Editing Leonhard Euler (section)

==Personal philosophy and religious beliefs==
Euler was religious throughout his life.<ref name="zum werk leonhard" /> Much of what is known of his religious beliefs can be deduced from his ''[[Letters to a German Princess]]'' and an earlier work, ''Rettung der Göttlichen Offenbahrung gegen die Einwürfe der Freygeister'' (''Defense of the Divine Revelation against the Objections of the Freethinkers''). These show that Euler was a devout Christian who believed the Bible to be inspired; the ''Rettung'' was primarily an argument for the [[Biblical inspiration|divine inspiration of scripture]].<ref name="theology"/><ref name="Ho2" />

Euler opposed the concepts of [[Gottfried Leibniz|Leibniz's]] [[monadism]] and the philosophy of [[Christian Wolff (philosopher)|Christian Wolff]].{{sfn|Calinger|1996|p=123}} He insisted that knowledge is founded in part on the basis of precise quantitative laws, something that monadism and Wolffian science were unable to provide. Euler called Wolff's ideas "heathen and atheistic".<ref name="wolff"/>

There is a legend<ref name="diderot"/> inspired by Euler's arguments with secular philosophers over religion, which is set during Euler's second stint at the St. Petersburg Academy. The French philosopher [[Denis Diderot]] was visiting Russia on Catherine the Great's invitation. The Empress was alarmed that Diderot's arguments for atheism were influencing members of her court, and so Euler was asked to confront him. Diderot was informed that a learned mathematician had produced a proof of the [[existence of God]]: he agreed to view the proof as it was presented in court. Euler appeared, advanced toward Diderot, and in a tone of perfect conviction announced this [[Non sequitur (literary device)|non sequitur]]:

"Sir, <math>\frac{a+b^n}{n}=x</math>, hence God exists –reply!"

Diderot, to whom (says the story) all mathematics was gibberish, stood dumbstruck as peals of laughter erupted from the court. Embarrassed, he asked to leave Russia, a request Catherine granted. However amusing the anecdote may be, it is [[wikt:apocryphal|apocryphal]], given that Diderot himself did research in mathematics.<ref name=persee/>
The legend was apparently first told by [[Dieudonné Thiébault]] with embellishment by [[Augustus De Morgan]].<ref name="diderot"/>