Thursday, 27 October 2011

And Yet it Moves! Part IV

Galileo before the Inquisition
This blog post is the fourth and final post in a series about the Galileo Affair. Click here for the first post, here for the second post and here for the third.

The whole affair has an air of tragedy about it, with the protagonists cursed by their own abilities and destroyed by their own inherent faults. The Church was initially agreeable to helio-centrism (which is true, just in case people were wondering) but the thought of being questioned on theology terrified them and to be faced with an arrogant layman who told them what to believe caused the clerics to strike back to protect the status quo. Galileo was a victim of his own ego. He repeatedly alienated potential allies because they showed signs of ability and he refused to admit the possibility that he was wrong to champion Copernicus’ theory.

Johannes Kepler
            What turns the tragedy into farce is that, while both sides were wrong, the answer had already been discovered if either side in the trial had bothered to read it. Johannes Kepler, whom we came across earlier, had been obsessing about perfect shapes affecting the planets which had by a convoluted process, allowed him to discover the laws of planetary motion. The flaw in Copernicus’ theory was that Copernicus, like the medieval philosophers, had simply assumed that all planetary motions were circular. By introducing elliptical orbits Kepler had saved the day and completed the revolution (if you’ll pardon the pun) that Copernicus had started. Kepler had helped Galileo with his work but when he sent a copy of his own book to Galileo, hoping for an endorsement from the great astronomer, Galileo ignored it. Kepler died in 1630 but his theories were already receiving tentative confirmation by 1631.The great showdown between Galileo and the Inquisition was not until 1633 and news travelled fast between scientists.

The church astronomers and Galileo should have been aware of Kepler’s ideas and discoveries (Galileo had actually had the book sent to him by the author). Another damning mark against Galileo is that Kepler had also published a theory of the tides, which Galileo viewed as being pivotal to helio-centrism. Kepler had an alternative idea, albeit a crazy one, that the tides were caused by the Moon’s movement acting at a distance. Galileo laughed at it as a “useless fiction.” Kepler was right. Galileo was wrong.

            The Galileo Affair was a clash of science against religion. It was also a clash of bad science against well, bad science. But it was mainly a clash of egos. Galileo was a great man. His work on falling bodies paved the way for Newton and was his greatest achievement but he was active in making discoveries in many branches of science. But, by refusing to admit that he could be wrong he drew the anger of the authorities on himself. The Catholic Church behaved poorly as well, and its dogged insistence on treating anything associated with opposition as heresy hurled it from being at the cutting edge of science to being (from a scientific perspective) hundreds of years behind the rest of Europe.

            And who was the real hero of the affair? Galileo was not the infallible man of science. There’s no real evidence that he ever muttered “Eppur si muove!” (And Yet It Moves!) and his conduct betrayed all too human failings. He was a genius and we can forgive genius a lot. But for a truly extraordinary man of science, one whom we should take as a role model, I believe that Kepler is the real hero of the tale.

The Old Geocentric Model: What we have left behind


Postscript: It should be noted that some people have told this tale with slight variations, some favouring Galileo more, others favouring the Church. I am roughly retelling, in a far inferior form, the historical narrative laid out by Arthur Koestler in his excellent book Sleepwalkers. If you want to read more about the events, times and people involved in the birth of the scientific revolution I would highly recommend it.