such interaction unintelligible, though, and by Leibniz's time the main alternative was the occasionalist view most prominently advanced by [[Nicolas_Malebranche|Malebranche]]. Occasionalism held that, in all such cases, the causal force came directly from God.
  
Leibniz was not devoid of humor and imagination; see W IV.6 and LL § 40. Also see a curious passage titled "Leibniz's Philosophical Dream," first published by Bodemann in 1895 and translated on p. 253 of Morris, Mary, ed. and trans., 1934. ''Philosophical Writings''. Dent & Sons Ltd.
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Leibniz, however, claimed that occasionalism made causation unacceptably mysterious, with the universe filled with 'miracles.' He saw the Principle of Sufficient Reason as requiring that every change a [[substance]] undergoes be explicable in terms of that substance's own essence. On this basis, he formulated an alternative he dubbed 'pre-established harmony.' This view held that, at creation, each substance was essentially programmed by God to undergo all the changes it would ever go. Throughout its existence, then, its changes were merely the result of the unfolding of its nature. In virtue of this, all substances are coordinated in their changes, such that it appears to them that interaction is occurring.
  
==Notes==
+
===[[Theodicy]] and Optimism===
<div class="references-small">
+
The ''Théodicée'' tries to justify the apparent imperfections of the world by claiming that it is optimal among all possible worlds. It must be the best possible and most balanced world, because it was created by a perfect God, who is omnipotent and omnibenevolent. It is on this basis that Leibniz believed all monads were coordinated, despite their causal independence. Moreover, many facts about the world could only be known via considering the Principle of Sufficient Reason in combination with knowledge that this world is the best possible.
<references />
 
</div>
 
  
 +
The statement that "we live in the best of all possible worlds" drew scorn, most notably from [[Voltaire]], who lampooned it in his comic novel ''Candide'' by having the character Dr. Pangloss (a parody of Leibniz) repeat it like a mantra. Thus the adjective "panglossian," describing one so naive as to believe that the world about us is the best possible one.
  
==Works==
+
== References ==
AG = Ariew & Garber (1989). LL = Loemker (1969). W = Wiener (1951). Woolhouse and Francks (1998) = WF.
+
===Works by Leibniz ===
 +
AG = Ariew & Garber 1989. LL = Loemker 1969. W = Wiener 1951. WF = Woolhouse and Francks 1998.
  
 
The ongoing critical edition of all of Leibniz's writings is [http://www.leibniz-edition.de ''Sämtliche Schriften und Briefe''.]
 
The ongoing critical edition of all of Leibniz's writings is [http://www.leibniz-edition.de ''Sämtliche Schriften und Briefe''.]
  
Selected works; major ones in bold. The year shown is usually the year in which the work was completed, not of its eventual publication.
+
The year shown is usually the year in which the work was completed, not of its eventual publication.
* 1666. ''De Arte Combinatoria'' (On the Art of Combination). Partially translated in LL §1 and Parkinson (1966).
+
* 1666. ''De Arte Combinatoria'' (On the Art of Combination). Partially translated in LL §1 and Parkinson 1966.
 
* 1671. ''Hypothesis Physica Nova'' (New Physical Hypothesis). LL §8.I (part)
 
* 1671. ''Hypothesis Physica Nova'' (New Physical Hypothesis). LL §8.I (part)
* 1684. ''Nova methodus pro maximis et minimis'' (New Method for maximums and minimums). Translation in Struik, D. J., 1969. ''A Source Book in Mathematics, 1200-1800''. Harvard Uni. Press: 271-81.
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* 1684. ''Nova methodus pro maximis et minimis'' (New Method for maximums and minimums). Translation in Struik, D. J., 1969. ''A Source Book in Mathematics, 1200-1800''. Harvard University Press: 271-81.
* 1686. ''[[Discourse on Metaphysics (book)|Discours de métaphysique]]''. Martin and Brown (1988). [http://www.earlymoderntexts.com/pdf/leibdm.pdf Jonathan Bennett's translation.] AG 35, LL §35, W III.3, WF 1.
+
* 1686. ''Discours de métaphysique]]''. Martin and Brown (1988). [http://www.earlymoderntexts.com/pdf/leibdm.pdf Jonathan Bennett's translation.] AG 35, LL §35, W III.3, WF 1.
 
* 1705. ''Explication de l'Arithmétique Binaire'' (Explanation of Binary Arithmetic). Gerhardt, ''Mathematical Writings'' VII.223.
 
* 1705. ''Explication de l'Arithmétique Binaire'' (Explanation of Binary Arithmetic). Gerhardt, ''Mathematical Writings'' VII.223.
* 1710. '''Théodicée'''. Farrer, A.M., and Huggard, E.M., trans., 1985 (1952). [http://www.gutenberg.org/etext/17147 ''Theodicy''.] Open Court. W III.11 (part).
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* 1710. ''Théodicée''. Farrer, A.M., and Huggard, E.M., trans., 1985 (1952). [http://www.gutenberg.org/etext/17147 ''Theodicy''.] Open Court. W III.11 (part).
* 1714. ''[[Monadology|Monadologie]]''. [[Nicholas Rescher]], trans., 1991. ''The Monadology: An Edition for Students''. Uni. of Pittsburg Press. [http://www.earlymoderntexts.com/pdf/leibmon.pdf Jonathan Bennett's translation.] [http://www.rbjones.com/rbjpub/philos/classics/leibniz/monad.htm Latta's translation.] AG 213, LL §67, W III.13, WF 19.
+
* 1714. ''Monadology''. Nicholas Rescher, trans., 1991. ''The Monadology: An Edition for Students''. University of Pittsburgh Press. [http://www.earlymoderntexts.com/pdf/leibmon.pdf Jonathan Bennett's translation.] [http://www.rbjones.com/rbjpub/philos/classics/leibniz/monad.htm Latta's translation.] AG 213, LL §67, W III.13, WF 19.
* 1765. ''[[Nouveaux essais sur l'entendement humain]]''. Completed 1704. Remnant, Peter, and Bennett, Jonathan, trans., 1996. ''New Essays on Human Understanding''. Cambridge Uni. Press. W III.6 (part). [http://www.earlymoderntexts.com/f_leibniz.html Jonathan Bennett's translation.]
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* 1765. ''Nouveaux essais sur l'entendement humain''. Completed 1704. Remnant, Peter, and Bennett, Jonathan, trans., 1996. ''New Essays on Human Understanding''. Cambridge University Press. W III.6 (part). [http://www.earlymoderntexts.com/f_leibniz.html Jonathan Bennett's translation.]
  
 
Collections of shorter works in translation:
 
Collections of shorter works in translation:
* Ariew, R., and Garber, D., 1989. ''Leibniz: Philosophical Essays''. Hackett.
+
* Ariew, R., and D. Garber. 1989. ''Leibniz: Philosophical Essays''. Hackett Publishing Company. Paperback edition. ISBN 0872200620
 
* Bennett, Jonathan. [http://www.earlymoderntexts.com/f_leibniz.html Various texts.]
 
* Bennett, Jonathan. [http://www.earlymoderntexts.com/f_leibniz.html Various texts.]
* Cook, Daniel, and Rosemont, Henry Jr., 1994. ''Leibniz: Writings on China''. Open Court.
+
* Cook, Daniel J. and Henry Rosemont, Jr. 1994. ''Leibniz: Writings on China''. Open Court. ISBN 0812692500
* Dascal, Marcelo, 1987. ''Leibniz: Language, Signs and Thought''. John Benjamins.
+
* Dascal, Marcelo. 1987. ''Leibniz: Language, Signs and Thought''. John Benjamins. ISBN 9027232806
* Loemker, Leroy E., 1969 (1956). ''Leibniz: Philosophical Papers and Letters''. Reidel.
+
* Loemker, Leroy E. 1956. ''Leibniz: Philosophical Papers and Letters''. Second edition, 1975. Springer. ISBN 902770693X
* Martin, R.N.D., and Brown, Stuart, 1988. ''Discourse on Metaphysics and Related Writings''. St. Martin's Press.
+
* Martin, R.N.D., and Stuart Brown. 1988. ''Discourse on Metaphysics and Related Writings''. Reprint edition, 1990. Manchester University Press. ISBN 0719017025
* Parkinson, G.H.R., 1966. ''Leibniz: Logical Papers.'' Oxford Uni. Press.
+
* Parkinson, G.H.R., 1966. ''Leibniz: Logical Papers.'' New York: Oxford University Press. ISBN 0198243065
* ------, and Morris, Mary, 1973. '''Leibniz: Philosophical Writings''. London: J M Dent & Sons.  
+
* Parkinson, G.H.R. and Mary Morris. 1973. '''Leibniz: Philosophical Writings''. Reprint edition, 1991. London: J M Dent & Sons. ISBN 0460870459
* Riley, Patrick, 1988 (1972). ''Leibniz: Political Writings''. Cambridge Uni. Press.
+
* Riley, Patrick. 1972. ''Leibniz: Political Writings''. Second edition, 1988. Cambridge University Press. ISBN 052135899X
 
* Rutherford, Donald. [http://philosophy2.ucsd.edu/~rutherford/Leibniz/translat.htm Various texts.]
 
* Rutherford, Donald. [http://philosophy2.ucsd.edu/~rutherford/Leibniz/translat.htm Various texts.]
* Strickland, Lloyd, 2006. ''Shorter Leibniz Texts''. Continuum Books. [http://www.leibniz-translations.com/ Online.]  
+
* Strickland, Lloyd (trans.). 2006. ''Shorter Leibniz Texts''. Continuum Books. ISBN 0826489516. [http://www.leibniz-translations.com/ Online.]
* Wiener, Philip, 1951. ''Leibniz: Selections''. Scribner. Regrettably out of print and lacks index.
+
* Wiener, Philip. 1951. ''Leibniz: Selections''. Scribner.  
* Woolhouse, R.S., and Francks, R., 1998. ''Leibniz: Philosophical Texts''. Oxford Uni. Press.
+
** <small>Regrettably, out of print and lacks index.</small>
 +
* Woolhouse, R.S., and R. Francks. 1998. ''Leibniz: Philosophical Texts''. New York: Oxford University Press. ISBN 0198751532
  
 
Donald Rutherford's [http://philosophy2.ucsd.edu/~rutherford/Leibniz/edition.htm online bibliography.]
 
Donald Rutherford's [http://philosophy2.ucsd.edu/~rutherford/Leibniz/edition.htm online bibliography.]
  
==Secondary literature==
+
===Secondary literature===
Introductory:
+
====Introductory====
*Jolley, Nicholas, 2005. ''Leibniz''. Routledge.
+
*Jolley, Nicholas. 2005. ''Leibniz''. Routledge. ISBN 041528337X
*MacDonald Ross, George, 1984. ''[http://www.etext.leeds.ac.uk/leibniz/leibniz.htm Leibniz]''. Oxford Uni. Press.  
+
*MacDonald Ross, George. 1984. ''[http://www.etext.leeds.ac.uk/leibniz/leibniz.htm Leibniz]''. Oxford University Press.  
*[[W. W. Rouse Ball]], 1908. [http://www.maths.tcd.ie/pub/HistMath/People/Leibniz/RouseBall/RB_Leibnitz.html ''A Short Account of the History of Mathematics''], 4th ed. (see [[Talk:Gottfried Leibniz|Discussion]])
+
*W. W. Rouse Ball, 1908. [http://www.maths.tcd.ie/pub/HistMath/People/Leibniz/RouseBall/RB_Leibnitz.html ''A Short Account of the History of Mathematics'']
 +
====Intermediate====
 +
*Aiton, Eric J. 1985. ''Leibniz: A Biography''. Taylor and Francis. ISBN 0852744706
 +
*Hall, A. R. 1980. ''Philosophers at War: The Quarrel between Newton and Leibniz''. New edition, 2002. Cambridge University Press. ISBN 052152489X
 +
*Hostler, J. 1975. ''Leibniz's Moral Philosophy''. UK: Duckworth. US: Barnes and Noble. ISBN 0064929930
 +
*Jolley, Nicholas (ed.). 1995. ''The Cambridge Companion to Leibniz''. Cambridge University Press. ISBN 0521367697
 +
*LeClerc, Ivor (ed.). 1973. ''The Philosophy of Leibniz and the Modern World''. Vanderbilt University Press. ISBN 0826511813
 +
*Loemker, Leroy. 1969a. "Introduction" to his ''Leibniz: Philosophical Papers and Letters''. Reidel: 1-62.
 +
*Lovejoy, Arthur O. 1957 (1936). "Plenitude and Sufficient Reason in Leibniz and Spinoza" in his ''The Great Chain of Being''. Harvard University Press: 144-82. Reprinted in H. G. Frankfurt (ed.), 1972. ''Leibniz: A Collection of Critical Essays''. Doubleday. ISBN 0385033087
 +
*MacDonald Ross, George. 1999. "Leibniz and Sophie-Charlotte" in S. Herz, C. M. Vogtherr, and F. Windt (eds.), ''Sophie Charlotte und ihr Schloß''. München: Prestel: 95–105. [http://www.philosophy.leeds.ac.uk/GMR/homepage/sophiec.html English translation.]
 +
*Perkins, Franklin. 2004. ''Leibniz and China: A Commerce of Light''. Cambridge University Press. ISBN 0521830249
 +
*Riley, Patrick. 1996. ''Leibniz's Universal Jurisprudence: Justice as the Charity of the Wise''. Harvard University Press. ISBN 0674524071
 +
====Advanced====
 +
*Adams, Robert M. 1994. ''Leibniz: Determinist, Theist, Idealist''. Reprint edition, 1998. Oxford University Press. ISBN 0195126491
 +
*Couturat, Louis. 1901. ''La Logique de Leibniz''. Paris: Felix Alcan. [http://philosophy2.ucsd.edu/~rutherford/Leibniz/intro.htm Donald Rutherford's English translation in progress.]
 +
*Ishiguro, Hide. 1972. ''Leibniz's Philosophy of Logic and Language''. Second edition, 1991. Cambridge University Press. ISBN 0521377811
 +
*Lenzen, Wolfgang. 2004. [http://www.philosophie.uni-osnabrueck.de/Woods.htm "Leibniz's Logic,"] in D. Gabbay and J. Woods (eds.), ''Handbook of the History of Logic, Vol. 3''. North Holland: 1-84.
 +
*Mates, Benson. 1986. ''The Philosophy of Leibniz: Metaphysics and Language''. Reprint edition, 1989. Oxford University Press. ISBN 0195059468
 +
*Mercer, Christia. 2001. ''Leibniz's metaphysics: Its Origins and Development''. Paperback edition, 2006. Cambridge University Press. ISBN 0521029929
 +
*Robinet, André. 2000. ''Architectonique disjonctive, automates systémiques et idéalité transcendantale dans l'oeuvre de G.W. Leibniz: Nombreux textes inédits''. [http://www.vrin.fr/html/main.htm Vrin]
 +
*Rutherford, Donald. 1995. ''Leibniz and the Rational Order of Nature''. New paperback edition, 1998. Cambridge University Press. ISBN 0521597374
 +
*Wilson, Catherine. 1989. ''Leibniz's Metaphysics''. Princeton University Press. ISBN 0691073597
 +
*Woolhouse, R. S. (ed.). 1993. ''G. W. Leibniz: Critical Assessments'', 4 vols. Routledge. ISBN 041503809X
 +
**<small>A remarkable and regrettably expensive one-stop collection of many valuable articles.</small>
  
Intermediate:
+
==External links==
*Aiton, Eric J., 1985. ''Leibniz: A Biography''. Hilger (UK).
+
All links retrieved June 27, 2017.
*Hall, A. R., 1980. ''Philosophers at War: The Quarrel between Newton and Leibniz''. Cambridge Uni. Press.
 
*Hostler, J., 1975. ''Leibniz's Moral Philosophy''. UK: Duckworth.
 
*Jolley, Nicholas, ed., 1995. ''The Cambridge Companion to Leibniz''. Cambridge Uni. Press.
 
*LeClerc, Ivor, ed., 1973. ''The Philosophy of Leibniz and the Modern World''. Vanderbilt Uni. Press.
 
*Loemker, Leroy, 1969a, "Introduction" to his ''Leibniz: Philosophical Papers and Letters''. Reidel: 1-62.
 
*[[Arthur O. Lovejoy]], 1957 (1936). "Plenitude and Sufficient Reason in Leibniz and Spinoza" in his ''The Great Chain of Being''. Harvard Uni. Press: 144-82. Reprinted in Frankfurt, H. G., ed., 1972. ''Leibniz: A Collection of Critical Essays''. Anchor Books.
 
*MacDonald Ross, George, 1999, "Leibniz and Sophie-Charlotte" in Herz, S., Vogtherr, C.M., Windt, F., eds., ''Sophie Charlotte und ihr Schloß''. München: Prestel: 95–105. [http://www.philosophy.leeds.ac.uk/GMR/homepage/sophiec.html English translation.]
 
*Perkins, Franklin, 2004. ''Leibniz and China: A Commerce of Light''. Cambridge Uni. Press.
 
*Riley, Patrick, 1996. ''Leibniz's Universal Jurisprudence: Justice as the Charity of the Wise''. Harvard Uni. Press.
 
 
 
Advanced
 
*Adams, Robert M., 1994. ''Leibniz: Determinist, Theist, Idealist''. Oxford Uni. Press.
 
*[[Louis Couturat]], 1901. ''La Logique de Leibniz''. Paris: Felix Alcan. [http://philosophy2.ucsd.edu/~rutherford/Leibniz/intro.htm Donald Rutherford's English translation in progress.]
 
*Ishiguro, Hide, 1990 (1972). ''Leibniz's Philosophy of Logic and Language''. Cambridge Uni. Press.
 
*Lenzen, Wolfgang, 2004. [http://www.philosophie.uni-osnabrueck.de/Woods.htm "Leibniz's Logic,"] in Gabbay, D., and Woods, J., eds., ''Handbook of the History of Logic, Vol. 3''. North Holland: 1-84.
 
*Mates, Benson, 1986. ''The Philosophy of Leibniz : Metaphysics and Language''. Oxford Uni. Press.
 
*Mercer, Christia, 2001. ''Leibniz's metaphysics : Its Origins and Development''. Cambridge Uni. Press.
 
*[[André Robinet]], 2000. ''Architectonique disjonctive, automates systémiques et idéalité transcendantale dans l'oeuvre de G.W. Leibniz: Nombreux textes inédits ''. [http://www.vrin.fr/html/main.htm Vrin]
 
*Rutherford, Donald, 1998. ''Leibniz and the Rational Order of Nature''. Cambridge Uni. Press.
 
*Wilson, Catherine, 1989. ''Leibniz's Metaphysics''. Princeton Uni. Press.
 
*Woolhouse, R. S., ed., 1993. ''G. W. Leibniz: Critical Assessments'', 4 vols. Routledge. A remarkable and regrettably expensive one-stop collection of many valuable articles.
 
 
 
[http://www.hfac.uh.edu/gbrown/philosophers/leibniz/ Online bibliography,] by Gregory Brown.
 
 
 
==Other works cited==
 
*[[Martin Davis]], 2000. ''The Universal Computer: The Road from Leibniz to [[Turing]]''. W W Norton.
 
*Du Bois-Reymond, Paul, 18nn, "Leibnizian Thoughts in Modern Science," ???.<!--details, please—>
 
*[[Ivor Grattan-Guinness]], 1997. ''The Norton History of the Mathematical Sciences''. W W Norton.
 
*Hirano, Hideaki, 1997, "Cultural Pluralism And Natural Law." Unpublished.
 
*[[Benoit Mandelbrot]], 1977. ''The Fractal Geometry of Nature''. Freeman.
 
*[[Simon Conway Morris]], 2003. ''Life's Solution: Inevitable Humans in a Lonely Universe''. Cambridge Uni. Press.
 
*Ward, P. D., and Brownlee, D., 2000. ''Rare Earth: Why Complex Life is Uncommon in the Universe''. Springer Verlag.
 
*Zalta, E. N., 2000, "[http://mally.stanford.edu/leibniz.pdf A (Leibnizian) Theory of Concepts]," ''Philosophiegeschichte und logische Analyse / Logical Analysis and History of Philosophy 3'': 137-183.
 
 
 
==Quotes== <!--Please move the following to Wikiquote, if not already there—>
 
{{Wikiquote}}
 
[http://en.wikiquote.org/wiki/Gottfried_Leibniz More quotes.] Wiener (1951: 567-70) lists 44 quotable "proverbs" beginning with "Justice is the charity of the wise."
 
*"In the realm of spirit, seek clarity; in the material world, seek utility." Mates's (1986: 15) translation of Leibniz's motto.
 
*"With every lost hour, a part of life perishes." "Deeds make people." Loemker's (1969: 58) translation of other Leibniz mottoes.
 
*"The ''monad''... is nothing but a simple substance which enters into compounds. ''Simple'' means without parts... Monads have no windows through which anything could enter or leave." ''Monadology''  (LL §67.1,7)
 
*"I maintain that men could be incomparably happier than they are, and that they could, in a short time, make great progress in increasing their happiness, if they were willing to set about it as they should. We have in hand excellent means to do in 10 years more than could be done in several centuries without them, if we apply ourselves to making the most of them, and do nothing else except what must be done." (Translated in Riley 1972: 104, and quoted in Mates 1986: 120)
 
 
 
==See also==
 
*[[monadology]]
 
*[[monad]]
 
*[[characteristica universalis]]
 
*[[universal language]]
 
*[[Calculus ratiocinator]]
 
*[[alphabet of human thought]]
 
*[[Newton v. Leibniz calculus controversy]]
 
*[[Leibniz-Gemeinschaft]]
 
*[[Leibniz formula]]
 
*[[digital philosophy]]
 
* [[Anthropic Principle]]
 
*[[Stepped Reckoner]]
 
  
==External links==
+
* [http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Leibniz.html Leibniz, MacTutor Biography]  
*[http://www.earlymoderntexts.com/f_leibniz.html Online texts] in easier-to-read versions.
 
*[http://www.hfac.uh.edu/gbrown/philosophers/leibniz/ Leibnitiana] -- Gregory Brown.
 
* [http://www.videolexikon.com/skriptfachgebiet_Geschichte.htm ''Monadologie'', in German.]
 
* [http://www.leibniz-translations.com/ Lloyd Strickland's web page.] Scroll down for many Leibniz links.
 
*[http://philosophy2.ucsd.edu/~rutherford/Leibniz/leibsoc.htm Table of contents] for the ''Leibniz Review'', 1998-.
 
* [http://www.egs.edu/resources/gottfriedleibniz.html European Graduate School - Gottfried Leibniz.]
 
* {{MacTutor Biography|id=Leibniz}}
 
* [http://www.kirjasto.sci.fi/leibnitz.htm Leibniz biography and bibliography.]
 
* [http://www.harrymaugans.com/2006/03/30/voltaires-candide/ Leibniz] compared to Volaire and Candide
 
* [http://www.utm.edu/research/iep/l/leib-met.htm The Internet Encyclopedia of Philosophy: Leibniz] — Douglas Burnham.
 
 
* Stanford Encyclopedia of Philosophy. Leibniz on:
 
* Stanford Encyclopedia of Philosophy. Leibniz on:
** [http://plato.stanford.edu/entries/leibniz-ethics/ Ethics] — Andrew Youpa.
+
** [http://plato.stanford.edu/entries/leibniz-ethics/ Ethics]  
** [http://plato.stanford.edu/entries/leibniz-causation/ Causation] — Mark Bobro.
+
** [http://plato.stanford.edu/entries/leibniz-causation/ Causation]  
** [http://plato.stanford.edu/entries/leibniz-evil/ Problem of evil] — Michael Murrary.
+
** [http://plato.stanford.edu/entries/leibniz-evil/ Problem of evil]  
** [http://plato.stanford.edu/entries/leibniz-mind/ Philosophy of mind] — Kulstad and Carlin.
+
** [http://plato.stanford.edu/entries/leibniz-mind/ Philosophy of mind]  
*[http://encyclopedia.jrank.org/LAP_LEO/LEIBNITZ_LEIBNIZ_GOTTFRIED_WILH.html Encyclopedia Britannica, 11th ed.]
+
*[http://encyclopedia.jrank.org/LAP_LEO/LEIBNITZ_LEIBNIZ_GOTTFRIED_WILH.html Encyclopedia Britannica], 1911 ed.
* {{gutenberg author| id=Leibniz+Gottfried+Wilhelm+Freiherr+von | name=Gottfried Leibniz}}
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*[http://www.gutenberg.org/browse/authors/l#a7168 Works of Leibniz] at Project Gutenberg
 
 
<!-- interwiki —>
 
 
 
  
[[Category:17th century mathematicians|Leibniz, Gottfried]]
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[[Category:Biography]]
[[Category:18th century mathematicians|Leibniz, Gottfried]]
 
[[Category:18th century philosophers|Leibniz]]
 
[[Category:Christian philosophers|Leibniz, Gottfried]]
 
[[Category:Dynamicists|Leibniz, Gottfried]]
 
[[Category:Early modern philosophers|Leibniz, Gottfried]]
 
[[Category:Enlightenment philosophers|Leibniz]]
 
[[Category:German mathematicians|Leibniz, Gottfried]]
 
[[Category:German philosophers|Leibniz, Gottfried]]
 
[[Category:Idealists|Leibniz, Gottfried]]
 
[[Category:Rationalists|Leibniz, Gottfried]]
 
[[Category:Polymaths|Leibniz, Gottfried]]
 
[[Category:German physicists|Leibniz, Gottfried]]
 
[[Category:Christians in science|Leibniz, Gottfried]]
 
 
[[Category:Philosophy and religion]]
 
[[Category:Philosophy and religion]]
  
 
{{Credit|55839832}}
 
{{Credit|55839832}}

Latest revision as of 16:19, 27 June 2017

Western Philosophers
Seventeenth-century philosophy
(Modern Philosophy)
Gottfried Wilhelm von Leibniz.jpg
Name: Gottfried Wilhelm Leibniz
Birth: July 2, 1646 (Leipzig, Germany)
Death: November 14, 1716 (Hanover, Germany)
School/tradition: Continental rationalism
Main interests
Metaphysics, epistemology, science, mathematics, theodicy
Notable ideas
Calculus, innate knowledge, optimism, monad
Influences Influenced
Plato, Aristotle, Ramon Llull, Scholastic philosophy, Rene Descartes, Christiaan Huygens Many later mathematicians, Christian Wolff, Immanuel Kant, Bertrand Russell, Abraham Robinson

Gottfried Wilhelm Leibniz (also Leibnitz or von Leibniz) (July 1, 1646 - November 14, 1716) was a German polymath, deemed a universal genius in his day and since. Educated in law and philosophy, and serving as factotum to two major German noble houses, Leibniz played a major role in the European politics and diplomacy of his day. His work touched on nearly every subject imaginable, from logic and mathematics to civil engineering and politics. Philosophers today see him as representing one of the peaks of early modern rationalism, with his conviction that reasoning was capable of revealing all truths of the universe.

Leibniz attempted to establish a universal, integral, and unified system of thought that can be applicable to diverse areas in order to unify all partial truths dispersed into different areas. Leibniz strove for the unity of knowledge not by reductionism but by a metaphysical approach within which harmony is established among diverse components. His thoughts contain rich innovative insights that are yet to be studied and explored today.

Life

Leibniz's life was mainly spent working for various German nobles. Though such a career may have kept him from producing the sort of grand treatise characteristic of most great early modern philosophers, it allowed him to travel extensively in Europe, encountering (and influencing) many of the best minds of his day.

Coming of age

Leibniz was born on July 1, 1646, the child of Friedrich Leibnütz and Catherina Schmuck. He began spelling his name "Leibniz" early in adult life, but others often referred to him as "Leibnitz," a spelling which persisted until the twentieth century.

When Leibniz was six years old, his father, a Professor of Moral Philosophy at the University of Leipzig, died, leaving a personal library to which Leibniz was granted free access from age seven onwards. By age 12, he had taught himself Latin, a language he employed freely all his life, and had begun to study Greek. He entered his father's university at 14, and completed his university studies by age 20, specializing in law and mastering the standard university course of classics, logic, and scholastic philosophy. However, his education in mathematics was not up to the French and British standard of the day. In 1666 he completed his habilitation thesis (which would allow him to teach), On the Art of Combinations. When Leipzig declined to assure him a position teaching law upon graduation, Leibniz submitted to the University of Altdorf near Nuremberg the thesis he had intended to submit at Leipzig, and obtained his doctorate in law in five months. He then declined an offer of academic appointment at Altdorf, and spent the rest of his life in the service of two major German noble families.

Career

Leibniz's first position was as a salaried alchemist in Nuremberg, an area he remained interested in for the rest of his life. He soon met J. C. von Boineburg, a diplomat of the Bishop Elector of Mainz, Johann Philipp von Schönborn. Von Boineburg hired Leibniz as an assistant, and shortly thereafter introduced Leibniz to the elector. Von Schönborn soon hired Leibniz as well as a legal and political adviser.

Von Boineburg did much to promote Leibniz's reputation, and the latter's memoranda and letters began to attract favorable notice. Leibniz's service to the Elector soon took on a diplomatic role. The main European geopolitical reality during Leibniz's adult life was the ambition of the French king, Louis XIV, backed by French military and economic might. This was especially worrisome for the German states, who had been left exhausted, fragmented, and economically backward by the Thirty Years' War. Leibniz helped von Boineburg devise a plan to protect German-speaking Europe by distracting Louis. France would be invited to take Egypt as a stepping-stone towards an eventual conquest of the Dutch East Indies. Having directed it's military might at Egypt, France would have too few resources to attack Germany. This plan obtained the Elector's cautious support. In 1672, Leibniz was sent to Paris to present the idea to the French, but the plan was soon overtaken by events and became moot. Napoleon's failed invasion of Egypt in 1798 can perhaps be seen as an unwitting implementation of Leibniz's plan.

Thus Leibniz began several years in Paris, during which he greatly expanded his knowledge of mathematics and physics, and began contributing to both. He met Nicolas Malebranche and Antoine Arnauld, the leading French philosophers of the day, and studied the writings of Rene Descartes and Blaise Pascal, unpublished as well as published. He befriended a German mathematician, Ehrenfried Walther von Tschirnhaus; they corresponded for the rest of their lives. Especially fateful was Leibniz's making the acquaintance of the Dutch physicist and mathematician Christiaan Huygens, then active in Paris. Soon after arriving in Paris, Leibniz received a rude awakening; his knowledge of mathematics and physics was spotty. With Huygens as mentor, he began a program of self-study that soon resulted in his making major contributions to both subjects, including inventing his version of the differential and integral calculus.

In 1673 Leibniz made a brief trip to London. There he made the acquaintance of Henry Oldenburg. Oldenburg was then the secretary of the Royal Society, who was particularly impressed by a calculating machine Leibniz had invented—one that could perform all four arithmetical operations. That same year, Leibniz was elected a fellow of the Society.

When Leibniz returned to Paris, however, he found himself unemployed (both von Boineburg and von Schönborn had died by 1673). He had hoped for employment by the Paris Academy, but soon realized that it would not be forthcoming (he was finally accepted in 1700). He therefore somewhat reluctantly accepted a post as councilor at the court of Hanover for Duke Johann Friedrich of Brunswick-Lüneburg.

Leibniz managed to delay his arrival in Hanover until the end of 1676, after making another short journey to London. On the journey from London to Hanover, Leibniz stopped in The Hague where he met Anton van Leeuwenhoek, the discoverer of microorganisms. He also spent several days in intense discussion with Baruch Spinoza, who had just completed his masterwork, the Ethics. Leibniz respected Spinoza's powerful intellect, but was dismayed by his conclusions that contradicted Christian orthodoxy, and found many of his proofs unsound.

In the service of the House of Brunswick (also: Braunschweig), Leibniz was engaged in a wide variety of projects. He attempted a number of complicated mechanical schemes for draining a series of mines in the Harz Mountains (none of which appeared to have been successful). He was assigned the massive task of compiling a history of the Guelph lineage (of which the House of Brunswick was a part), as a means towards furthering the family's aspirations. The Duke also enlisted Leibniz's legal and philosophical expertise in attempting to reunite the Protestant churches with the Catholic Church. Finally, Leibniz began producing the first mature expressions of his philosophy (beginning with the Meditations on Knowledge, Truth and Ideas of 1684).

The rest of Leibniz's life was occupied with various tasks associated with Hanover. He never produced the requested history of family, but nevertheless examined numerous archives and compiled much preparatory material. He traveled constantly to various courts throughout Europe, and was able to establish an Academy of Sciences in Berlin while initiating the formation of similar societies in Vienna and St. Petersburg. Despite a large number of municipal and legal projects, he maintained an extensive correspondence on nearly every topic imaginable (around 15,000 of his letters survive). It is therefore not surprising that his relations with his employers became somewhat strained, and when Duke Georg Ludwig was crowned George I of England, the family moved while leaving Leibniz in Hanover.

The last years of Leibniz's life were not happy ones. Abandoned by the House of Hanover, he made some final attempts at completing the family history and compiling an authoritative expression of his philosophy. Neither attempt was successful. He died in November of 1716.

The Calculus Dispute

Leibniz is credited, along with Isaac Newton, with inventing the infinitesimal calculus. According to Leibniz's notebooks, a critical breakthrough occurred on November 11, 1675, when he employed integral calculus for the first time to find the area under the function y = x. He introduced several notations used to this day, for instance the integral sign ∫ representing an elongated S, from the Latin word summa and the d used for differentials, from the Latin word differentia. Leibniz did not publish any of his results until 1684 (two years prior to Newton's Principia). The product rule of differential calculus is still called "Leibniz's rule."

Leibniz's approach to the calculus fell well short of later standards of rigor (the same can be said of Newton's). We now see a Leibniz "proof" as being in truth mostly a heuristic hodgepodge, mainly grounded in geometric intuition and an intuitive understanding of differentials. Leibniz also freely invoked mathematical entities he called infinitesimals, manipulating them freely in ways suggesting that they had paradoxical algebraic properties. George Berkeley, in a tract called The Analyst and elsewhere, ridiculed this and other aspects of the early calculus, pointing out that natural science grounded in the calculus required just as big of a leap of faith as theology grounded in Christian revelation.

Modern calculus emerged in the nineteenth century, and banished infinitesimals into the wilderness of obsolete mathematics (although engineers, physicists, and economists continued to use them). But beginning in 1960, Abraham Robinson showed how to make sense of Leibniz's infinitesimals, and how to give them algebraic properties free of paradox. The resulting nonstandard analysis can be seen as a great belated triumph of Leibniz's mathematical and ontological intuition.

From 1711 until his death, Leibniz's life was envenomed by a long dispute with John Keill, Newton, and others, over whether Leibniz had invented the calculus independently of Newton, or whether he had merely invented another notation for ideas that were fundamentally Newton's. Today, the predominant view is that Newton developed his calculus first, then mentioned to Leibniz several things that his new method could accomplish (without specifying anything about the method itself). Leibniz took this cue to develop his own calculus, which he published quickly, perhaps with less-than-admirable motives.

Writings

Leibniz wrote in three languages: scholastic Latin, French, and (least often) German. During his lifetime, he published many pamphlets and scholarly articles, but relatively little philosophy. Only one substantial book appeared posthumously, his Nouveaux essais sur l'entendement humain (a response to John Locke's Essay Concerning Human Understanding. Only in 1895, when Bodemann completed his catalogs of Leibniz's manuscripts and correspondence, did the enormous extent of Leibniz's Nachlass become clear: about 15,000 letters to more than one thousand recipients plus more than 40,000 other items. Moreover, quite a few of these letters are of essay length. Much of his vast correspondence, especially the letters dated after 1685, remains unpublished, and much of what is published has been so only in recent decades. The amount, variety, and disorder of Leibniz's writings are a predictable result of a situation he described as follows:

I cannot tell you how extraordinarily distracted and spread out I am. I am trying to find various things in the archives; I look at old papers and hunt up unpublished documents. From these I hope to shed some light on the history of the [House of] Brunswick. I receive and answer a huge number of letters. At the same time, I have so many mathematical results, philosophical thoughts, and other literary innovations that should not be allowed to vanish that I often do not know where to begin. (1695 letter to Vincent Placcius in Gerhardt, Philosophical Writings of Leibniz III: 194. Revision of translation in Mates 1986.)

The extant parts of the critical edition of Leibniz's writings are organized as follows:

  • Series 1. Political, Historical, and General Correspondence. 21 vols., 1666-1701.
  • Series 2. Philosophical Correspondence. 1 vol., 1663-85.
  • Series 3. Mathematical, Scientific, and Technical Correspondence. 6 vols., 1672-96.
  • Series 4. Political Writings. 6 vols., 1667-98.
  • Series 5. Historical and Linguistic Writings. Inactive.
  • Series 6. Philosophical Writings. 7 vols., 1663-90, and Nouveaux essais sur l'entendement humain.
  • Series 7. Mathematical Writings. 3 vols., 1672-76.
  • Series 8. Scientific, Medical, and Technical Writings. In preparation.

Some of these volumes, along with work in progress, are available online, for free. Even though work on this edition began in 1901, only 22 volumes had appeared by 1990, in part because the only additions between 1931 and 1962 were four volumes in Series 1.

Posthumous reputation

When Leibniz died, his reputation was in decline. Many thought of him primarily as the author of Théodicée, whose supposed central argument Voltaire was to lampoon in his Candide. Leibniz had an ardent disciple, Christian Wolff, who briefly generated much enthusiasm for 'Leibnizian-Wolffian' philosophy, only to become a principal target of Kant. Much of Europe came to doubt that Leibniz had invented the calculus independently of Newton, and much of his whole work in mathematics and physics was neglected. His work on law, diplomacy, and history was seen as of ephemeral interest. The vastness and richness of his correspondence went unsuspected.

Leibniz's long march to his present glory began with the 1765 publication of the Nouveaux Essais, which Kant read closely. In 1768 Dutens edited the first multi-volume edition of Leibniz's writings, followed in the nineteenth century by a number of editions, including those edited by Erdmann, Foucher de Careil, Gerhardt, Gerland, Klopp, and Mollat. Publication of Leibniz's correspondence with notables such as Antoine Arnauld, Sophia of Hanover, and her daughter Sophia Charlotte of Hanover, began.

In 1900, Bertrand Russell published a study of Leibniz's metaphysics. Shortly thereafter, Louis Couturat published an important study of Leibniz, and edited a volume of Leibniz's heretofore-unpublished writings, mainly on logic. While their conclusions have been debated, they made Leibniz respectable among twentieth-century analytical and linguistic philosophers. With analytic philosophy's renewed interest in metaphysics in the 1960s and 1970s, Leibniz's work has received more and more attention.

Philosopher

There are at least three challenges in developing a plausible summary of Leibniz's philosophy. First, unlike nearly every other figure in early modern philosophy, Leibniz left no single philosophical work that can be taken as the definite expression of his main thought. Second, Leibniz's views appear differently in different places, not only because of the development of his thought, but also because he often tailored his writings to his audience. Finally, there is the fact of the vastness of the Leibnizian corpus, which is, for all intents and purposes, simply too large for any one person to adequately survey.

Despite these challenges, certain themes are particularly noteworthy, both because they recur in what seem to be Leibniz's main philosophical works, and because of their distinctive influence on later philosophers.

Unlike Descartes and Spinoza, Leibniz had a thorough university education in ancient and scholastic philosophy, one which he took seriously. His writings show his desire to find some element of truth in each of the various positions. Whereas the Cartesians were eager to abandon the Aristotelian notion of forms, Leibniz attempted to integrate talk of forms into a metaphysics derived from that of Descartes.

Logic

Leibniz is probably the most important logician between Aristotle and 1847, when George Boole and Augustus De Morgan each published books that began modern formal logic. Leibniz enunciated the principal properties of what we now call conjunction, disjunction, negation, identity, set, inclusion, and the empty set. He also provided some groundwork for what would become epistemic and modal logic. Yet Leibniz's vision of logic was far grander than that of any modern logician; perhaps grander than that of any other figure in the history of philosophy.

Leibniz had a remarkable faith that a great deal of human reasoning could be reduced to calculations of a sort, and that such calculations could resolve many differences of opinion:

The only way to rectify our reasonings is to make them as tangible as those of the Mathematicians, so that we can find our error at a glance, and when there are disputes among persons, we can simply say: Let us calculate [calculemus], without further ado, to see who is right. (The Art of Discovery 1685, W 51)

He proposed the creation of a characteristic universalis or "universal characteristic," built on an alphabet of human thought in which each fundamental concept would be represented by a unique "real" character.

It is obvious that if we could find characters or signs suited for expressing all our thoughts as clearly and as exactly as arithmetic expresses numbers or geometry expresses lines, we could do in all matters insofar as they are subject to reasoning all that we can do in arithmetic and geometry. For all investigations which depend on reasoning would be carried out by transposing these characters and by a species of calculus. (Preface to the General Science, 1677. Revision of Rutherford's translation in Jolley 1995, 234. Also W I.4)

More complex thoughts would be represented by combining in some way the characters for simpler thoughts. Leibniz saw that the uniqueness of prime factorization suggests a central role for prime numbers in the universal characteristic.

An example of what Leibniz envisioned is as follows: say that the concept 'man' is composed of the more simple concepts 'rational' and 'animal.' Say that to each of the latter a prime number is assigned: 3 and 5. By multiplying these together, we get a number for 'man': 15. If one later wanted to know whether men were animals, all one would have to do is to find whether the number for the later was a factor of the former. Leibniz envisioned such a means of evaluating the truth of propositions as extending to much more contentious propositions, and thus as a promising means for resolving disputes. Of course, matters would become much more complex with more complex concepts, and one can see Leibniz's interests in establishing academies and developing calculating machines as aimed in this direction.

Much of Leibniz's philosophy makes use of two logical-metaphysical principles whose names he coined. Though these principles are present in earlier philosophers, Leibniz makes the most explicit use of them of anyone up to his time.

  • Identity of indiscernibles: Two things are identical if and only if they share the same properties.
  • Principle of Sufficient Reason: There must be a sufficient reason, often known only to God, for anything to exist, for any event to occur, for any truth to obtain.

Both of these principles correspond closely to aspects of Leibniz's metaphysics.

The Monads

Leibniz's best known contribution to metaphysics is his theory of monads, as exposited in his Monadology. Roughly speaking, monads are to the mental realm what atoms were seen as being to the physical. While making use of the analogy with atoms, however, Leibniz argued that matter was infinitely divisible, and so denied that physical atoms exist (Leibniz in fact sometimes argued first that there must be monads, and then established that such monads could not be extended). Monads, along with God, are the ultimate elements of the universe. The monads are "substantial forms of being" with the following properties: they are eternal, indecomposable, individual, active, subject to their own laws, causally independent of one another, and each reflecting the entire universe in a pre-established harmony.

The ontological essence of a monad is its irreducible simplicity. Unlike extended substances as conceived by Descartes, monads possess no material or spatial character. They also differ from Cartesian extended substance by their complete mutual independence, so that interactions among monads are only apparent. Instead, by virtue of the principle of pre-established harmony (see below), every modification of any monad in the universe was matched by some corresponding modification in every other monad in the universe. Each monad can then be said to 'mirror' the entire universe.

Pre-Established Harmony

Leibniz believed that each monad was metaphysically independent of everything else in the universe, save God. This independence is both ontological and causal. As long as God continues to preserve it, any particular monad could continue to exist while all others are destroyed. Further, no monad is capable of causally affecting another monad, or being affected.

Such a view raises an obvious question: if (as Leibniz held) my mind and body are both monads, why is it that they appear to affect each other. For instance, when I choose to raise my arm, my arm lifts, and when I jam my toe, I experience a certain sensation. Descartes had explained such correlations in terms of genuine causal interaction (via the pineal gland). Many of Descartes' successors found such interaction unintelligible, though, and by Leibniz's time the main alternative was the occasionalist view most prominently advanced by Malebranche. Occasionalism held that, in all such cases, the causal force came directly from God.

Leibniz, however, claimed that occasionalism made causation unacceptably mysterious, with the universe filled with 'miracles.' He saw the Principle of Sufficient Reason as requiring that every change a substance undergoes be explicable in terms of that substance's own essence. On this basis, he formulated an alternative he dubbed 'pre-established harmony.' This view held that, at creation, each substance was essentially programmed by God to undergo all the changes it would ever go. Throughout its existence, then, its changes were merely the result of the unfolding of its nature. In virtue of this, all substances are coordinated in their changes, such that it appears to them that interaction is occurring.

Theodicy and Optimism

The Théodicée tries to justify the apparent imperfections of the world by claiming that it is optimal among all possible worlds. It must be the best possible and most balanced world, because it was created by a perfect God, who is omnipotent and omnibenevolent. It is on this basis that Leibniz believed all monads were coordinated, despite their causal independence. Moreover, many facts about the world could only be known via considering the Principle of Sufficient Reason in combination with knowledge that this world is the best possible.

The statement that "we live in the best of all possible worlds" drew scorn, most notably from Voltaire, who lampooned it in his comic novel Candide by having the character Dr. Pangloss (a parody of Leibniz) repeat it like a mantra. Thus the adjective "panglossian," describing one so naive as to believe that the world about us is the best possible one.

References
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Works by Leibniz

AG = Ariew & Garber 1989. LL = Loemker 1969. W = Wiener 1951. WF = Woolhouse and Francks 1998.

The ongoing critical edition of all of Leibniz's writings is Sämtliche Schriften und Briefe.

The year shown is usually the year in which the work was completed, not of its eventual publication.

  • 1666. De Arte Combinatoria (On the Art of Combination). Partially translated in LL §1 and Parkinson 1966.
  • 1671. Hypothesis Physica Nova (New Physical Hypothesis). LL §8.I (part)
  • 1684. Nova methodus pro maximis et minimis (New Method for maximums and minimums). Translation in Struik, D. J., 1969. A Source Book in Mathematics, 1200-1800. Harvard University Press: 271-81.
  • 1686. Discours de métaphysique]]. Martin and Brown (1988). Jonathan Bennett's translation. AG 35, LL §35, W III.3, WF 1.
  • 1705. Explication de l'Arithmétique Binaire (Explanation of Binary Arithmetic). Gerhardt, Mathematical Writings VII.223.
  • 1710. Théodicée. Farrer, A.M., and Huggard, E.M., trans., 1985 (1952). Theodicy. Open Court. W III.11 (part).
  • 1714. Monadology. Nicholas Rescher, trans., 1991. The Monadology: An Edition for Students. University of Pittsburgh Press. Jonathan Bennett's translation. Latta's translation. AG 213, LL §67, W III.13, WF 19.
  • 1765. Nouveaux essais sur l'entendement humain. Completed 1704. Remnant, Peter, and Bennett, Jonathan, trans., 1996. New Essays on Human Understanding. Cambridge University Press. W III.6 (part). Jonathan Bennett's translation.

Collections of shorter works in translation:

  • Ariew, R., and D. Garber. 1989. Leibniz: Philosophical Essays. Hackett Publishing Company. Paperback edition. ISBN 0872200620
  • Bennett, Jonathan. Various texts.
  • Cook, Daniel J. and Henry Rosemont, Jr. 1994. Leibniz: Writings on China. Open Court. ISBN 0812692500
  • Dascal, Marcelo. 1987. Leibniz: Language, Signs and Thought. John Benjamins. ISBN 9027232806
  • Loemker, Leroy E. 1956. Leibniz: Philosophical Papers and Letters. Second edition, 1975. Springer. ISBN 902770693X
  • Martin, R.N.D., and Stuart Brown. 1988. Discourse on Metaphysics and Related Writings. Reprint edition, 1990. Manchester University Press. ISBN 0719017025
  • Parkinson, G.H.R., 1966. Leibniz: Logical Papers. New York: Oxford University Press. ISBN 0198243065
  • Parkinson, G.H.R. and Mary Morris. 1973. 'Leibniz: Philosophical Writings. Reprint edition, 1991. London: J M Dent & Sons. ISBN 0460870459
  • Riley, Patrick. 1972. Leibniz: Political Writings. Second edition, 1988. Cambridge University Press. ISBN 052135899X
  • Rutherford, Donald. Various texts.
  • Strickland, Lloyd (trans.). 2006. Shorter Leibniz Texts. Continuum Books. ISBN 0826489516. Online.
  • Wiener, Philip. 1951. Leibniz: Selections. Scribner.
    • Regrettably, out of print and lacks index.
  • Woolhouse, R.S., and R. Francks. 1998. Leibniz: Philosophical Texts. New York: Oxford University Press. ISBN 0198751532

Donald Rutherford's online bibliography.

Secondary literature

Introductory

Intermediate

  • Aiton, Eric J. 1985. Leibniz: A Biography. Taylor and Francis. ISBN 0852744706
  • Hall, A. R. 1980. Philosophers at War: The Quarrel between Newton and Leibniz. New edition, 2002. Cambridge University Press. ISBN 052152489X
  • Hostler, J. 1975. Leibniz's Moral Philosophy. UK: Duckworth. US: Barnes and Noble. ISBN 0064929930
  • Jolley, Nicholas (ed.). 1995. The Cambridge Companion to Leibniz. Cambridge University Press. ISBN 0521367697
  • LeClerc, Ivor (ed.). 1973. The Philosophy of Leibniz and the Modern World. Vanderbilt University Press. ISBN 0826511813
  • Loemker, Leroy. 1969a. "Introduction" to his Leibniz: Philosophical Papers and Letters. Reidel: 1-62.
  • Lovejoy, Arthur O. 1957 (1936). "Plenitude and Sufficient Reason in Leibniz and Spinoza" in his The Great Chain of Being. Harvard University Press: 144-82. Reprinted in H. G. Frankfurt (ed.), 1972. Leibniz: A Collection of Critical Essays. Doubleday. ISBN 0385033087
  • MacDonald Ross, George. 1999. "Leibniz and Sophie-Charlotte" in S. Herz, C. M. Vogtherr, and F. Windt (eds.), Sophie Charlotte und ihr Schloß. München: Prestel: 95–105. English translation.
  • Perkins, Franklin. 2004. Leibniz and China: A Commerce of Light. Cambridge University Press. ISBN 0521830249
  • Riley, Patrick. 1996. Leibniz's Universal Jurisprudence: Justice as the Charity of the Wise. Harvard University Press. ISBN 0674524071

Advanced

  • Adams, Robert M. 1994. Leibniz: Determinist, Theist, Idealist. Reprint edition, 1998. Oxford University Press. ISBN 0195126491
  • Couturat, Louis. 1901. La Logique de Leibniz. Paris: Felix Alcan. Donald Rutherford's English translation in progress.
  • Ishiguro, Hide. 1972. Leibniz's Philosophy of Logic and Language. Second edition, 1991. Cambridge University Press. ISBN 0521377811
  • Lenzen, Wolfgang. 2004. "Leibniz's Logic," in D. Gabbay and J. Woods (eds.), Handbook of the History of Logic, Vol. 3. North Holland: 1-84.
  • Mates, Benson. 1986. The Philosophy of Leibniz: Metaphysics and Language. Reprint edition, 1989. Oxford University Press. ISBN 0195059468
  • Mercer, Christia. 2001. Leibniz's metaphysics: Its Origins and Development. Paperback edition, 2006. Cambridge University Press. ISBN 0521029929
  • Robinet, André. 2000. Architectonique disjonctive, automates systémiques et idéalité transcendantale dans l'oeuvre de G.W. Leibniz: Nombreux textes inédits. Vrin
  • Rutherford, Donald. 1995. Leibniz and the Rational Order of Nature. New paperback edition, 1998. Cambridge University Press. ISBN 0521597374
  • Wilson, Catherine. 1989. Leibniz's Metaphysics. Princeton University Press. ISBN 0691073597
  • Woolhouse, R. S. (ed.). 1993. G. W. Leibniz: Critical Assessments, 4 vols. Routledge. ISBN 041503809X
    • A remarkable and regrettably expensive one-stop collection of many valuable articles.

External links

All links retrieved June 27, 2017.

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