During a conference-related sojourn in Florence a while ago, I had the opportunity to visit the Museo Galileo to pay homage to one of my intellectual heroes. As well as having a giftshop that I haunted like a highly corporeal poltergeist, it was full of remarkable scientific artifacts. It had memorabilia of the great man himself from the macabre (one of his fingers with tendons intact inside a gilded glass case) to the truly sublime (first editions of The Starry Messenger and Dialogue , as well as the lens that first showed him the moons of Jupiter). There were practical demonstrations of his work on the motion of falling bodies, clock mechanisms and ballistics which kids and adults alike were playing with. The whole building was a temple dedicated to early scientists’ struggles with technology and the abstract mathematical laws that describe our universe.
I eventually departed having whittled my purchases down to just three books, a t-shirt and some fridge magnets. One of the books was called Galileo:Antichrist which despite the thoroughly sensationalist title was a serious scholarly attempt to look behind the obvious motives for his trial and punishment by the Church to some of the contemporary nuances. I highly recommend it, if you’re a Galileo freak and historical conspiracy theory enthusiast like me.
My reading and looking around did get me thinking though. I came up with a few reasons why the average citizen needs to know and appreciate Galileo now as much as ever.
He got rid of Aristotle from science
Before Galileo, science (known then as natural philosophy) was based almost entirely on the writings of Aristotle. St Thomas Aquinas enshrined a huge amount of Aristotle’s teachings about the natural world as Church-approved dogma without any empirical basis. Until the Renaissance, virtually nobody in Europe or anywhere else apart from Arabic geniuses like Ibn Sina and Ibn Rushd advanced science by paying attention to the real world. They just looked up what Aristotle had to say and left it at that, even if what they observed was at odds with what they read.
Galileo did more than anyone else to rid natural philosophy of its reliance on the authority of Aristotle, replacing it with an empirical and mathematical method. Deciding scientific knowledge by scholarly argument rather than doing experiments seems bizarre to us now. Galileo showed again and again that mathematical models could yield results that were reproducible by anyone else and disproved Aristotle’s observations. Eventually, the successes of the new way of doing natural philosophy were too overwhelming to ignore. The Aristotelians slunk off to find other occupations. Galileo showed irrefutably that you couldn’t do science by magisterial authority alone. Your results had to stand up to scrutiny in the real world.
He was not the prototype of a misunderstood lone genius
Galileo conducted a wide-ranging correspondence with other scientists of the day. When he published the Starry Messenger to announce his discovery of the moons of Jupiter with his new telescope, he not only sent out copies of his books to his colleagues, but also sent them better telescopes than the ones they had! Having his peers review and replicate his revolutionary findings was very important to Galileo. The message for current-day pseudoscientists and cranks who cite him as a misunderstood genius is to look elsewhere for a hero. As Robert Park commented,
It is not enough to wear the mantle of Galileo: that you be persecuted by an unkind establishment. You must also be right.
Galileo was not only right in his revolutionary findings about the solar system and moving bodies, but he took pains to help others understand how he was right. He was a practising believer in developing a scientific consensus. His disastrous run-in with the Catholic Church was about personality politics and religious dogma. He was revered in his lifetime by every natural philosopher of note, although some of ones he personally insulted were somewhat grudging in their admiration.
He could, of course, also be spectacularly wrong. Nobody remembers his views on comets and the causes of tides, which were two of the biggest contemporary scientific controversies he weighed into. It should also be pointed out that these were the two most prominent examples where Galileo was being particularly stubborn in holding out against the prevailing tide of opinion.
He was genuinely interdisciplinary
In an era where the public image of scientists is still that of poorly-dressed, socially inept nerds, it helps to have a role model like Galileo. He was relentless in his search for practical applications of his work. A Renaissance Man if you will. He had a truly comprehensive vision of the place of science in understanding nature for its own sake, as well as for any practical applications it might have. In a modern Australian university, he would be both a blue-sky curiosity-driven researcher (beloved of academic types) but also one who had generates heaps of commercial spin-offs and industry partnerships (beloved of administrators and politicians).
While his astronomical work may seem like it had no practical applications, it led him to develop a way of measuring longitude at sea that was not surpassed until more than 150 years later. He translated his knowledge of the abstract mathematical minutiae of optics into building much better telescopes than anyone else had. He extended this theory to conceive and design the microscope as well. He also used his knowledge of motion to build improved artillery sights, improving accuracy by calculating the parabolic arc of the shot correctly. He built a military compass for artillery operators to calculate the angle of their gun and amount of powder to land their shot more safely (for the bombardiers!). In the final year of his life, having gone totally blind, Galileo conceived and dictated the design for a clock escapement which was very similar to the one used by Huygens to construct the first pendulum clock a couple of decades later.
He stood up for the philosophy of science
Despite using maths that is now taught in high school and equipment that would embarrass a 21st century toy shop owner, Galileo utterly changed the way his contemporaries saw themselves in the universe. Educated citizens of his time had a sophisticated explanation of the world and the heavens, but it was based on dogma and supposition to a degree that is very hard to comprehend today. By making arguments that were based on reasoning, mathematics and experimental verification, he was consistently and obviously successful with many of his predictions. This opened his contemporaries’ eyes to the extraordinary possibilities on offer with knowledge gained by the scientific method.
Observing that Venus had phases like the moon, and having plotted the orbits of the Galilean satellites meticulously, he could join the dots conceptually, and followed the chain of reasoning to the end. The results were not what he was originally looking to discover, but he just couldn’t turn his back on his data. Earth was demoted from the fixed centre of the medieval universe to just another planet orbiting the sun. He strenuously sought ways to avoid provoking the Church (he was a devout believer right to the end) but he could not stop progressing and disseminating his research, despite those who told him it was safer to pull his head in.
He insisted that dependable, reproducible scientific results should trump religious dogma or non-empirical philosophical ideas any day of the week. He paid a price for his abrasiveness, but he should not be remembered just for the events that blighted his later years. His persecution and house arrest by the Vatican were not inevitable, but threw into sharp focus the clash of his era between a recognisably modern science-based worldview and the medieval superstition of authoritarian belief systems. Somebody had to be the first to point out the Emperor’s new clothes.
Looking at those artifacts from this distance in time, you can still feel the passion and excitement that his extraordinary life generated. Galileo was a great but flawed individual, and I have to say even now I’m not sure if I’d enjoy having him over to dinner. I am however eternally grateful for the effect his life’s work had on the philosophy of science. Development of the Enlightenment values that underpin our society would not have been possible without the seismic burst of rationalism that Galileo unleashed from his villa in Northern Italy 500 years ago.