By Steve Bishop

*(Disclaimer: The views expressed by guest authors do not necessarily reflect those of GodandMath.com. Guest articles are sought after for the purpose of bringing more diverse viewpoints to the topics of mathematics and theology. The point is to foster discussion. To this end respectful and constructive comments are highly encouraged.)*

### Leonhard Euler (1707-1783)

Euler was a committed Christian and, apparently, a biblical literalist as well as being (arguably) one of the greatest mathematicians ever – he was certainly the most prolific (apart from perhaps Paul Erdos).

According to one website (condensed from E T Bell’s *Men of Mathematics*):

Euler remained a Christian all of his life and often read to his family from the Bible. One story about his religion during his stay in Russia involved the atheistic philosopher Diderot. Diderot had been invited to the court by Catherine the Great, but then annoyed her by trying to convert everyone to atheism. Catherine asked Euler for help, and he informed Diderot, who was ignorant of mathematics, that he would present in court an algebraic proof of the existence of God, if Diderot wanted to hear it. Diderot was interested, and, according to De Morgan, Euler advanced toward Diderot, and said gravely, and in a tone of perfect conviction: “Sir, (a + bn) / n = x , hence God exists; reply! ” Diderot had no reply, and the court broke into laughter. Diderot immediately returned to France.

Leonhard was born into a Calvinist family and his father, Paul, was a minister in the church as was his grandfather. Euler’s father wanted him to follow him into the church. However, being a good Calvinist he realised that one could serve God through mathematics as well as theology and seeing his son’s ability in and passion for mathematics allowing him to pursue mathematics.

Euler always held an interest in theology as well as mathematics. For him mathematics gave insight into God’s good creation.

Eulogy of Euler by Nicolas Fuss:

He was entirely imbued with respect for religion and his piety was sincere and his devotion was full of fervor. He fulfilled with the greatest detail all the duties of a Christian. He loved everyone, and if he felt stirrings of indignations it was against those enemies of religion, especially against the declared apostles of atheism that he made a stand in the defense of the Revelation against the objections of atheists in a work which was published in Berlin in 1747.

Dan Graves in his *Scientists of Faith* has this to say of Euler:

Euler retained his firm Calvinist beliefs throughout life, holding daily prayer and worship in his home and sometimes preaching.

Euler was one of the first inventors of the number game Suduko. Though he called it Latin squares.

He introduced the letter *e* to represent the base of natural logs, *f*(*x*) to denote functions,and made countless contributions to number theory and graph theory, most notably he showed that the Koinisberg bridge problem was unsolvable.

His name is associated with angles, approximation, circles, cycle, criterion, graphs, operator’s, polynomials, pseudo primes, … and Euler’s identity: said to be the most beautiful formula in the world.

And let’s not forget:

**V – E + F = 2**

Euler was able to serve his God through his mathematics.

Also on Euler:

- The Euler archive
- The works of Euler online
- a paper by Duncan Roper on Euler and the Koinisberg bridges problem
- a brief bio
- Rouse Ball’s bio of Euler
- The Euler archive blog

*Steve Bishop is the compiler of *A Bibliography for a Christian Approach to Mathematics *and the author of several articles on the relationship between faith and math. Look for future posts from him in this series on Christian Mathematicians.*