It’s fitting that Darwin and Galileo celebrate anniversaries in 2009: Arguably more than any other scientists, they expanded our horizons and showed us our place in the universe.
This year is a big one for anniversaries in science: It was 400 years ago this fall that Galileo aimed his telescope at the night sky, and it’s been 150 years since Charles Darwin penned his On the Origin of Species; earlier this year we marked the biologist’s own 200th birthday. So far, it’s hard to say which of the anniversaries is the bigger deal. Scientific American and National Geographic have put out special Darwin-themed issues, while Britain has minted a commemorative two-pound Darwin coin; the United Nations meanwhile has declared 2009 the International Year of Astronomy, in honor of Galileo’s achievement, while the astronomer’s likeness can be found on a commemorative twenty-five-euro coin. Countless academic conferences and public events will honor both men throughout the year.
It’s just a coincidence, of course, that both Galileo and Darwin are having anniversaries at the same time. Indeed, we don’t usually think of these two great thinkers together. They lived two centuries apart; they worked in different countries, and made their mark in very different fields. Even so, I can hardly think of a more fitting pairing than these two intellectual giants—two men who, perhaps unintentionally, transformed the way we conceive of the universe and our place within it.
When we take a closer look at their legacies, we see just how much in common Galileo and Darwin actually had. Both men, of course, have become icons of science, their achievements having taken on mythological status. Each of them triggered a revolution, not only in our perception of the universe itself, but in the way we imagine our relationship with the world around us—and adjusting to this new relationship has not always been easy. As Sigmund Freud put it, the work of these two scientists forced humanity to endure “two great outrages upon its naïve self-love.” The first outrage, sparked by Copernicus but only taken seriously after Galileo’s observations, was that Earth is not special: It is merely one of several planets orbiting a much larger sun. The second outrage is that mankind is not special: We are a part of the animal kingdom, one small twig on the vast “tree of life,” to use Darwin’s metaphor. It is hardly a surprise that the work of both men was perceived—in some circles, at least—as a grave threat to the established order.
Neither of these great figures set out to change the world. Galileo had initially thought of becoming a priest; his father, a respected musician, imagined him becoming a doctor. Instead he became a professor of mathematics. When he first got hold of the telescope—a Dutch invention that quickly made its way to Italy—Galileo initially saw its value as a military tool. In 1609 he led a procession of Venetian dignitaries to the top of St. Mark’s Cathedral, where he encouraged them to look through the “perspicillum”; he boasted of its power to identify ships more than two hours before they arrived in port. A full two months went by before he aimed the device at the night sky. (He eventually discovered the four “Galilean moons” of Jupiter, below.)
Darwin’s career took similar twists and turns. His father, a doctor, sent him off to medical school. Showing no great aptitude, Darwin trained to be a clergyman. The relaxed life of a country pastor loomed ahead. Only by a quirk of fate did he end up taking a berth onboard HMS Beagle—invited by the captain, a young aristocrat named Robert Fitzroy, more for intellectual companionship on the long voyage than for any particular scientific purpose. (Indeed, the ship already had a naturalist—the rarely-mentioned Robert McKormick, who was also the ship’s surgeon.)
Neither Galileo nor Darwin was a “genius” in the traditional sense—yet they were keen observers, and, more importantly, they understood the significance of what they were seeing. Galileo carefully recorded the strange sights his telescope revealed: The planet Venus appeared to go through phases like our own moon, suggesting that it orbits the Sun rather than Earth. Four “stars” appeared near the planet Jupiter, shifting their position from night to night but never straying from Jupiter’s side; they were, he reasoned, moons of the bright planet. Both of these discoveries contradicted the notion of an Earth-centered universe, an idea espoused by the ancient Greeks and embraced by the Roman Catholic Church; instead, they seemed to support the sun-centered (“heliocentric”) model of Copernicus. Galileo also saw dark spots on the sun, as well as mountains and craters on the moon—all of which contradicted the view of the sun and the moon as perfect spherical bodies, another cornerstone of the medieval worldview. Once thought to be pure and flawless, the moon and planets now appeared to be rather similar to our own world. Galileo had brought the heavens down to earth.
Darwin’s path echoes that of Galileo. “I have no great quickness of apprehension or wit which is so remarkable in some clever men,” he wrote in his autobiography. Nor was he the most astute chronicler of nature: He at first thought his now-famous Galapagos finches were grosbeaks. But he worked tirelessly, amassing more than 1,700 pages of notes (along with more than 5,000 specimens) over the course of the five-year voyage. And he had a remarkable ability to distill and interpret those observations. “My mind,” he later wrote, “seems to have become a kind of machine for grinding laws out of a large collection of facts.”
One “law” in particular is what we now remember him for: evolution by means of natural selection. (Evolution itself wasn’t new—the idea was certainly “in the air” by Darwin’s time—but the mechanism, natural selection, was a bold new idea.) Different species, descended from a common ancestor, came to take on their present form gradually, over millions of years. Although he put off the question of human origins for a later book (The Descent of Man, published in 1871), the writing was on the wall. Humans were a part of the animal kingdom; we and our closest cousins, the great apes, evolved from an ape-like ancestor in the remote past. One can hardly underestimate the impact of this bold new vision of the natural world. Stephen Jay Gould called it “the greatest ideological revolution in the history of science”; Richard Dawkins calls it “the most important idea to occur to a human mind.”
It was, of course, just the beginning. A Czech monk named Gregor Mendel worked out the laws of inheritance in 1865—less than a decade after Origin—but more than thirty years would pass until the significance of his work was recognized, and it wasn’t until 1953 that James D. Watson and Francis Crick discovered the structure of DNA, illuminating the machinery of evolution at the molecular level. The full significance and scope of Darwin’s theory had finally become clear: It is the unifying framework that makes sense of nature’s diversity. As geneticist Theodosius Dobzhansky wrote nearly forty years ago, “Nothing in biology makes sense, except in the light of evolution.”
Only when we look at the personalities of Darwin and Galileo do we see a sharp difference. Darwin was the quintessential family man, raising eight children with his devoted wife (also his cousin), Emma Wedgwood. (Two other children died in infancy, while one of the eight, his beloved daughter Annie, died at the age of ten—causing Darwin great distress.) Emma remained by his side throughout his adult life. Galileo never married, but nonetheless fathered three children with a Venetian woman named Marina Gamba. Marina joined Galileo in Padua while he worked there, but did not come with him when he moved to Florence under the patronage of the Grand Duke of Tuscany. Their son, Vincenzo, was eventually legitimized; the two daughters, considered unmarriageable due to the circumstances of their birth, were sent to a local convent where they became nuns.
Darwin was gentle and unassuming, an English squire eager to please his friends, family, and colleagues. In fact, he went out of his way not to offend those around him. Knowing that the theory of natural selection would provoke controversy, he delayed publication for two decades. He finally set his ideas in print only when it was clear that another naturalist, Alfred Russell Wallace, was on the verge of publishing a virtually identical theory. Galileo, in contrast, was outspoken and arrogant; he seemed to welcome disputes and arguments. As philosopher of science Michael Ruse has put it, Galileo was “a man whose ego was off the high end of the scale.”
Mild-mannered as Darwin may have been in person, he pulled no punches in his writing. He famously described the Origin as “one long argument.” It sold out its first edition almost instantly, and ran through six more editions in the next dozen years. Galileo’s Starry Messenger, in which he described his telescopic observations, was also an instant hit, captivating readers across Europe and beyond. Moreover, both Origin and Starry Messenger—as well as Galileo’s later treatise on the structure of the solar system, his Dialogue Concerning the Two Chief World Systems—were told in simple, non-technical language that any educated layman could follow. And yet they were more than expositions: They were, in fact, forceful polemics designed to sway the reader to a particular interpretation of the facts. (Galileo’s Dialogue was purportedly a “balanced” comparison of the competing systems—that of the ancient Greek philosopher Ptolemy, and the new model described by Copernicus—but was actually a thinly-veiled endorsement of the Copernican system.)
Both of these revolutions were, on the surface, an affront to “common sense”—of course we live at the center of the universe; of course we are distinct from the animals—and a threat to established religious traditions in particular. Indeed, the controversies that swirled around both Galileo and Darwin have become emblematic of the supposed “war” between science and religion, though neither was as simple as is often portrayed.
Far from being hostile to science, the Catholic Church was, in Galileo’s day, the primary sponsor of astronomical research; the authorities in Rome relied on the astronomers to determine the date of Easter, the holiest day in the Christian calendar. Modern historians also question the oft-repeated allegation that Copernicus and Galileo had “dethroned” mankind; on the contrary, by describing Earth as a planet, one could argue that Copernicanism “elevated” humanity to the celestial realm. In any case, Galileo seems to have incurred the wrath of the Inquisition more for disobeying orders than for his support of the heliocentric model per se. The Galileo affair appears to have been largely a turf war. The Church, already battling Protestants north of the Alps, had no patience for an arrogant astronomer who dared say that there was more than one way to the truth—that while priests interpreted the book of scripture, anyone could study the “Book of Nature” with the right tools and an open mind.
The danger with Darwin is more obvious. While the structure of the solar system may seem of little practical consequence, the question of human origins was a profound one for anyone with traditional Judeo-Christian beliefs. How could mankind be the “special creation” of an omnipotent, benevolent God—a God who cares about us in particular—if humans evolved through natural processes, just like all the other creatures?
Of course, times had changed between Galileo’s day and Darwin’s. Merely a decade before Galileo aimed his telescope skyward, his countryman, the philosopher Giordano Bruno, had been burned at the stake for his heretical views on cosmology and other matters; Galileo, forced to renounce his support for the Copernican system, got away with a life sentence. (One could describe it as “house arrest”: Galileo spent the final years of his life confined to his villa outside Florence).
By Darwin’s time, the authority of the Church—already long divided between Catholicism and numerous Protestant denominations—had far less power, and far less interest in confronting scientists about particular discoveries. As Ruse points out, most Protestants had simply come to terms with “the Genesis problem” by admitting that the biblical account of creation was metaphorical. Catholics, meanwhile, seemed content to stay out of the debate. As Ruse puts it, “their fingers had been burned” over the Galileo affair, and were “glad to let the Protestants run with this one.” (Galileo's preserved finger, above.)
As Darwin biographer Cyril Aydon explains, the Church simply “set the boundaries of its authority in a different place.” Darwin was in no danger of suffering Bruno’s (or even Galileo’s) fate. “He wasn’t even in danger of excommunication,” Aydon writes, “except from a few dinner tables, most of which he would not have wanted to sit at anyway.” In the end—after significant lobbying by friends in high places—Darwin was buried in Westminster Abbey (left). The London Times called him “the greatest Englishman since Newton,” who happens to lie nearby.
Yet religiously-minded people bristled at the implications of Darwin’s theory. There were, of course, moral concerns: If we were descended from ape-like creatures, wasn’t there a danger we would behave like apes? Even worse, evolution hinted at a purposeless universe, one in which chance played a greater role than design. (Efforts by certain conservative groups to bring a designer back into nature—first though creationism, and more recently through “intelligent design”—have failed, but they hardly come as a surprise.)
With his telescope, Galileo, too, revealed a vast and seemingly uncaring cosmos. When Earth was thought to rest at the center of a relatively comfortable little universe, we might imagine that we somehow played an important role in cosmic affairs, even if the stars and planets were unknowable. Now we do know them, and, though there is much that we are ignorant of, there is no doubt of our smallness. As physicist Steven Weinberg famously said, “The more the universe seems comprehensible, the more it also seems pointless.”
Both Galileo and Darwin showed us that our place in the cosmos is less central—perhaps less special—than we had imagined. For some it has been a bitter pill to swallow. But there is also every reason to rejoice in these discoveries. We are indeed animals, but very clever animals—animals that can comprehend the structure of DNA and the unity of life. And yes, we live in one remote corner of the galaxy, itself one of billions of galaxies—but from this outpost we have probed the architecture of the universe, from the smallest quark to the most distant quasar. Looking back in this anniversary year, we should remember Galileo and Darwin as two great thinkers who broadened our horizons, perhaps to a greater degree than any other figures in history. As a result of their vision, we live in a larger, more cohesive, and more wonderful universe.
Dan Falk has written about science for the Globe and Mail, the Toronto Star, the Boston Globe, Astronomy, Sky & Telescope, and New Scientist. His radio documentary work has garnered several international awards, and his first book, Universe on a T-Shirt, won the 2002 Science Journalism Award from the Canadian Science Writers’ Association. His most recent book is In Search of Time: The Science of a Curious Dimension. He lives in Toronto.
