Reflections on the Galileo Effect- Was the Galileo Affair a Conflict between Science and Religion?

August 2017 Feature

The arrest of Galileo Galilei for proposing a sun-centered model of the universe despite being told not to has been cited as an embarrassing example of the inevitable conflict between the forward-looking nature of science and regressive character of religion.

This article will offer a brief recounting of this episode in order to show the difficulty of drawing simplistic conclusions concerning religion’s conflicting or cooperative relationship with science at the time. It will then mention some lessons the episode can offer us today.

Galileo, who lived in the 16th and 17th centuries, made seminal contributions to physics, engineering, and astronomy. With the creation of a superior telescope, his corresponding observations led him to favour the physical reality of a sun-centered Copernican model of the universe, whose mathematical calculations he had already favoured beforehand.

The Catholic Church had previously accepted the Copernican model insofar as it was a useful  predictive mathematical tool that did not otherwise assert that the sun must be at the center of the universe. Instead, the Church and many astronomers accepted the physical reality of an earth-centered model of the universe based on Aristotelian physics.

Aristotelian physics conceived reality as composed of five elements, four of which consist of inferior material which tended to the center of the universe, that is, earth, which was unmoving. The fifth element, quintessence, an incorruptible and unchanging material, was what made the heavenly bodies and determined that they revolve around the earth in perfect circles for eternity.

Galileo’s observations revealed to him, among other things, that the surface of the sun and moon were not perfect, as quintessence would have it; and that Jupiter had four moons, which indicated that the heavenly bodies did not all revolve around the earth.

He published these findings indicating his preference for the Copernican model in 1610 and 1613. This led Holy Office – the office charged with ensuring orthodoxy – to declare the implications of these findings false.

Many scientists disagreed with Galileo as well. They argued that the Copernican model could not yield superior predictions to the earth-centered model partly because both assumed circular rather than elliptical orbits. They also argued, wrongly – because they did not have powerful enough measurement equipment at the time – that stellar parallax, which should be observable if the earth was moving, could not, in fact, be observed.

However, by 1613 and 1615, he had already sent out widely circulated defending the Copernican model on scriptural grounds.

In the letters, he relied heavily on the interpretive principles of the Church Fathers, especially Saint Augustine’s concept of “accommodation,” which is the idea that the scriptures have been written to accommodate the mind of the common person, giving priority and clarity to matters pertaining to salvation, not to scientifically robust descriptions of reality.

The verses which had been appealed to in support of the Aristotelian model included Joshua 10.13, Psalm 19.4-6; 93.1; 96.10; 104.5; 119.90; Ecclesiastes 1.5, and I Chronicles 16.30.

Unfortunately, by engaging with scriptural interpretation, he was treading on thin ice. The Church had been embroiled in theological and political conflict with the Protestant Reformers for some time, and had declared at the Council of Trent in 1545-63 that “no one, relying on his own judgment and distorting the Sacred Scriptures according to his own conceptions, shall dare to interpret them contrary to that sense which Holy Mother Church, to whom it belongs to judge their true sense and meaning, had held and does hold.”

Thankfully, Pope Urban VIII, who was a long-time admirer of Galileo’s work, told him in 1624 that he could discuss Copernican theory but only as one hypothesis among others. This emboldened Galileo to, rather unwisely, promote Copernican theory by publishing a fictional dialogue between three individuals about cosmology in 1632. And he gave the name Simplicio, which means someone who is simple-minded, to the advocate of the Aristotelian position, a position which the Pope personally favoured.

In other words, Galileo seemed to be accusing the Pope of being simple-minded in an underhanded way. As one might imagine, the Pope did not take this lightly. He was at the time embroiled in the Thirty-Years’ War, had just switched his allegiance from the French to the Spanish and felt that he needed to come down strong on Galileo to show his new allies his authority and decisiveness.

Thus, in 1633, he was summoned to the Holy Office and found guilty of vehement suspicion of heresy. He was ordered to publicly recant his Copernican astronomy and be confined to his home in Florence where he remained until his death in 1642.

A century later, the Church began the gradual process of publicly shifting their stance toward Galileo. In 1744, Galileo’s Dialogue was republished with the Church’s approval. In 1893, Pope Leo XIII advanced a view concerning the relationship between the scriptures and science in his encyclical like those in Galileo’s letters. Between 1941 and 46, several academic clergymen occasioned a partial and informal rehabilitation of Galileo in their published work. And in 1979, Pope John Paul II initiated the latest informal rehabilitation of him.

From this brief recounting of the episode, it is apparent that interpreting the affair as a conflict between science and religion would be an over-simplification. To appreciate the complexities involved, the minimum factors, of varying weight, that should be considered include the legitimate disagreement among scientists toward Copernican astronomy, the Reformers’ challenge to the Church’s interpretive authority, Pope Urban VIII’s own political troubles, Galileo’s commitment to the primacy of mathematics over Aristotelian physics, and his unwise jab at the Pope.

What can be learned from this episode? We can learn that the relationship between the scriptures and the deliverances of modern science is not a straightforward one. We can also learn to appreciate the different kinds of literary genres in the scriptures and value their theological import without necessarily committing ourselves to their corresponding literal descriptions of reality.


Keith Leong studied Theology and Religion with a focus on science and religion at Durham University and the University of Oxford in the United Kingdom from 2013-2016. He is a member of St Andrew’s Cathedral, Singapore.