Editing Gottfried Wilhelm Leibniz (section)

===1666–1676<!--linked from the lead section-->===
[[File:Gottfried Wilhelm Leibniz c1700.jpg|thumb|Gottfried Wilhelm Leibniz]]
Leibniz's first position was as a salaried secretary to an [[alchemy|alchemical]] society in [[Nuremberg]].<ref>Ariew R., G.W. Leibniz, life and works, p. 21 in ''The Cambridge Companion to Leibniz'', ed. by N. Jolley, Cambridge University Press, 1994, {{isbn|0-521-36588-0}}. [https://books.google.com/books?id=SnRis5Gdi8gC&pg=PA21 Extract of page 21]</ref> He knew fairly little about the subject at that time but presented himself as deeply learned. He soon met [[Johann Christian von Boyneburg]] (1622–1672), the dismissed chief minister of the [[Prince-elector|Elector]] of [[Mainz]], [[Johann Philipp von Schönborn]].<ref>Mackie (1845), 43</ref> Von Boyneburg 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 the Electorate.<ref>Mackie (1845), 44–45</ref> In 1669, Leibniz was appointed assessor in the Court of Appeal. Although von Boyneburg died late in 1672, Leibniz remained under the employment of his widow until she dismissed him in 1674.<ref>{{cite book |last1=Benaroya |first1=Haym |last2=Han |first2=Seon Mi |last3=Nagurka |first3=Mark |title=Probabilistic Models for Dynamical Systems |date=2 May 2013 |publisher=CRC Press |isbn=978-1-4398-5015-2 |url=https://books.google.com/books?id=rYEqBgAAQBAJ&pg=PA135 |language=en}}</ref>

Von Boyneburg did much to promote Leibniz's reputation, and the latter's memoranda and letters began to attract favorable notice. After Leibniz's service to the Elector there soon followed a diplomatic role. He published an essay, under the pseudonym of a fictitious Polish nobleman, arguing (unsuccessfully) for the German candidate for the Polish crown. The main force in European geopolitics during Leibniz's adult life was the ambition of [[Louis XIV of France]], backed by French military and economic might. Meanwhile, the [[Thirty Years' War]] had left [[German language in Europe|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,<ref>Mackie (1845), 58–61</ref> but the plan was soon overtaken by the outbreak of the [[Franco-Dutch War]] and became irrelevant. Napoleon's [[French campaign in Egypt and Syria|failed invasion of Egypt in 1798]] can be seen as an unwitting, late implementation of Leibniz's plan, after the Eastern hemisphere colonial supremacy in Europe had already passed from the Dutch to the British.

Thus Leibniz went to Paris in 1672. Soon after arriving, he met Dutch physicist and mathematician [[Christiaan Huygens]] and realised that his own knowledge of mathematics and physics was patchy. With Huygens as his mentor, he began a program of [[self-study]] that soon pushed him to making major contributions to both subjects, including discovering his version of the differential and integral [[calculus]]. He met [[Nicolas 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.<ref>{{Cite SEP|url-id=leibniz|title=Gottfried Wilhelm Leibniz|date=July 24, 2013|edition=Spring 2020|last=Look|first=Brandon C.}}</ref> He befriended a German mathematician, [[Ehrenfried Walther von Tschirnhaus]]; they corresponded for the rest of their lives.{{citation needed|date=December 2024}}

[[File:Leibnitzrechenmaschine.jpg|thumb|[[Stepped reckoner]]]]

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 English government in London, early in 1673.<ref>Mackie (1845), 69–70</ref> There Leibniz came into acquaintance of [[Henry Oldenburg]] and [[John Collins (mathematician)|John Collins]]. He met with the [[Royal Society]] where he demonstrated a calculating machine that he had designed and had been building since 1670. The machine was able to execute all four basic operations (adding, subtracting, multiplying, and dividing), and the society quickly made him an external member.{{citation needed|date=December 2024}}

The mission ended abruptly when news of the Elector's death (12 February 1673) reached them. Leibniz promptly returned to Paris and not, as had been planned, to Mainz.<ref>Mackie (1845), 73–74</ref> The sudden deaths of his two patrons in the same winter meant that Leibniz had to find a new basis for his career.{{citation needed|date=December 2024}}

In this regard, a 1669 invitation from Duke [[John Frederick, Duke of Brunswick-Lüneburg|John Frederick]] of [[Brunswick-Lüneburg|Brunswick]] to visit Hanover proved to have been fateful. Leibniz had declined the invitation, but had begun corresponding with the duke in 1671. In 1673, the duke offered Leibniz the post of counsellor. Leibniz very reluctantly accepted the position two years later, only after it became clear that no employment was forthcoming in Paris, whose intellectual stimulation he relished, or with the [[Habsburg]] imperial court.<ref name="CRC Press">{{cite book|last1=Davis|first1=Martin|title=The Universal Computer : The Road from Leibniz to Turing|year=2018|publisher=CRC Press|isbn=978-1-138-50208-6|pages=9}}</ref>

In 1675 he tried to get admitted to the [[French Academy of Sciences]] as a foreign honorary member, but it was considered that there were already enough foreigners there and so no invitation came. He left Paris in October 1676.