The Galileo legend is of a spiteful, outdated Church. The reality is more complex

The trial of Galileo

On Trial for Reason
By Maurice A Finocchiaro
OUP, 289pp, £25/$32.95

June 22, 1633, was not the happiest of days for Galileo Galilei, though it might have been a good deal worse. His musings on the workings of the cosmos brought down the charge of “vehement suspicion of heresy” on his head. But the Inquisition did not accuse him of what the canon lawyers referred to as “formal heresy”. It was an important distinction.

The “formal” heretic was perceived as repeatedly, malevolently spreading noxious beliefs; the “suspected” heretic was the chap who made offensive statements once in a while but didn’t really want to bring Christendom to its knees.

Still, the consequences for Galileo were onerous enough. He was obliged to say that he renounced the opinions “rightly” attributed to him. He would spend the remainder of his life under house arrest. Perhaps most importantly, the book which had landed him in so much trouble, the Dialogue of the Two Chief World Systems (1632), was banned. The Church had put its foot down.

Galileo had been warned, back in the 1610s, to avoid overly zealous approval of Copernican ideas. They could be deployed as an abstract hypothesis – helping to account for and calculate the movements of heavenly bodies – but Galileo seemed to have grown increasingly certain that heliocentric theories reflected a physical reality. Worse still, his writings were seen (rightly or wrongly) as undermining the notion that Scripture was always a reliable authority when it came to grasping the workings of the natural world.

And so a legend was born: the spiteful, obscurantist Church trampling on the plucky Paduan; faith joining battle against science. But it was not, as Marco Finocchiaro’s spirited book reminds us, quite that straightforward. Take Galileo’s intellectual trajectory, for example. He was clearly attracted by Copernican ideas from early in his career but, rather against character, he proceeded with a good deal of caution.

Even the fateful 1632 book looked at arguments on both sides of the debate – though only a dimwit could have doubted that, by this time, Galileo was utterly convinced that heliocentrism was the most probable theory – “true” to all intents and purposes.

Nor should we imagine that Galileo’s opponents were intellectual simpletons clinging to outmoded nostrums. The earth revolves on its axis and orbits the sun, you say? Very well, prove it, came the reply. Galileo couldn’t and no one would be able to do so for a century and more: the proofs offered by annual stellar parallax or the genius of Léon Foucault’s pendulum would have to wait.

Some even now would readily admit that Galileo was right, but they’d suggest that the specifics of his methodology left a lot to be desired. At the very least, any assertion that the scales should inevitably have fallen from the eyes of anyone with an ounce of nous in 1633 is a little unfair.

Finocchiaro also helps us to understand why the whole Galileo affair got out of hand. Galileo had no overwhelming desire to court theological controversy. He was, of course, crystal clear on the primary role of observation in solving the universe’s riddles, and if some biblical text or other posed a problem then it would have to be re-examined. But, in the end, this only suggested that human interpretation of Scripture (especially of the literal variety) could be wide of the mark. It did not, in and of itself, represent a frontal assault against the truth claims of the Bible. Even Augustine had argued that when natural scientists came up with a theory that looked highly probable, then it was time for theologians to look afresh at any hermeneutical flies in the ointment.

The issues at stake were momentous, but why did it all become so nasty? Well, Catholic setbacks in the Thirty Years War had put Rome in a grumpy, defensive mood and the papacy was also keen to bring Tuscany (the home of so many participants in the controversy) down a peg or two.

Everyone knew that the cosmos had changed: telescopes had revealed sunspots, a pockmarked lunar surface and satellites whizzing around Jupiter. So images of a perfect, flawless, unchanging universe beyond the earth would have to be ditched. That, in the end, was all Galileo ever suggested, and it’s a shame that the turbulent dynastic and ecclesiastical politics of the 1630s fanned the flames of a squabble that might have been handled a little more delicately.

Copernicus had better timing than Galileo. When the first copies of his groundbreaking 1540s treatise arrived from the printer he was already on his deathbed. He dodged the backlash.

Not so Galileo: he was a combative, litigious man (try stealing one of his ideas) with a bad habit of insulting his enemies. But he made a decent point in the midst of his tribulations: “We must not desire that nature should accommodate herself to what seems better arranged and ordered to us.”