And Yet it Moves! Part III

Page from Galileo's Book "The Starry Messenger"

Galileo continued to make discoveries about the planets but his writings about heliocentricity were beginning to attract unwanted attention. There are certain verses in the Bible that speak of the Earth remaining still. Galileo, anxious that the Church should endorse his ideas, began to interpret these as speaking in a strictly poetic sense (the verses are taken from books of what are essentially, poems) effectively saying that these verses were merely figures of speech, rather like the way that we continue to speak of sunrises, despite knowing that the sun does not actually rise. St Augustine, the great 5th century theologian of the West had made similar claims about these books so it was a valid interpretation. If Galileo had made these claims in the Middle Ages he would have probably have gotten away with it. But when Galileo wrote, the Counter-Reformation was gaining strength. The Counter-Reformation was the response of the Church to Protestantism and the one thing that they were determined to prevent was individual scriptural interpretation. Even if this had not been ongoing, Galileo was not a theologian and he was told to stick to what he did best and not write about theology when he was unschooled in it.

Cardinal Bellarmine

At this stage Galileo had had an earlier run in with the Inquisition in 1616 but was released after questioning with no ill effects or stain upon his character. The question then had been about the Copernicus himself, who was now long dead. Copernican theory was deemed technically heretical but it was done in such a way that neither the works of Copernicus or Galileo were banned. This was a warning but by 1630 Galileo was on terms of reasonable friendship with the new Pope. The Pope was interested in the heliocentric theory but, with the Church under attack by the Protestants, he was concerned that the Church should only commit to the theory when it was a certainty. The Pope urged Galileo to write a book dealing with the strengths and weaknesses of the different theories and the Pope even put forward some ideas of his own that he thought could contribute to the discussion. Galileo wrote the book.

The book was a great success in terms of publishing but was not well received by the authorities. Galileo had ignored the Tychonic system and completely favoured the Copernican system over the Ptolemaic one. He had also put the ideas of the Pope into the mouth of a character (the book is a fictional conversation between three characters) called Simplicio, who as the name suggests, is consistently portrayed as an idiot. The Pope was furious and turned against Galileo. Now Galileo had to prove his case once and for all and he had to do it before the Inquisition.

Pope Urban VIII

What about the astronomers of Europe? Intellectuals were given quite a bit of free rein in this age of intolerance. If there was a concerted plea from the learned, possibly Galileo would be spared. But Galileo’s skill at making friends had worked here as well. He would make demands for data from other scientists who by and large would share. But Galileo not only did not share his research, but also would often not even answer his letters. He would also occasionally write nasty papers about other people’s work. This was not uncommon unfortunately, but it didn’t help him make friends. Worst of all he had made a declaration to the effect that only he could discover things using a telescope. So when any astronomer made a discovery Galileo would publish a subsequent paper saying that he had seen it first. This was downright intellectual theft and so when Galileo needed friends he found he had none.

In 1633 Galileo was summoned before the Inquisition and he had to prove his case; firstly that he was in no way involved in independent theological reasoning and secondly that there was good proof for the Copernican theory. Galileo had what he believed to be a perfect proof; that the tides were caused by the motion of the earth as it orbited the sun.

Sketches of Imperfections on the Moon

Thus armed, Galileo faced his accusers. What destroyed Galileo was the fact that some of his adversaries were scientists as well. As you may have guessed, Galileo’s theory of the tides was completely incorrect and his accusers were able to point to glaring inconsistencies. The worst by far was that Galileo’s theory predicted the wrong number of tides. With no explanation for the planetary orbits and his theory of tides and motion in tatters, Galileo (who was now an old man) was hemmed in by the power of the Church, abandoned by his friends and scientists and lacking the crucial theories and proofs that would have cleared his name. Facing uncertain consequences he signed a document abandoning Copernicanism and helio-centrism. Galileo spent the rest of his life under house arrest, in relative comfort it is true, but he was nevertheless confined. His works were banned and helio-centrism was confirmed as heretical. The Catholic Church wavered no longer and judged helio-centrism to be contrary to Scripture and as a consequence was left behind by further progress of science. Galileo died in disgrace some years after.

Galileo Galilei

And Yet It Moves: Part I
And Yet It Moves: Part II
And Yet It Moves: Part III
And Yet It Moves: Part IV

And Yet It Moves! Part II

Copernicus

Copernicus had completed most of his calculations and his work was nearly ready to be published. But Copernicus delayed. One might assume, looking backwards at history with our modern notions, that he was concerned about religious persecution by the Catholic authorities but in actual fact, the papacy were very interested in the document and the cardinals wrote to Copernicus urging him to publish. The main religious opposition came from the Protestant side, with both Luther and Melanchthon (Luther's most notable pupil and a crucial figure in the history of Lutheranism) writing against helio-centrism. But Copernicus was well beyond the reach of any Protestant authorities. So why did he not publish?

As usual, we can't really be sure, but it would seem that Copernicus was unhappy with his own ideas. He didn't have any decent proofs of his own work that would stand up to scientific scrutiny, and, as he was not using any advanced scientific equipment, even by the standards of the day, he was unlikely to find any. If he published a work without proof he would have to defend it to the world and he may not have felt equal to the task. His pupil, Rheticus, took it upon himself to publish the book while Copernicus was on his deathbed and the great secret that everyone already knew, was out.

The Copernican Model

Copernicus' work provoked a great deal of debate in Europe, but did not produce a scientific revolution per se. Astronomers, scientists and theologians all agreed that it was an interesting concept but many disliked the idea and most withheld judgement about it. This was not because the intelligentsia of the time were necessarily bound to tradition but because Copernicus' theory was just, well, a theory. It was a theory without proof, a model of how the heavens moved. The problem was that, while it simplified some of the equations and provided a decent model for celestial movements, it suffered from many of the same defects as the Ptolemaic model.

Copernicus had represented the Sun as being in the centre of the Universe around which the planets moved in perfectly circular orbits. From this one could work out the positions in which the planets should appear in the night sky. After all, this was in an age when space exploration was undreamt of and the night sky was all that the astronomers had to go on. And the helio-centric theory was wrong. Interestingly, the word planet derives from the Greek word for “wanderer” due to their unusual tracks in the sky. The planetary positions did not fit at all and Copernicus had to introduce epicycles to try and make it work. But even with these, the orbit of Mars meandered aimlessly and until a theory could be found to reconcile these anomalies, the thinkers of Europe withheld judgement. Copernicus was now passed away and now the challenge had been laid down to either refine and prove the ideas of Ptolemy or Copernicus or come up with a third theory.

Tycho Brahe

A Danish scientist called Tycho Brahe took up the challenge. He came up with a theory where the Earth was at the centre of the Universe and the Sun revolved around the Earth but where the planets revolved around the Sun, rather than the Earth in the Ptolemaic sense. This theory had problems as well but Tycho Brahe made an effort to solve them by setting up a small island full of machines and observation towers to map the sky with unparalleled clarity and prove his theory. There is a modern tendency to ignore Tycho Brahe's work (we now know that he was incorrect) but it should be remembered that Tycho's measurements were probably the finest measurements ever carried out without the aid of telescopes and large volumes of data were collected with the help of his assistant, Johannes Kepler. But still the theory didn't quite work. Tycho Brahe died hoping that his assistant would continue to work on perfecting the Tychonic theory but it was not to be. Kepler became obsessed with the mystical notion of perfect shapes (circles, triangles, etc.) that, if their radii and lengths of sides held a certain proportion, could give the right figures for the orbits of the planets in a Copernican system. This sounds like a pretty silly notion to us, and it is actually nonsense, but it was to have important consequences.

Tycho Brahe's island

The political situation of the time was changing. The rapid spread of Lutheranism had pretty much stopped and the second wave of Protestantism (Calvinism) had begun. The Catholic Church had reasserted doctrinal points in the Council of Trent and had begun to combat the spread of Protestantism effectively. The Inquisition in Italy and Spain and the newly founded order of the Jesuits were crucial in this retrenchment of Catholicism. The old haphazard tolerance of the Middle Ages and the Renaissance disappeared as the champions of Reformation and Counter-Reformation kept watch for any deviation from the doctrines of their particular church.

There are certain passages in the Bible that seem to suggest that the Earth remains in place. When Copernicus' work was first published no one in the Catholic Church objected to it, but after a few years minor clerics began to question whether Copernicus could be reconciled with Scripture. The Protestants, who had no central authority anyway, became more amenable to the doctrine but it wasn't considered important enough to really merit discussion from the pulpit. The Catholic Church made no official decision regarding Copernicus and whether his text was heretical but the Inquisition was examining any belief that deviated from the norm and it was possible that helio-centrism might be a cover for heresy. This uneasy situation, where helio-centrism was tolerated but could attract suspicion, lasted for a number of years.

Kepler's Initial Vision of the Universe

Meanwhile, an Italian scientist by the name of Galileo Galilei (finally, we get to Galileo) heard of a Dutch invention, which we now refer to as the telescope. Galileo is often credited with the invention of the telescope but in fact he merely refined it. However, he was probably the first person to use it to look at the sky. Galileo discovered the larger moons of Jupiter fairly quickly and became enamoured of the heliocentric theory. If the planets had moons then possibly the earth, which had a moon, was also a planet. At the time philosophers believed (from Aristotle) that the celestial bodies were perfect and almost of a different order of being from earthly objects. Galileo discovered the imperfections on the Moon's surface and speculated that the heavenly objects were in fact of the same order as the earthly ones.

These were important discoveries but still very far from proofs. Galileo had become a strident advocate of Copernican theory. Unfortunately this confidence in his ideas was to bring the Church authorities against Galileo and trigger possibly the most famous confrontation of science and faith in history.

And Yet It Moves: Part I
And Yet It Moves: Part II
And Yet It Moves: Part III
And Yet It Moves: Part IV