Science and Religion

The Galileo Affair

Alongside the Crusades and the Spanish Inquisition, the Galileo Affair stands as a dark passage in the History of the Catholic Church. The image of Galileo as an enlightened scientific visionary, throttled and broken by catholic dogma is firmly held in popular culture and symbolizes a celebrated parting of the ways between science and religion that persists even today.

For many the beginning of “modern Science” is often associated with Galileo, the beginning of a pure pursuit of science, free of religious constraint.

The statement above made by John Paul II in 1979 expressed a wish to look more closely at the events surrounding the Galileo affair , according to John Paul the disagreement between Galileo and the Church should never have happened and was due to a “tragic mutual incomprehension” (John Paul 1979).

Faith and Science according to the Pope were not mutually exclusive or in conflict, and when properly understood can not fundamentally be at odds with each other. My interpretation of the Popes reasoning here would be based on a belief that both faith and science must be grounded on universal truth, and cannot therefore be at odds with each other, rather only a misunderstanding in the interpretation of that truth.

It was also the “truth” he was seeking in hoping to show that the Galileo incident when laid bare would reveal that the Church had not in fact been the puritanical rejecters of science for which this case had become symbolic.

What were the issues between religion and science in the Galileo affair?

Science, Ptolemy and Copernicus:

At its core lay a new paradigm in thinking about the cosmos which was radically different from what had been believed since the time of the Egyptians and Greeks.

In brief the Ptolemaic model had the Earth as the centre of the universe with all heavenly bodies orbiting around it. In contrast the Copernican model was heliocentric, all planets revolving around the sun.

The Ptolemaic model of the solar system had been the unquestioned model of the universe up until and beyond the time of Copernicus. It was lent credibility by Aristotle, in Holy Scripture as well as the mathematical theory of Ptolemy himself.

The Church up until the Galileo incident had (contrary to popular belief) been according to various sources (Brecht,Gingerich,) encouraging of the new sciences albeit with a certain amount of indifference about its importance. Science and mathematics were seen as having no philosophical or theological importance in itself, indeed the position of the heavenly bodies were for most churchmen really only of minor concern in the greater scheme of things.

This was the prevailing attitude of the Catholic Church during the time that the Copernican theory was first received, it was treated as merely an alternate hypothesis to Ptolemy, and it was never viewed as an actual document of heresy and was in fact far more objectionable to the existing academic fraternity and to Protestants than it ever was by the Catholic Church.

Copernicanism arguably became an issue only when Galileo forced the debate away from simple astronomy turning it into a question of theology.

Prior to this the attitude towards science of the catholic community was more one of supportive indifference and not direct opposition to its progress. Copernicus originally delayed publication of his work not for fear of the church, but for fear of ridicule from his academic peers.

Thus the existing religious/scientific climate onto which Galileo would arrive is very different from persecutive and oppressive climate which is often popularly depicted.

First waves:

Galileo’s early work had mainly been in physics where he had famously formulated (amongst other things) the laws of falling bodies and it was in physics where in fact his greatest contributions to science lay.

History and fame however lay in discoveries in astronomy. It was with the telescope that he would be most remembered and would challenge the long held Ptolemaic view of the universe and simultaneously thrust the Copernican view of celestial mechanics into the heart of Christendom.

Through his observations with the telescope, which was actually a Dutch invention for which he has often been mistakenly credited, he made several discoveries which immediately changed astronomical theory.

He observed that like the earth, the moon was made up of mountains and valleys and was not in fact the perfect sphere that is was previously thought to be.

He also observed the moons of Jupiter thus ending the notion that all celestial bodies revolved around the earth.

His observations of sunspots proved that the sun itself revolved on an axis.

Most telling of all were his observations of the phases of Venus, the only possible explanation of which is that Venus moves around the sun and not the earth.

His findings about Venus were later confirmed by the Jesuit astronomer Christopher Clavius, however the Jesuits were not ready to accept the Copernican model and instead opting for the Tycho Brahe model of the cosmos, a system in which all the heavenly bodies barring the earth orbited the Sun, which easily accounted for Galileo’s findings and sat neatly between the Ptolemaic and Copernican models.

Galileo’s discoveries catapulted him as the greatest astronomer of his time and it was observed during this time he was still in favour with the Church, so much so that he was granted an audience with the Pope Paul V in 1611. (Online resource:The Galileo Project)


Rather than building on and returning to purely scientific study, Galileo instead turned his attention to championing the Copernican model and turned a singularly cruel and clever wit against those that did not or would not embrace his ideas.

Accounts of Galileo bear out that his ultimate fate was largely of his own doing, and that any sensible measure of restraint or tact could have avoided his famous collision with the Catholic Church. (Gingerich 1982)

It was his method and dogged manner that set what was in fact a supportive catholic church ultimately and reluctantly against him.

He had through his early success enjoyed a huge measure of good will from the Catholic Church, but through an aggressive and sometimes arrogant manner he managed to antagonise all those that had once regarded him with favour.

Religion and Scripture

The Copernican model of the universe seemed in direct opposition to certain verses in the bible, where if taken in their literal sense quite clearly indicates that the earth is immovable and that the sun (e.g. when Joshua Commanded the sun to stand still) is a moving body in the heavens.

If the Copernican model was true then the literal translation of these particular passages would have to be re-interpreted.

One of the key points here is that contrary to popular belief Galileo did not seek to advance Science alone in the face of religion but sought rather to reconcile science with scripture. It was never his intent to separate religion from science. (Southgate 1999)

Galileo chose to address this issue of scripture in a famous letter to Benedetto Castelli in which he appealed to a broader interpretation of the bible, arguing that while its true that scripture itself cannot err, its interpreters can and have done in many ways.

In essence scripture was not meant to represent strict scientific fact and that the bible was intended as once quoted by a papal cardinal “to teach us how to go to heaven, not how the heavens go” (Woodward 1999)

It would be this pivotal clash of religion, science and scripture that was a key issue in the Galileo affair. By encroaching into the theological stage seeking to re-interpret biblical scripture to fit copernicanism he fell into the hands of the many enemies he had made during his campaign to promote copernicanism.

Politics, Epistomology:

The private interpretation of scripture was a key issue against the Protestants during the reformation and there was very little tolerance of trespass in this area from even as respected a figure as Galileo. This came also at a time when the Vatican was struggling to assert its central authority. (Southgate 1999)

A copy of the letter to Castelli was sent to the inquisition in Rome in 1615 by a Domincan Priest Father Nicolo Lorini who was annoyed at Galileo’s arrogance in re-interpreting the scripture; this coincided with the arrival of another domincan priest Cancinni in Rome (uninvited) to bear witness against Galileo as a heretic.

Neither the letter nor Cancinni’s testimony was enough for the inquisition judges to bring a case against Galileo, despite mounting pressure against him and despite advice from friends within Rome, Galileo during this time stepped up his campaign for the absolute acceptance of heliocentricity.

Science and Epistemology

In response to this Cardinal Robert Bellarmine one of the most important theologians of the Catholic Reformation entered the fray. In April 1615, he wrote a letter which basically challenged Galileo to prove his theory. In it he reasoned the church could maintain Copernicanism only as a working hypothesis, and that if there was in fact real proof of heliocentricity then they would certainly review teaching literal translations of scripture that were to the contrary.

Galileo’s campaign in the end forced the Church to either accept Copernicanism as fact (which would mean re-interpreting the scriptures) or reject it all together. For Galileo there seemed to be no middle ground.

In the context of the time, the Church’s reluctance to accept Copernicanism seems reasonable given that there was no direct evidence provided by Galileo to back his position and the Tycho Brahe model provided by the Jesuits provided just as logical and a far more convenient explanation for the church.

He crucially could not identify through his observations stellar parallaxes which would have proven Copernicanism, by mapping the position of stars against the changing viewpoint of the sun caused by the earths orbit. His theory of the earth’s tides was flawed and was incorrect in insisting on circular rather than elliptical orbits of planets around the sun. (online resource:The Galileo Project) Galileo himself was perhaps far more compelling than was his actual case.

There too was the real question of how Catholics were supposed to understand the bible and translate the bible based on a proposed theory that could not yet be proved, Galileo was asking the church (ironically) to place its faith in a theory not yet proven in hard fact. A leap of faith that most Catholics were not willing to take.

The church reasonably suggested a position whereby Copernicanism could be accepted as a hypothesis until further proven, a position which Galileo perhaps unreasonably rejected.

Galileo launched his campaign across Europe and despite many wise warnings from friends he insisted on moving the debate onto theological grounds.

Had heliocentricism remained purely scientific, it may well have been that the Catholic Church would have ignored it and perhaps in time with the weight of scientific research in the following years would have accepted the Copernican model of the cosmos.

The Trials

Eventually the church was pushed to act and Galileo appeared before the holy office with the end result being his censure against holding or defending the Copernican theory, Bellarmine issued him with a certificate to this effect.

Galileo instead chose to use a dialogical method in writing (16 years later) the Dialogue on the Two Great World Systems which technically escaped the definition of the Bellarmines censure (though not escape what may have been a forged document in his file that prohibited him from discussing it whatsoever)

The second trial was again the result of Galileo pushing the boundaries of previously good will towards him. In his famous dialogue he ridiculed Pope Urbans (a leading supporter and friend of Galileo) views of astronomy as Simplicio, in effect alienating the one person who could easily have protected him. The controversial file was brought to the attention of a surprised Galileo from the first trial and Galileo by then an old man recanted Copernicanism for a lighter sentence.

Galileo was finally condemned by the Holy Office as suspected of heresy even though Copernicanism itself had never been labelled as heretic.

Galileo was sentenced to keep silent on the subject for the rest of his life, and spent the remainder of his days under house arrest (with relative comfort) in Florence.

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