Christian History Magazine Collection

The convoluted tale of a faithful Catholic caught in a web of theological inflexibility, papal power, and his on political naivete.

by Virginia Stem Owens from Christian History magazine no. 76

Say the name Galileo, and most people picture the astronomer standing before scowling Inquisition judges, forced to recant his claim that the earth revolves about the sun.

To secular scholars, Galileo Galilei (1564-1642) was a martyr to religious bigotry, demonstrating how pious superstition can shackle human knowledge. To Protestant historians, Galileo’s fate is a sharp contrast to the freedom other Enlightenment luminaries, like Robert Boyle, Isaac Newton, and Johannes Kepler, enjoyed in Reformation regions.

But there’s more to Galileo’s story. Born in 1564 into a Europe passionate—and passionately divided—about its faith, the astronomer experimented, observed, and published his findings without ecclesiastical restraint for almost seventy years before his run-in with the papal authorities. He lived and died just as faithful to the Roman Church as Boyle was to the Anglican or Kepler to his Lutheran roots.

This stands in contrast to the network of thinkers and tinkerers, self-styled “the New Philosophers,” who would help bring the scientific revolution to full flower. Many of those men paid little attention to the commitments of nationality or religion that divided their contemporaries. They considered themselves citizens of a borderless and nonsectarian commonwealth of science. Indeed, for some, their allegiance to the pursuit of verifiable truths about the natural world superseded all other commitments. The Dutch mathematician and physicist Christiaan Huygens, for example, declared, “The World is my Fatherland, Science is my Religion.”

Despite Galileo’s faithfulness to his church, he is most often portrayed today as a secular scientific hero who stood firm against religious bigotry. His loyalty to his faith is largely ignored. Internationally famous by middle age, he might easily have found more intellectual freedom in England or the Dutch states or even in the French court. Yet he remained in Italy and submitted to an Inquisition he considered ignorant and a pope who used him as a political pawn.

Astronomy’s New Star

Galileo’s career launched in 1604, when he demonstrated that a new star, a supernova, was further away than the moon. This may strike the modern reader as fairly obvious, but the cosmological implications for the early seventeenth century were enormous. His study of the new star confirmed his growing belief in a Copernican—heliocentric—universe.

During this same year, Galileo began pursuing a fruitful patronage relationship by buttering up Cosimo II de Médici, who was slated to inherit his father’s title as Grand Duke of Tuscany. The struggling academic dedicated one of his new inventions, a geometric and military compass, to Cosimo. Five more years would go by, however, before the old duke obliged his scion (and gave hope to the astronomer) by dying.

Meanwhile, Galileo supplemented his income by selling his newly invented compass to students, along with a handbook on how to use it. He also invented a primitive thermometer and a barometer. He wrote voluminously, notably on the long-debated phenomenon of motion.

When Cosimo II married in 1608, Galileo produced, as a kind of wedding present for his future patron, a 56-ounce lodestone (magnet) capable of lifting over twice its weight in iron. The astronomer proposed the lodestone as a fitting emblem of Cosimo’s own strength and powers of attraction.

The following year, two events occurred that would change Galileo’s future. First, the old Duke of Tuscany died, leaving the way clear for his son to assume his position.

Second, Galileo heard of a Dutch invention, a “spyglass,” which brought far distant objects near. Galileo set to work and, by the end of the year, produced his own version with much greater magnification.

Early in January 1610, Galileo made a number of discoveries, using the spyglass he continued to upgrade. He found mountains on the moon, saw that the Milky Way was actually composed of stars, and discovered four satellites around Jupiter, which he named the “Medician stars.” He published these findings in a paper titled “The Starry Messenger,” which, of course, he dedicated to the new Grand Duke Cosimo II.

Ousting Aristotle

His discovery and publication brought him the long-dreamed-of appointment as Cosimo’s court mathematician. But as Galileo’s fame grew, so did powerful opposition to his work, as it began to shake the foundations of a worldview based on Aristotle’s assumptions about the cosmos.

The common understanding was that the universe was a set of nested concentric spheres, with our own planet at the center. Our moon was recognized as a satellite undergoing constant change, but the objects in the spheres beyond were immutable—an aspect of their perfection, according to Aristotle.

But Galileo, with his fascination for mathematics, insisted that the same measurements that worked on earth applied also to celestial spheres. He had already proved by verifiable experiment that Aristotle was wrong about falling objects. Now he further embarrassed Aristotelians by intervening in the effort to cast a new bell for Florence’s city tower.

The city fathers of Florence, impressed with Galileo’s steadily increasing fame, commissioned him to find a way to cast a new bell for the town. None of the local craftsmen could understand why the wooden mold for the bell’s inner surface kept rising when molten metal was poured between it and the mold for the outer surface. Taking his cue from the ancient Greek Archimedes, Galileo explained that bodies must be heavier than the volume of liquid they displace or they will float to the surface. This refuted Aristotle, who claimed objects floated when they “pierced” the skin of a liquid and escaped from it. By increasing the pressure on the inner mold, the Florence bell-casters succeeded in their task.

So grateful were the city fathers for Galileo’s solution to their problem that they held a state dinner at which the entertainment was a debate between Galileo and visiting clergy on the Aristotelian doctrine regarding liquids.

Among the guests was Cardinal Mafeo Barberini, who was impressed enough with Galileo that when he returned to Rome, he championed the astronomer’s revolutionary ideas at the papal court.

Neither Barberini nor Galileo could foresee how their initially friendly relationship would change in the years to come.