Pope Benedict in his Epiphany homily mentions that this year 2009 has been dedicated in a special way to astronomy to mark the fourth centenary of Galileo’s first observations with the telescope. He goes on to say:
... there is a special concept of the cosmos in Christianity which found its loftiest expression in medieval philosophy and theology. In our day too, it shows interesting signs of a new flourishing, thanks to the enthusiasm and faith of many scientists who following in Galileo's footsteps renounce neither reason nor faith; instead they develop both in their reciprocal fruitfulness.
Galileo, having developed a more powerful telescope than others of his day, made important new observations about the moon of Jupiter, the phases of Venus, and spots on the sun that undermined Ptolemy and were consistent with Copernican view of the solar system - with the Sun at its centre.
It has been alleged, repeatedly, especially by contemporary proponents of atheism, that this landed Galileo in hot water with the Vatican, which was hell-bent on upholding the ancient belief that all celestial bodies revolve around the Earth.
The historical record is not quite that simple.
Galileo took his observation to the Jesuits who were among the leading astronomers of the day and they agreed with him that his sightings had strengthened the case for heliocentrism. The Jesuits told him that the church was divided, but the question was still open, and they did not think that Galileo had clinched the case.
When Galileo was reported to the Inquisition, Cardinal Bellarmine met with him. This was not a normal Inquisitorial procedure, but Galileo came to Rome in 1616 as a celebrity with great fanfare, where he stayed at the Medici Villa, met with the pope more than once, and attended receptions given by various bishops and cardinals.
Bellarmine wrote: “While experience tells us plainly that the earth is standing still if there were a real proof that the sun is in the centre of the universe ... and that the sun does not go round the earth but the earth around the sun, then we should proceed with great circumspection in explaining certain passages of scripture which appear to teach the contrary, and rather admit that we did not understand them than declare an opinion to be false which is proved to be true. But this is not a thing to be done in haste, and as for myself, I shall not believe that there are such proofs until they are shown to me.”
Given the inconclusive evidence and the sensitivities involved, Bellarmine determined that Galileo should not teach or promote heliocentrism. Galileo, a practising Catholic who wanted to maintain his good standing with the church, agreed. Bellarmine issued the injunction and made a record of the proceeding that went into the church files.
For several years Galileo kept his word but then Cardinal Maffeo Barberini was named Pope Urban VIII. Barberini was a scientific “progressive,” having fought to prevent Copernicus’s work from being placed on the index of forbidden books. He was also a fan of Galileo. Urban VIII held that while science can make useful measurements and predictions about the universe, it cannot claim to have actual knowledge of reality known only to God.
Galileo was confident now that he could openly preach heliocentrism and in 1632 he published his Dialogue Concerning the Two Chief World Systems. This created a threefold problematic.
First, his so-called demonstration of the truth of heliocentrism was faulty. One of Galileo’s main arguments was that the rapid motion of the earth around the sun was responsible for the ocean tides. Galileo also assumed that planets move in circular paths, even though Kepler had shown that the planetary orbits are elliptical. Galileo contended that Kepler was wrong.
Secondly, Galileo embarrassed the pope by constructing his dialogue between two figures, one representing himself and the other representing the pope, who was given the name “Simplicio.” Of course, the foolish claims by Simplicio were refuted by the character speaking for Galileo.
Thirdly, Galileo’s writings were not confined to scientific issues; he argued that the Bible was largely allegorical and required constant reinterpretation to excavate its true meaning. The Jesuits had warned him not to venture into this territory as Scriptural interpretation was the church’s area but he ignored the advice and was once again reported to the Inquisition.
In 1633 Galileo returned to Rome, where again he was treated with respect. However, during the investigation, someone found Bellarmine’s notes in the file. Furthermore, Galileo had not told anyone about his previous agreement. Now Galileo was viewed as having deceived the church as well as having failed to live up to his agreements. Incredibly, for some strange reason, Galileo maintained that his Dialogue did not constitute a defence of heliocentrism.
Galileo was never charged with heresy, and never placed in a dungeon or tortured in any way. Technically he was under house arrest in his villa in Florence but enjoyed considerable freedom. The church also permitted him to continue his scientific work on matters unrelated to heliocentrism. He died of natural causes in 1642.
It was during subsequent decades that newer and stronger evidence for heliocentrism emerged, and scientific opinion, divided in Galileo’s time, became the consensus that we share today.
Alfred North Whitehead, a noted historian of science, concluded: “that the worst that happened to men of science was that Galileo suffered an honourable detention and a mild reproof, before dying peacefully in his bed.” The traditional picture of Galileo as a martyr to intellectual freedom and a victim of the church’s opposition to science is little more than a caricature.
☩ Frederick Henry