Scientist and Saint: Blessed Niels Stensen (1638-1686)

For many people today, the controversy over the Catholic Church’s treatment of Galileo Galilei has only one lesson: faith and science are incompatible. After all, according to this argument, consider how the Church treated a brilliant scientist with innovative ideas in the seventeenth century. How can faith in Jesus Christ coexist with the quest for scientific truth?

Setting aside a discussion of the Galileo affair itself,¹ another brilliant seventeenth-century scientist can help us gain some perspective on the relationship between faith and science. And this scientist, unlike Galileo, was recognized by both friends and enemies for his holiness.

Niels Stensen² was born into a Lutheran family in 1638 in Copenhagen, Denmark. He studied at the University of Copenhagen at the age of nineteen, but afterwards he traveled to the Netherlands to further his studies of his favorite subject: anatomy. During this time, Stensen learned from—and studied with—some of the best scientists of the day.

Stensen’s careful observations of anatomy over the next several years led him to make so many discoveries that it’s not surprising that various parts of the body were later named after him. Students of anatomy are now taught how to identify Stensen veins, Stensen’s foramen, and (one of his first discoveries) Stensen’s duct. As a result of his studies, he proposed multiple conclusions that were contrary to common assumptions of the day. He discovered the circulation of blood in the human body. He disagreed with the theory that tears were produced by the brain. He claimed that the heart was simply a muscle. And he was right.

His insatiable curiosity led him into the fields now known as paleontology, crystallography, geology, and stratigraphy. After studying the head of a large shark, he recognized the connection between the teeth he found in the shark’s head and the “tongue stones” found in rock formations. How could the teeth of a fish end up in solid rock? Although Stensen was not the first person to recognize that the fossils found in rocks came from living organisms, he is credited with discovering some of the foundational principles of the science of stratigraphy. Stensen’s conclusions about layers, or strata, found in rocks paved the way for later theories about deposition, erosion, and other concepts that can be found even in children’s science textbooks today.

Stensen held many important positions, such as a professor of anatomy and physician to a duke, as he traveled and worked all over Europe. But all that changed when he decided to change his faith.

Stensen had had doubts about the Lutheran faith when he was still living in the Netherlands. Over the years, he took his doubts and questions to, among other people, a Jesuit priest. While in Italy, he also witnessed a Eucharistic procession on the streets of Livorno, which sparked even more questions in his mind about the Catholic faith. Although the process took years, his doubts finally led to a certainty; in 1667, he entered the Catholic Church.

At the time, he was only twenty-nine years old and was widely known for his scientific achievements. But becoming a Catholic cut him off from many career paths. For example, although his native Denmark wanted him back, he was not allowed to be officially named a professor in that country because he was a Catholic; he had to be given a different title instead. He also apparently experienced the subtle and not-so-subtle persecution of Catholics living in Protestant countries, a persecution which was particularly common at the time.

But that did not appear to bother him. Stensen simply transferred the energy he had poured into the physical sciences into his new passion: God and theology. In 1675, he became a Catholic priest. Two years later, he was nominated to become a bishop. Stensen served as an auxiliary bishop and an apostolic vicar for the rest of his life in an area that was considered mission territory for Catholics at the time: the region north of Germany.

Stensen did not treat his ordination to the priesthood or the episcopacy as a mere intellectual pastime. Instead, he took his role as shepherd very seriously. He lived a self-disciplined and simple personal life. He wrote several books on asceticism and theology. He generously served the poor, literally giving the clothes off his back to those in need.

Many of the rich and powerful in the world, those who had fawned over his scientific brilliance in the past, now mocked him over his tawdry clothes and penitential way of life. To them, it was inexplicable that anyone should choose the Catholic Church and self-imposed poverty over a more profitable religious allegiance and scientific honors. Why choose hard work and hiddenness over fame and fortune? But that choice, after all, is simply the same old choice of God versus mammon, a choice which our Lord Himself warned us about.³ Stensen died at the age of forty-eight, worn out by years of giving everything to others.

But that is precisely why Pope John Paul II beatified him in 1988 and why the Church now calls this man Blessed Niels Stensen. Blessed Niels knew that his years of searching for truth—both scientific and theological—were all part of the mission to which God had called him. Many of his theories, initially controversial and hotly debated, have since become common knowledge.

Science and faith are not incompatible. The study of the natural world and the study of God are just as compatible in the world today as they were in the seventeenth century. Men like Blessed Niels show us that it will always be controversial to seek God and follow His truth wherever it leads, but it is also exactly what we are all called to do.

• Related at CWR: “Revisiting and understanding the ‘Galileo Affair’: An interview with Dom Paschal Scotti” (Nov 16, 2017)

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