Just One Thing: Leonhard Euler

Somewhere in your education you were, I suspect, introduced to the symbol π. This represents the ratio of a circle’s circumference to its diameter, an irrational constant for all circles often approximated as 3.14. The notation was first used by William Jones in 1706, but Leonhard Euler make it stick. Those of you with deeper math education know that ƒ(x) designates the value of a function, and i is used to designate the square root of -1. Credit these to Euler, as well. I could fill a volume, for Euler was arguably the most brilliant and certainly the most productive mathematician in modern times. During his lifetime Euler published around 800 works. After he died, he continued to publish for decades. (Somehow that feels like cheating but yes, dozens of papers of his were published after he died.) Euler (pronounced oy-ler) was so prolific that historians credit him with “one third of all publications in the fields of mathematics, theoretical physics, and engineering mechanics between the years 1725 and 1800.” This was no mean feat. The eighteenth century included the several junior Bernoulli, Fourier, Lagrange, Laplace, Gauss, and dozens more – part of a golden age for math. And Euler, wrote mathematician Pierre-Simon Laplace, “is the master of us all.” Euler wrote on all manner of subjects: number theory, graph theory, optics, the shape of the not-quite-spherical earth (a hot topic back then), ship design and navigation, medicine, chemistry, music theory, the theory of tides, elasticity, ballistics, compressible and incompressible fluids, and on and on including Letters to a German Princess, which was translated into eight languages and became an international bestseller, one of the most popular science books ever written.    

Somewhere in your education you were, I suspect, introduced to the conviction that science and religion are incompatible, that scientific thinking is an alternative to religious thinking, and better. The idea has become common in film, television, social media, and university education, but it began as part of the anti-Christian diatribe of Euler’s enlightened generation. As an idea, though, it is just flat wrong. In fact, nearly all early modern scientists were Christians, most of the rest were Jews, and all owed a debt of allegiance to Muslim scientists who came before them. This of course makes sense: Christians believe in an ordered, knowable creation that is here for us to live in, work with, and steward. Creation is the means through which grace comes and it is through the created order that we love God and neighbor. With due regard for ancient Greeks and Indians, it was the line of Abraham that created modern science, with Christians making the dominant contributions.   

Portrait of Leonhard Euler, by Jakob Emanuel Handmann (1753). Kunstmuseum Basel. 

Euler knew this. He lived it. Euler was a devout, sometimes outspoken Christian whose mathematical and scientific genius was an expression of his devotion to Christ. Born near Basel, Switzerland, in 1707, the son and grandson of pastors, Euler’s father intended for him to pursue ministry as well. Math grabbed hold of his capacious imagination, though, and his tutor, the renowned Johann Bernoulli, gave him the best possible education. As a professor in St Petersburg and Berlin, he wrote on a vast range of theoretical and practical problems. During his lifetime, freethinking and rationalist opposition to Christianity intensified in the centers of learning and power, ranging from quiet skepticism to outright hatred. (One famous, brutal cry of the Enlightenment rationalists: that the last king be strangled with the entrails of the last priest. Neither rational nor enlightened, but there it is.) Euler became a vocal apologist, speaking publicly in debates and writing a variety of papers refuting those who opposed Christ.  

In private life he was faithful in church attendance, prayed daily with his family at home, and knew his Bible well. His marriage to Katharina Gsell lasted nearly 40 years, during which time they buried eight small and two adult children. (Three of his thirteen children outlived him.) He appears to have loved his children, teaching them on their own level, inventing games, and allowing them to be children. He lost one eye to disease early in life and the other, later, to a cataract. Nearly blind for the last seventeen years of his life, he remained extraordinarily productive, dictating to scribes and continuing to publish until his death in 1783. Suffering appears to have turned him more closely to God. People described him as gentle, humble, professionally generous to other scholars, and giving credit easily to colleagues. Unpretentious, witty, sometimes sarcastic, he readily marveled at the Lord’s creation and the beauty of the created order, beauty that captivated his imagination and set him to work.     

For more: