# Portraits of Christians – Leonhard Euler

In a time when our culture wants to denigrate Christians as stupid, backwards, anti-intellectual cretins opposed to science, I’d like to refresh our culture’s  memory with some portraits of some of the phenomenal, ground-breaking people who helped our science – and our society – advance. Not only did these people happen to be Christians, their beliefs were quite often foundational to their achievements.

The name Leonhard Euler (pronounced “oiler”) may not be a household name, but it is one familiar to many engineers. The Euler-Bernoulli Beam theory he developed with his friend Daniel Bernoulli became a cornerstone of structural engineering, and we still use the “Euler buckling stress” in column compression calculations 2 centuries after he died.  But his contributions to engineering were only a small part of his amazing résumé. Besides being considered one of the greatest mathematicians of all time and the top mathematician of the 1700’s, he also advanced the fields of physics, astronomy, and logic. If you’ve ever seen the symbol “e” (the base of the natural logarithm) on a calculator, you’ve seen one of 2 mathematical constants named after him (the only mathematician with that distinction). In math, he contributed to the fields of calculus, geometry, algebra, graph theory, and number theory. Science historian Carl Boyer compared the impact of his book on mathematical functions to Euclid’s Elements; Euclid’s being the foremost textbook of ancient times, and Euler’s the foremost of modern times. He won the Paris Academy’s Prize Problem (an international problem-solving competition of the 1700’s) 12 times. He extended Newton’s laws of particle motion to include rigid bodies. In logic, he came up with the graphical representation of a syllogism now known as an Euler diagram. Much of our math notation (such as the Greek letter Σ for summation) is due to him. If you’ve taken a math class anywhere between junior high and grad school, any general physics class, or any of several different engineering courses, you’ve been helped by (or, depending on your perspective, been tortured by) Euler’s analytical brilliance. Although the term isn’t used much anymore, Euler was a true “polymath” – one with expertise in a wide variety of subjects.

His credentials as a genius are unquestionable. And yet, he was also a devout Christian. He pushed the boundaries of math and science, and yet never felt that science had led him away from God.  In fact, he wrote an impassioned “Defense of the Revelation Against the Objections of Freethinkers”, a treatise against the atheists of his day. This is a roughly 14 page work laid out in 53 paragraph-length points to build a case that true happiness is only achieved through knowing and obeying God, and that the Bible is God’s gift to us to show us how to achieve that. He postulates that the human soul is exemplified by the exercise of understanding and will; that happiness consists in the “perfection”, or betterment, of a situation; that for humans,  the complete happiness of their soul depends on perfecting these two faculties of the soul – understanding and will. With regard to the first, Euler proposes, “The perfection of understanding consists of the knowledge of truth, from which is simultaneously born the knowledge of good.  The principal aim of this knowledge is God and His works, since all other truths to which reflection can lead mankind end with the Supreme Being and His works.” Regarding the second, he says that “the will of man should submit to the will of God in all respects and with the greatest exactitude.  Since God is the source of all good, it is obvious that the man who wishes to bend his will in this way must necessarily be in the happiest state.”[1] He goes on to (briefly) answer a wide range of objections to why the Bible is God’s road map to lead us to Himself.

After being asked to tutor Frederick the Great’s niece, he wrote 200 letters to her explaining physics and philosophy, but also delving into his Christian knowledge as foundational premises to his understanding of the world. Note, these are not compartmentalized statements of personal faith separate from his science and philosophy lessons. For instance, in explaining about the marvels of the eye to her, which was only then just beginning to be studied in detail, he wrote, “Though we are very far short of a perfect knowledge of the subject, the little we do know of it is more than sufficient to convince us of the power and wisdom of the Creator. We discover in the structure of the eye perfections which the most exalted genius could never have imagined.”[2] This coming from a genuine genius! Ironically, two centuries after Euler recognized it, we are still learning more about the complexity and amazing design demonstrated in the human eye (see my previous post on that topic here). I could go on with several other examples of the faith of this intellectual giant, but I’ll stop here and just say that Euler was one of many great scientists through the centuries who delighted in the study of God’s creation, and clearly recognized it as such. Do you?

[1]Leonhard Euler, “Defense of the Revelation Against the Objections of Freethinkers”, c.1740’s.
[2] Leonhard Euler, Letters to a German Princess on Diverse Subjects of Natural Philosophy, “Letter XLI”, written 1768-1772.