“I do not feel obliged to believe that the same God who has endowed us with senses, reason, and intellect has intended us to forgo their use and by some other means to give us knowledge which we can attain by them.”–Galileo Galilei, 1615
Despite the paradigm-shifting idea of our #28, Nicolaus Copernicus, for nearly a century afterward his heliocentric theory twisted in the solar wind. It took another man to confirm Copernicus’s daring theory. That alone would make this other man an all-time great contributor to Western science, but he gifted us so much more than merely confirming someone else’s idea. He had a series of inventions, discoveries, and theories that helped modernize science. His accomplishments in mechanics were without precedent. His telescope observed what was once unobservable. Perhaps most importantly, he embodied, furthered, and inspired a growing sentiment that truth is a slave to science and facts, not authority and dogma.
This man was Galileo Galilei, and he’s the 12th most influential person in Western history.
Galileo was born in 1564 Pisa, Italy — 21 years after Nicolaus Copernicus published his major work on heliocentrism. Galileo benefitted from an Italy that had been experiencing renewed intellectualism for quite some time. It was in Italy that the Renaissance began more than a century earlier, and by the time of Galileo’s birth, the printing press had aided literacy levels across western Europe. The Scientific Revolution followed on the heels of Copernicus, and Galileo took full advantage.
Only in his teens, he identified the tautochronic curve that explains why the pendulum behaves as it does. This discovery laid the groundwork for Christian Huygens to create the world’s first pendulum clock, which became the most accurate method of keeping time into the twentieth century. The precocious Galileo also invented the thermoscope, a forerunner to the thermometer. At just 22, he published a book on hydrostatic balance, giving him his first bit of fame.
He attended medical school but, for financial reasons, he had to drop out and work as a tutor. Nevertheless, he eventually became chair of the mathematics department at the University of Pisa. A few years later, he moved to the University of Padua to teach geometry, math, and astronomy. It was a promising start. He taught at Padua for nearly 20 years, and it’s there where he turned from reasonably well-known Galileo Galilei to Galileo. Like the great Italian artists of his age, he became so talented and renowned that soon just his first name sufficed.
What isn’t sufficient is a pure chronology of Galileo’s accomplishments. Throughout his career, from teaching to house arrest, he made accomplishments across several fields. There were no neat phases of discoveries like those had by, say, Charles Darwin (#15). Thus, we will organize his career by category.
We’ll start with mechanics, a branch of physics which studies motion, forces, and friction. The field had been around since, as usual, the ancient Greeks, with Archimedes and Aristotle (#30) among their foremost experts. Aristotle — also as usual — was, on the topics of mechanics and gravity, sometimes right and sometimes wrong. He felt objects fall because their natural place is at the center of the earth, which is in fact toward where objects fall. Unfortunately, he also theorized that heavier objects fell faster than lighter ones. Observing a light feather fall slower than a rock suggests such a conclusion.
Galileo tested the theory. He found that balls of similar substance but different mass fell at the same rate. Through experimentation, he determined that a feather falls slower than a rock not because of the contrasting weight but because of the extra friction caused by the displacement of Earth’s atmosphere on the flatter object. (The most famous confirmation of Galileo’s theory was done by Apollo 15 astronaut Dave Scott, who, while standing on the moon, dropped a hammer and feather simultaneously and watched them hit the lunar surface at the same time.) Galileo built on this foundation a mathematical formula that showed the rate of acceleration for falling objects on Earth. Tying math to physics, he essentially laid the groundwork for later studies of inertia. These mechanical discoveries provided a firm launching point for Isaac Newton’s further modernization of the field.
Though his contributions to mechanics and physics are almost without rival, what Galileo is most famous for are his astronomical accomplishments. While conventional wisdom is wrong about his supposed invention of the telescope, his astronomical résumé is far broader than just one invention.
In the early 1600s, despite Copernicus’s elegant heliocentric model of the solar system having debuted more than a half-century earlier, skeptics remained. Indeed, there was an ongoing divide among astronomers; some favored the Copernican model while others clung to the traditional Ptolemaic premise adopted by the Catholic Church, which put the earth at the universe’s center. Even Tycho Brahe, a leading post-Copernican astronomer, favored geocentrism, though his Tychonic system did make some allowances for Copernicus’s less controversial ideas. Brahe’s position helped him avoid the fate of heliocentrist Giordano Bruno, who was burned at the stake by the Catholic Inquisition in 1600. This heated astronomical climate awaited Galileo Galilei.
Like Bruno, Galileo knew Copernicus was right, and he set out to prove it. Early in the seventeenth century, he received word about a new invention created by the German-Dutch spectacle-maker Hans Lippershey. In 1608, Lippershey used his knowledge of lenses to make a refracting telescope, which used lenses, an eye piece, and angular strategies to bend light, allowing in more of it. More light could clarify and magnify a desired object, and Lippershey’s rudimentary design could make something appear about three times bigger. Galileo, though he never saw a telescope in person nor even designs of one, heard a basic description of it, checked the information against his brain’s enormous database, realized it could work, and built one of his own. A better one.
With his improved telescope he could magnify objects thirty times, and he immediately pointed it to the once unknowable heavens and transformed astronomy in numerous ways:
- It was assumed that the moon, like all the heavenly spheres, was perfectly smooth. Galileo observed craters and mountains. He inferred, accurately, that all celestial objects had blemishes of their own.
- Though Jupiter had been observed since the ancient world, what Galileo was the first to discover was satellites orbiting around it — the Jovian System. In other words, a planet other than the Earth had stuff orbiting it. It was another brick in Copernicus’s “we’re not that important” wall.
- Pointing his telescope at the sun, Galileo observed sunspots. Though the Chinese first discovered them in 800 BC, as Westerners did five hundred years later, no one had seen or sketched them as clearly as Galileo had. It was another argument against the perfect spheres in our sky.
- Galileo also discovered that Venus, like the moon, has phases (crescent/quarter/half, waxing/waning, etc.). This was a monumental step in confirming Copernicus’s theory, as Venusian phases require certain angles of sunlight that a geocentric model does not allow.
- The observable hub of the Milky Way galaxy was assumed to be, just as it looks to us, a big, milky cloud. Galileo discovered it was not a cloud, but a huge cluster of stars. (We now know it numbers in the billions.)
Galileo not only confirmed Copernicus’s heliocentric theory, but he allowed the likes of Johannes Kepler to more accurately plot out the planets’ orbits, Isaac Newton to explain how it was happening, and Albert Einstein to explain why. It was such a colossal step forward for the observable universe that some people didn’t even believe what they were seeing in the telescope, electing to instead remain skeptical of Galileo’s “sorcery.”
Ever the watchdog on sorcery, it was time for the Catholic Church to guard its territory. Protective of geocentrism and its right to teach us about the heavens, the Church had some suggestions about exactly where the astronomer could stick his telescope. In 1616, under the leadership of Pope Paul V, heliocentrism was deemed officially heretical, and Galileo was instructed “henceforth not to hold, teach, or defend it in any way.”
A few years later, a confusing stretch of papal leadership got Galileo into some trouble. In 1623, Pope Urban VIII took a shine to Galileo and encouraged his studies by lifting Pope Paul’s ban. A grateful Galileo resumed his observations and collected them into his largest work, 1632’s “Dialogue Concerning the Two Chief World Systems.” In it, he sums up much of his observations and shows the superiority of the newer heliocentric model. The following year, almost as if a trap were set, the Catholic Inquisition responded with a formal condemnation and trial, charging him with violating the initial 1616 decree. Dialogue was placed on the Church’s Index of Prohibited Books.
Galileo’s popularity, combined with a sheepish Pope Urban, limited his punishment to a public retraction and house arrest for his remaining days. At nearly 70, he didn’t have the strength to resist. Old, tired, and losing his vision after years of repeatedly pointing a telescope at the brightest object in the solar system, he accepted his sentence. Blind and condemned, his final years were mostly spent dictating “Two New Sciences,” which summarized his 30 years of studying physics.
Though keen and curious until the end, his body gradually failed him. In 1642, it gave up. His long, fascinating life came to an end at the age of 77.
I must admit, despite his ranking near the middle of this Top 30, Galileo probably put together a top five résumé. Save only Newton, he’s probably the most diversely accomplished scientist on this list, and I’ve clearly evaluated scientists as enormously important in Western development. Why, then, have I ranked him just 12th?
It’s because Galileo, despite his amazing career, falls comparatively short in the key requirement for this list’s historical figures: influence. Don’t get me wrong – he’s hugely influential. Still, he’s less influential, I think, than the 11 names still to come.
The broadest arguments for his influence comes from his several historical titles, including the “founder of modern astronomy” and the several mentioned by his Wikipedia entry: “the ‘father of modern physics,’ the ‘father of scientific method,’ and even the ‘father of science.’” It’s an impressive array.
With each of them, however, I must disagree. The “father of modern astronomy” label is surely worn by Copernicus. Switching from geocentrism to heliocentrism is the clearest demarcation in astronomical history. There is no more important turning point in advancing the field. Galileo should be commended for confirming and expanding on it, but Copernicus was its founder. Indeed, google the phrase “founder of modern astronomy,” and it’s Copernicus that dominates the results. Though Copernicus doesn’t have the breadth of Galileo’s contributions, hence the former’s lower ranking, his hallmark accomplishment pushes back against Galileo’s astronomical paternity.
Similarly, “founder of physics” is much more appropriate for Isaac Newton, whose hallmark laws of motion and gravity formalized the field. Meanwhile, “father of modern physics” turns up Einstein. For those reasons and more, we’ll see they’re ranked higher than Galileo.
The last two monikers we can lump together: the “father of the scientific method” and the “father of science.” In both cases, there are more appropriate choices. The father of the scientific method in the West, as discussed in my #30 entry, is Aristotle. (Or, perhaps, Thales before him.) Admittedly, one might reasonably choose to dismiss Aristotle due to his many errors or the fact that science was later lost to the West during the Dark Ages; these opponents might elect to relegate him to “grandfather” status. Even granting that, the modern scientific method is more often attributed to Galileo’s contemporary, Sir Francis Bacon (1561-1626). Furthermore, if we identify the turning point of modern science, we again return to Copernicus and, to a lesser extent, anatomist Andreus Vesalius. Two decades before Galileo was born, they each published a seminal work. Copernicus’s “On the Revolutions of the Heavenly Spheres” transformed astronomy. One month later (amazing, if you think about it), Vesalius’s “On the Fabric of the Human Body” laid the foundation of modern anatomy. Thus, the year of those works’ publication — 1543 — traditionally marks the beginning of the Scientific Revolution, a period that allowed Galileo to flourish.
Nonetheless, Galileo became the embodiment of this modernizing movement, and he advanced it unprecedented ways. He tied science to mathematics. His meticulous quantitative measurements became the standard for all scientists to come after him. His relentless empiricism made him the foremost scientist of his century.
Moreover, Galileo’s successes were symbolic of a cornerstone in modern science. His struggle against the Church embodied the argument that truth comes from experience, experiments, and the facts — not dogma. He showed us authority and knowledge are not interchangeable. Though the Inquisitors silenced him in 1633, his discoveries, works, and ideas outlived them. For centuries, he has stood as an inspiration for free thinkers wrestling against ignorant authority.
For that, he has my gratitude, and he also earns my spot as the 12th most influential figure in Western history.
Before reading any further, I recommend first looking over, if you haven’t already, my entry on Copernicus (#28). It’s a sort of prequel to Galileo’s story. Isaac Newton will later finish the trilogy. I just hope the Newton entry is better than “Return of the Jedi.”
The University of Padua was founded in 1222! That is OLD. In fact, it’s the fifth oldest surviving university in the world. In four years, it’ll celebrate its 800th anniversary. Meravigliosa!
Brace your abdominal muscles for a stomach punch: his experiment did not occur at the Leaning Tower of Pisa.
- Apollo 13 secures the top spot for the heroism and problem-solving on the spacecraft and on the ground.
- Then comes Apollo 11, our first moon landing. Yes, I watched “First Man” this weekend’s, and yes, it was awesome.
- Earning the bronze is Apollo 8 for being the first manned mission to leave Earth’s orbit, circle the moon, and shoot the best photograph ever. I wrote more about Apollo 8 in my opening post of 2018. This December will mark the voyage’s 50th anniversary.
- Now we arrive at Apollo 15 for its confirmation of Galileo and being the first lunar mission to bring — wait for it — a car, colloquially and perfectly known as the “moon buggy.” Leave it to the middle-aged white guys at NASA to fly 250,000 miles then use a car to drive a couple more. If you don’t think the astronauts’ elbows stuck out of their moon buggy a few extra inches, you don’t know many middle-aged white guys.
- Speaking of middle-aged white guys doing middle-aged white guy things on the moon, coming in fifth is Apollo 14. American legend Alan Shepard made his long overdue return to space ten years after he became the first American to voyage into it. As the mission’s commander, he smuggled on board a makeshift 6-iron and a couple of golf balls to hit in the low lunar gravity. With characteristic golfer embellishment, he claimed he hit the ball for “miles and miles” even though it only went a couple hundred yards.
Two of those guys are still to come on this list. (Sorry, Kepler. Love your telescope.)
The most famous iteration of his trial has him ending on a defiant tone. After being forced to acknowledge that the earth is immobile at the universe’s center, he is said to have muttered under his breath, “E pur si muove” — “And yet it moves.” It’s probably his most famous quote, even if he didn’t say it. Another famous Galilean quote opines that the purpose of the Church “is to teach us how one goes to heaven, not how heaven goes,” but even then he was quoting someone else. Between these misattributions and the apocryphal Leaning Tower story, my high school education feels like one big lie. (No offense, Mr. Rourke.)
Inexcusably, Galileo’s heliocentric-proving “Dialogue” was not removed from the Index until 1835. An apology from the Church, where it finally admitted that it was wrong to treat Galileo as it had, did not come until Pope John Paul II mea culpa’d in 1992, the same year Bill Clinton was elected president and Michael Jordan led the Dream Team in Barcelona. Some might consider 359 years a bit overdue, but the Church has always made an art form out of moving at a glacial place.
Hilariously, Galileo is now used as an example by scientists who want religion kept out of scientific decisions AND by those who know little about science when they stand up to the mainstream opinion of scientists. When one’s struggle can be appropriated by two oppositional positions, that’s influence.