He never did the fandango

Finished Galileo's Daughter over the weekend. A fascinating read that confirms some of the legends, sweeps away others and replaces them with facts that are ten times more interesting. Rather than just be a straight biography it chronicles Galileo's life through letters from his daughter, a highly intelligent, capable woman stuck in a convent under the nunly name of Maria Celeste. Sadly we only have her letters to him. His letters to her were almost certainly destroyed by the nuns when she died (a few years before he did) in case they were tainted by association with an infamous heretic. Even so, we don't just get Galileo's life but we get a pretty good cross-section of life in Renaissance Italy generally.

The conventional view is that stuck-in-the-mud corrupt, totalitarian church says the earth is stationary, Galileo says it orbits the sun, Galileo is tortured by Inquisition into renouncing his views.

Well ...

Galileo lived from 1564-1642, which in English terms means he was born the same year as Shakespeare, lived through the reigns of Elizabeth, James I and Charles I, and died in the early years of the English Civil War. I think I'd rather have spent that period in Italy, where the weather was better and most of the down sides to life (like the occasional outbreak of the Black Death, and you really didn't want to drink the water) would have applied anywhere. Meanwhile they already had a lot of the science and maths that build up a civilisation and make life bearable, and they seem to have had a basic knowledge of hygiene and medicine; Maria Celeste was forever sending her dad little medicines for his various ailments.

Contrary to the popular view, the church wasn't a black-clad evil empire forever poised to oppress and torment the helpless. Galileo had a lot of good friends, even among churchmen, who braved the wrath of the Pope. After his disgrace he was taken in and helped by the Archbishop of Siena, whom even the Pope couldn't just silence, but several rank-and-file Fathers also came to his support.

Not that society was by any means perfect. Galileo never got round to marrying the mother of his three children because the class difference made it unthinkable, which made them unmarriageable. He could pull strings with his aristocratic friends to have his son officially legitimised, but for his two daughters there was no choice but the convent.

Before his fall Galileo was the darling of the establishment, which was quite strongly pro-science and pro-mathematics. He was a highly respected mathematician courted by church and aristocracy – who were mostly Medicis and who behaved very honourably towards him; not a trait we've become accustomed to identifying with that particular family. In his mid-thirties he invented a device which "could compute compound interest or monetary exchange rates, extract square roots for arranging armies on the battlefield, and determine the proper charge for any size of cannon." It made him a fortune.

And Galileo was a devout Catholic, horrified at the very thought of going up against his beloved church. His fame led him to become quite pally with the Cardinal Maffeo Barberini, who encouraged him in his writing.

But I don't think either party realised until too late that what drew them together wasn't a love of science, it was their love of Catholicism. Galileo held that there were things even scientists wouldn't figure out, and he stated it very poetically, which Barberini loved. But Galileo's God also acted logically and consistently; Barberini's God could do what he liked. Galileo rightly pointed out how astonishingly complex it would be to have the sun revolve around the earth and the other planets around the sun. Barberini's attitude was, yes, isn't it? God's so clever. Then Galileo realised that the sun itself seemed to revolve at different angles (i.e. the sun revolves around its tilted axis, and so does Earth, so to us the sun seems to wobble), making the whole system an order of magnitude more complex. Or, from Barberini's point of view, making God even cleverer.

Galileo believed the Bible was about the relationship between God and Man, and how to get to heaven. Barberini believed the scriptures are there to micro-manage our day to day existence and are just as valid as scientific works as they are on matters of faith and morals; and anyway, sunshine, what are you doing interpreting the Bible yourself? That's our job. He would have got on very well with a lot of Creation scientists today, except that they tend to be Protestant and the Catholic church nowadays has no problem with the ancient earth thing.

And Barberini went on to become Pope.

The work that got Galileo into trouble actually started out as a treatise on tides, and if he had stuck to it then nowadays no one would remember it because he got the causes of tides spectacularly wrong. But no, Dialogue Concerning the Two Chief World Systems went on to discuss Copernicus, who held that the earth went round the sun. Hypothetically. Earlier in his career, Galileo had been told not to 'hold or defend' the Copernican view; he was still allowed to discuss it hypothetically. Galileo went through all the approved steps of seeking church permission and censorship to have the book published and finally had a bit of paper from the church saying it was acceptable. By the time it was published, Barberini had become Pope Urban VIII.

As Popes go he was, by all accounts, a pretty rubbish one, beleaguered with critics. He got Rome caught up in the Thirty Years War, he ran up massive debts and he badly over-reached himself. So he was already in a pretty bad mood when the Dialogue came out, and it seemed to push Copernicus way too heavily. Here was an easy target to restore papal authority, so the matter was referred to the Inquisition. Galileo never had a chance.

He wasn't tortured, just interrogated, but he knew where he stood. Once it was obvious that even his old friend the Pope was against him, Galileo knew he had no choice but to sign a formal retraction and repentance. The Dialogue was banned – in Italy – for the next 200 years. If they had had eBay, bootleg copies would have been popping up almost immediately.

The sentence ended Galileo's public career in Italy, though the Pope continued to be irritated by the number of mathematicians and scientists who sought him out for private consultation. The final and finest work of this devout Catholic, Two New Sciences, had to be published in the Protestant Netherlands.

And this was the book that mattered. The book that gives him a reason to be famous. Face it; yes, it is important how the planets work, but we could get by to a great extent without knowing. And other people, with telescopes, safely outside the range of Rome, would have worked it out eventually. But Two New Sciences dealt with materials and objects in motion, stuff that isn't immediately obvious to the naked eye but must be worked out. It was a work of genius.

Imagine an arbitrary period of time. Let's say it's the time it takes for you to count to ten divided by the number of times the cock crows – it doesn't matter. Just be consistent. Call it anything you want. Call it the oobamasquif.

Now measure the speed of a falling object and time it. After two oobamasquifs, its speed will be its speed at one oobamasquif, squared. After three oobamasquifs its speed will be its speed at two oobamasquifs, squared. And so on. However you measure it – seconds, hours, minutes, oobamasquifs – acceleration increases by squares. How astonishing is that?

And Galileo worked this out, without benefit of clocks or any kind of mechanical aid, and in doing so laid down the foundation for modern science. Newton, born the year Galileo died, couldn't have done his work on gravity without Galileo backing him up. All this from a book written in his seventies, after his public and national disgrace.

As an author in his forties and yet to be famous, I find that quite encouraging.