In the sixteenth century the Reformation introduced a new idea. This was the notion that knowledge is not simply the province of ecclesiastical institutions but that, especially when it comes to matters of conscience, each man should decide for himself. The “priesthood of the individual believer” was an immensely powerful notion because it rejected the papal hierarchy, and by implication all institutional hierarchy as well. Ultimately it was a charter of independent thought, carried out not by institutions but by individuals. The early Protestants didn’t know it, but they were introducing new theological concepts that would give new vitality to the emerging scientific culture of Europe.

Here is a partial list of leading scientists who were Christian: Copernicus, Kepler, Galileo, Brahe, Descartes, Boyle, Newton, Leibniz, Gassendi, Pascal, Mersenne, Cuvier, Harvey, Dalton, Faraday, Herschel, Joule, Lyell, Lavoisier, Priestley, Kelvin, Ohm, Ampere, Steno, Pasteur, Maxwell, Planck, Mendel. A good number of these scientists were clergymen. Gassendi and Mersenne were priests. So was Georges Lemaitre, the Belgian astronomer who first proposed the “big bang” theory for the origin of the universe. Mendel, whose discovery of the principles of heredity would provide vital support for the theory of evolution, spent his entire adult life as a monk in an Augustinian monastery. Where would modern science be without these men? Some were Protestant and some were Catholic, but all saw their scientific vocation in distinctively Christian terms.

Copernicus, who was a canon in the cathedral of Krakow, celebrated astronomy as “a science more divine than human” and viewed his heliocentric theory as revealing God’s grand scheme for the cosmos. Boyle was a pious Anglican who declared scientists to be on a divinely appointed mission to serve as “priests of the book of nature:’ Boyle’s work includes both scientific studies and theological treatises. In his will he left money to fund a series of lectures combating atheism. Newton was virtually a Christian mystic who wrote long commentaries on biblical prophecy from both the book of Daniel and the book of Revelation. Perhaps the greatest scientist of all time, Newton viewed his discoveries as showing the creative genius of God’s handiwork in nature. “This most beautiful system of sun, planets, and comets,” he wrote, “could only proceed from the counsel and domin- ion of an intelligent and powerful being.” Newton’s God was not a divine watchmaker who wound up the universe and then withdrew from it. Rather, God was an active agent sustaining the heavenly bodies in their positions and solicitous of His special creation, man.

The example of Kepler shows that the Christian convictions of these towering figures of science were not incidental to their work. Rather, these convictions were the scientists’ guiding inspiration. “For a long time.” Kepler wrote, “I wanted to become a theologian. Now, however, behold how through my effort God is being celebrated through astronomy.” A strong advocate of Copernicus’s heliocentrism, Kepler held that the sun- centered cosmos was an image of the Holy Trinity, with God represented by the sun, Christ by the stars and planets, and the Holy Spirit by the motions of the heavenly bodies.” When Kepler discovered that planets do not move in circular but rather in elliptical orbits, he was criticized by some theologians as rejecting the beauty of God’s creative plan. These theologians reasoned that surely God would have used perfect circles to choreograph the planetary motions!

Kepler, however, was certain, based on his deep Christian faith, that God had employed an even more beautiful pattern, and he labored hard to decipher it. When he discovered what it was—his three laws of planetary motion—he experienced something of a spiritual epiphany. Kepler announced that his laws showed that God had used a far simpler and more elegant scheme than the one previously delineated in the Ptolemaic system of cycles and epicycles. In a prayer concluding The Harmony of the World, Kepler implored God “graciously to cause that these demonstrations may lead to thy glory and to the salvation of souls.”