69: The Scientist and The Church: Politics, Piety, and the Persecution of Galileo

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Transcript of Galileo’s Trial before the Inquisition, 1633
“Inquisitor: You say you came to Rome to be able to have the truth about the said matter; say also what was the outcome of this business.
Galileo: Concerning the controversy that went on about the said opinion of the stability of the sun and motion of the earth it was determined by the Holy Congregation of the Index that such an opinion, taken absolutely, is repugnant to Holy Scripture, and it is only to be admitted hypothetically, the way in which Copernicus took it.”

Few historical conflicts have been as widely misunderstood as Galileo Galilei's clash with the Catholic Church. This confrontation, culminating in Galileo's 1633 trial before the Inquisition, represents more than a simple battle between scientific progress and religious dogma. Instead, it illustrates the complex interplay of scientific discovery, theological interpretation, institutional politics, and personal rivalries. Galileo's story is one where scientific disagreement became entangled with religious controversy, amplified by his confrontational personality, and complicated by the turbulent religious politics of Counter-Reformation Europe.

Galileo's conflict with the Church began to take shape soon after he was appointed "philosopher" to the Grand Duke of Tuscany in 1610. This prestigious position elevated Galileo's status in Renaissance society and provided him with financial security and political protection. The telescope, still a completely unprecedented instrument in astronomical observation, had already enabled Galileo to make revolutionary observations of the moon's surface, Jupiter's moons, and the phases of Venus.

Traditional astronomy had relied on angle-measuring instruments based on the 360-degree circle, making the telescope's direct observation through manipulated light a fundamental methodological shift. As discussed in the last episode, this novelty created legitimate scientific skepticism among established Aristotelian philosophers, some of whom refused to look through Galileo's telescope during his visit to Padua in August 1610. Their resistance wasn't merely dogmatic opposition but reflected genuine concerns about the reliability of this new observational tool.

Between 1611 and 1613, Galileo's discovery and interpretation of sunspots led to significant controversy, particularly with the Jesuit astronomer Father Christopher Scheiner. While ostensibly scientific, this dispute established a pattern of conflict with the Jesuits that would have serious repercussions for Galileo later. Galileo openly declared his Copernican allegiance after 1613, moving from a position of cautious interest to outright advocacy for heliocentrism as physical reality.

This transition occurred at a precarious moment. While the Catholic Church had initially shown interest in Copernican theory, by the 1610s, concerns had grown about its apparent contradiction of Scripture. Tensions escalated as Galileo increasingly positioned himself as not merely an astronomical observer but someone qualified to interpret the theological implications of his discoveries.

The religious landscape had transformed dramatically between Copernicus and Galileo. In Copernicus's time, the Reformation was still relatively new, with many hoping for eventual reconciliation between Catholics and Protestants. Figures like Erasmus maintained Catholic identity while acknowledging Reformers' valid points.

By 1610, however, the possibility of reconciliation between Rome and Protestant centers seemed impossible. Religious violence had escalated, including the St. Bartholomew's Day Massacre (1572) of Huguenot Protestants in Paris. English Catholics faced persecution under Elizabeth I and James I. The Council of Trent (1545-1563) had systematically addressed Catholic doctrine and reform, hardening theological positions.

What began as debates following Luther's 95 Theses in 1517 had transformed into hostile "stand-offs" between opposing theological camps. The Jesuits, or Society of Jesus, were founded by Ignatius of Loyola in 1540.  They became known for their educational institutions, missionary work, intellectual pursuits, and distinctive fourth vow of special obedience to the Pope regarding missions. The Jesuits' missionary work represented an aggressive strategy to win converts back to Catholicism. By the early 17th century, theological disagreements frequently escalated to military conflicts, with the New World becoming a battleground for souls between Catholic and Protestant missionaries.

Within this charged environment, several biblical passages challenged the Copernican model. Joshua 10, which describes the sun standing still, implied that the sun normally moved around the Earth. Psalms 93:1 and 104:5 suggested that the Earth was fixed and immovable. The Council of Trent had emphasized the "plain meaning" of Scripture, making these passages particularly problematic for heliocentric theories.

The controversy intensified following a dinner at the Florentine Court in December 1613. Benedictine monk Benedetto Castelli, a former pupil of Galileo, wrote to his mentor about discussions concerning heliocentrism's compatibility with Scripture. Galileo's response to Castelli, later expanded into the "Letter to the Grand Duchess Christina," marked his entry into theological territory despite his lack of formal training in this area.

Galileo's "Letter to the Grand Duchess Christina" presented several enduring theological arguments. Most importantly, he proposed the "two books" analogy: God authored both Scripture (the Book of God's Word) and nature (the Book of God's Works), which cannot contradict each other. Galileo argued that Scripture wasn't intended to explain natural phenomena, drawing on St. Augustine's precedent.

Augustine had cautioned against literal interpretations of biblical passages when they contradicted established natural knowledge, warning Christians not to appear foolish to educated pagans. Galileo referenced this approach. He quoted "an ecclesiastic of the most eminent degree"  who stated, “the intention of the Holy Ghost is to teach us how one goes to heaven, not how heaven goes."

Cardinal Roberto Bellarmine, a leading intellectual figure in the Catholic Church, played a crucial role in the Church's response to Galileo. In April 1615, Bellarmine sent a detailed reply to Father Paolo Antonio Foscarini, who had published a defense of Copernicanism. Bellarmine's letter represents the Church's position: openness to heliocentrism as a hypothesis but resistance to it as proven physical reality without conclusive evidence.

This position was not merely dogmatic; it reflected the genuine lack of observable proof for Earth's motion at that time. Bellarmine even acknowledged that if conclusive proof of heliocentrism emerged, Scripture would need to be reinterpreted—but he saw no such evidence in 1615. This measured response demonstrates that the Church's concern with intellectual rigor led them to demand conclusive proof before accepting a theory contradicting both Scripture and the prevailing scientific consensus.

Galileo's "natural pugnacity" and confrontational style in advancing scientific arguments significantly contributed to his troubles. His writings often contained "good Tuscan abuse," and he "could never resist giving a few extra kicks" to perceived opponents. This approach transformed scientific disagreements into personal rivalries and created lasting enemies.

The dispute with Father Orazio Grassi of the Jesuit College exemplifies this pattern. In 1619, Grassi published a lecture concluding that comets were burning bodies beyond the moon. Galileo responded by ghost-writing the "Discourse on the Comets,” dismissing comets as "insubstantial, vaporous bodies scarcely worth serious astronomical attention."

Ironically, Father Grassi's analysis came "much closer to the truth" than Galileo's position. Modern science confirms that comets do indeed move in curved orbits and exist in interplanetary space far beyond the moon, as Grassi suggested. This episode demonstrates that Galileo's judgment could be clouded by rivalry and polemics, particularly "when out to discredit a rival."

Galileo's harsh criticism of Father Grassi created lasting enemies within the Jesuit Order, who would later play a role in his 1633 trial. The contrast between Galileo's approach and the more diplomatic styles of his contemporaries highlights how his personality contributed to escalating conflicts beyond purely scientific disputes.

In late 1615, Galileo traveled to Rome to advance the heliocentric cause and discredit Father Tommaso Caccini, who had preached against him. This decision represented a significant miscalculation. Historian Antonio Banfi noted that Galileo's confidence was "far from justified considering the circumstances."

On February 19, 1616, the Holy Inquisition appointed a Commission to investigate heliocentrism. Five days later, the Commission reported adversely on the theory, calling it "foolish and absurd in philosophy" and contradictory to Scripture. Pope Paul V asked Cardinal Bellarmine to tell Galileo to abandon the Copernican theory, and in early March, the Index of Prohibited Books formally condemned heliocentrism.

Despite these setbacks, Galileo met with Pope Paul V for a 45-minute "most friendly personal audience" on March 11, 1616. On May 26, 1616, Cardinal Bellarmine issued a certificate at Galileo's request, clarifying that he had not been forced to recant or do penance. However, it reinforced the prohibition against defending heliocentrism as physical reality while leaving open the possibility of discussing it as a mathematical hypothesis.

This ambiguity about what Galileo could or could not say would become crucial in the events leading to his trial in 1633. The Church's position had a defensible intellectual basis. Given the available evidence in 1616, heliocentrism remained unproven, and Galileo was making "the blind leap of faith from theory to presumed fact." 

Like other royal courts of the era, the Vatican was "a hotbed of intrigue." Competing interest groups, including Aristotelian philosophers and Jesuits hostile to Galileo, operated within this political environment. National factions (Italian, German, French, Spanish) created internal divisions within the Catholic hierarchy.

By the 1620s, the Thirty Years War had further entrenched religious-political divisions. Pope Urban VIII would face accusations of insufficient zeal against Protestants and favoritism toward France. The Spanish Cardinal Gaspar de Borja's personal conflicts with Pope Urban VIII illustrate how the Catholic world was far from unified, with national and political loyalties often superseding religious solidarity.

These political divisions provided the backdrop against which Galileo's scientific claims were evaluated and ultimately condemned. The Church's initial openness to Copernican theory had given way to increased vigilance against any ideas that might undermine Catholic orthodoxy in the face of Protestant challenges. Galileo's case thus became entangled in larger geopolitical and religious conflicts that transcended purely scientific considerations.

The election of Maffeo Barberini as Pope Urban VIII in August 1623 marked a significant turning point for Galileo. Unlike his predecessor, Paul V, Urban was deeply interested in scientific and intellectual matters. As a cardinal, Barberini had opposed the 1616 condemnation of Copernicus. As pope, he granted Galileo six long audiences in the spring of 1624, speaking of him as a "great man whose fame shines in the heavens."

This favorable relationship encouraged Galileo to begin work on his "Dialogue Concerning the Two Chief Systems of the World," which would be published in February 1632. The Dialogue took the form of a conversation among three characters: Salviati (representing Galileo's views), Sagredo (an intelligent layman), and Simplicio (defending the Aristotelian position). This structure allowed Galileo to present arguments for and against different cosmological systems.

However, the Dialogue's literary structure revealed a clear bias. Salviati and Sagredo, the two Copernican sympathizers, were depicted as intelligent and persuasive, while Simplicio, whose "loaded name" suggested simplicity or foolishness, presented weak arguments for the Aristotelian view. Galileo's felicitous, seductive, and often amusing literary style enhanced this imbalance, using insulting terms like "dumb idiots" and "mental pygmies" for geocentricists.

A crucial strategic error was Galileo's deliberate omission of a serious discussion of the Tychonic system, which incorporated elements of both Ptolemaic and Copernican models and was widely accepted by Jesuits and many astronomers as best fitting the available evidence in 1632. By focusing exclusively on the Ptolemaic and Copernican systems, Galileo created a false dichotomy that made the Copernican position appear stronger than it would have if compared to Tycho's model.

Perhaps most significantly, the Dialogue contained no new scientific evidence beyond what was available in 1613. What made it controversial was not new discoveries but its rhetorical structure and polemical approach. By heavily favoring the Copernican position while making Simplicio appear foolish, Galileo created a text that could easily be interpreted as violating the 1616 prohibition.

The Dialogue was initially well-received upon publication in Florence, but sales were quickly suspended as complaints reached Rome. Pope Urban VIII, once Galileo's admirer, became increasingly angered by what he perceived as Galileo's betrayal. The dramatic shift in the Pope's attitude suggests factors beyond the scientific content were at play.

Vatican court politics allowed Galileo’s enemies to turn the Pope against him. When the Dialogue was published, these enemies "probably rubbed their hands and smiled," seeing it as "the rope by which they could...hang the mischievous Florentine astronomer at last."

The Aristotelian philosophers and Jesuits who had long resented Galileo's harsh polemics now found an opportunity for revenge. They exploited tensions between Spain and the Vatican. Cardinal Borja publicly humiliated the Pope during a consistory in March 1632 by accusing him of failing to defend Catholicism adequately. The Pope, concerned about his reputation amid these political challenges, became less willing to protect Galileo.

On October 1, 1632, Galileo was summoned to Rome for examination. He attempted to avoid the journey, citing his advanced age (68) and poor health, but these excuses were rejected. In early 1633, he traveled to Rome in Grand Duke Ferdinand's litter, arriving for what would become one of history's most famous trials.

Galileo's trial began on April 12, 1633, under the jurisdiction of the Holy Inquisition. The legal basis of the case centered not on the scientific validity of heliocentrism but on Galileo's alleged disobedience of the 1616 prohibition. A critical discrepancy emerged between Bellarmine's certificate to Galileo (which mentioned only teaching or defending heliocentrism as physical reality) and the official record (which suggested a more comprehensive prohibition against discussing it at all).

This ambiguity created a central question: "Could Galileo discuss heliocentrism as an abstract model or theory, or could he not discuss it at all?" The interrogation focused on Galileo's intentions in writing the Dialogue. Had he merely presented Copernicanism hypothetically, as permitted, or had he defended it as physical reality, as prohibited?

Galileo's defense strategy involved claiming he had presented Copernicanism hypothetically rather than assertively. However, the Dialogue's rhetorical structure clearly favored the Copernican view, undermining this claim. On April 17, 1633, Galileo was examined further, and by April 28, Cardinal Francesco Barberini (the Pope’s nephew) reported that Galileo "recognized that he had gone too far and erred."

Pope Urban VIII personally intervened in the case, insisting that the final judgment include Galileo explicitly abjuring the opinion that the Earth moves. The case concluded with the final judgment on June 21-22, 1633. Galileo was declared a heretic, sentenced to imprisonment (later commuted to house arrest), and his Dialogue was banned.

On June 22, 1633, Galileo formally recanted, reading a prepared statement: "I, Galileo, son of the late Vincenzio Galilei of Florence, aged 70 years... swear that I have always believed, I believe now, and with God's help I will believe in the future all that the Holy Catholic and Apostolic Church holds, preaches, and teaches..." He continued by explicitly abjuring the "error and heresy of the movement of the Earth."

The legend that Galileo muttered "Eppur si muove" ("And yet it moves") after his recantation is almost certainly apocryphal, first appearing in historical accounts much later. What is clear is that Galileo's "heresy was one of disobedience: of openly teaching something he had supposedly been explicitly told not to teach." Notably, "at no point in his trial was his basic doctrinal sincerity as a Catholic Christian even called into question."

Following his trial, Galileo stayed with Archbishop Ascanio Piccolomini of Siena for a recuperative period before settling at Arcetri near Florence under house arrest. This arrangement demonstrates the "non-monolithic nature of the ecclesiastical hierarchy," as some Church officials continued to support Galileo despite his formal condemnation.

Remarkably, Galileo's house arrest proved intellectually productive. He continued scientific work, discovering the moon's axial "libration" and designing pendulum clock improvements. Most significantly, he completed "Discourses Concerning Two New Sciences" in 1638, which became "one of the foundational texts of experimental physics." The fact that this work was published in Leiden, Holland, indicates the continued international interest in Galileo's ideas and his ability to circumvent publication restrictions in Catholic territories.

An interesting footnote to the case involves the Spanish Inquisition, which refused to post notices of Galileo's condemnation. This refusal reflected not sympathy for Galileo's ideas but rather Spanish resentment of Vatican interference in their domestic affairs, illustrating how Galileo's case became entangled in broader geopolitical tensions.

Despite these challenges, Galileo maintained an intellectual community through relationships with his daughter Sister Maria Celeste, his pupil Vincenzo Viviani (who became his biographer), and possibly visitors like Thomas Hobbes and John Milton. These connections sustained his scientific work until his death at Arcetri in 1642.

The Galileo affair resists simplistic "hero versus persecutors" narratives. Both sides made errors: Galileo "went 'too far' and pushed the boundaries," while some Church officials responded with "arrogance and personal fury." Understanding this complex history requires acknowledging Galileo's overreach and the Church's inappropriate anger.

The case demonstrates how scientific disputes become entangled with theological, political, and personal factors. Galileo's confrontational personality transformed scientific disagreements into bitter rivalries, while the Church's response reflected not just theological concerns but internal politics and broader Counter-Reformation anxieties.

This nuanced understanding of the Galileo affair offers valuable insights into the complex relationship between innovation and tradition, revealing how institutional resistance to new ideas often stems from multiple motivations beyond simple dogmatism. Galileo's legacy lies not just in his scientific discoveries but in illuminating the complex social, political, and institutional contexts in which scientific progress occurs.

Our next episode will travel to the other side of the world, where a bit of irony was being played out.  While Galileo was being condemned, Jesuit missionaries introduced telescopes and heliocentrism to the Ming Dynasty of China.  Yet this wasn’t just about science.  It was also about cultural exchange and conflict that marked the meeting of East and West during the early modern period.

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