Humans are lonely creatures. All we want is someone else to talk to in this universe. Yet aliens seem to be avoiding us, not broadcasting signals of their existence into space nor coming to meet us in galaxy-crossing spaceships.
This nonappearance is the basis of the Fermi paradox, first articulated in 1950 by physicist Enrico Fermi. While discussing extraterrestrial civilizations with some colleagues, he is said to have asked, “Where is everybody?” Astronomer Michael Hart and physicist Frank Tipler later elaborated on Fermi’s argument, pointing out that our galaxy contains around 300 million stars. If even a small percentage develop life capable of interstellar travel or communication, we should be awash in evidence of little green men. Over the years, many solutions have been proposed. Perhaps aliens are all too far away. Maybe they’ve forbidden contact with Earth. Or they might have decided it’s not worth traveling between stars.
But maybe it’s that when thinking about otherworldly civilizations, most people make simplifying assumptions about the history of technology. Many of the proposed solutions to the Fermi paradox seem to forget that aliens are going to be, well, alien. Which means there’s actually an extremely limited amount we can say with confidence about their culture and motivations. The biases inherent in the paradox suggest it’s telling us more about ourselves than anyone else.
But first, a little history. The 17th-century astronomer Johannes Kepler is best known for deriving the laws that explain planetary orbits. Originally from Germany, Kepler spent most of his life in small European towns and cities surrounded by protective walls. These fortifications—built to withstand enemy cannonballs—were based on advancements in mathematics and engineering from the preceding couple centuries. Kepler himself had lived for two weeks under siege in the city of Linz. So it’s interesting that in 1623, he wrote to a friend explaining that he had discovered “towns with round walls” on the moon.
Using the new technology of telescopes, astronomers at the time had been surveying our natural satellite. Many thinkers thought they saw evidence of vegetation and vast seas on the moon (which we now know to be dry volcanic plains). Kepler was one of the few who took a further step and speculated about intelligent lunar beings. In what is considered one of the first science-fiction novels, Somnium, he described how the far side of the moon might be a wild land of forests and strange men who lived in caves. But the side facing us was a milder place, whose rational inhabitants built enormous perfectly circular structures filled with “cantons, towns, and gardens.”
Kepler’s work, though fictional, was based on the best observations of his era. But the urban centers he thought he’d spied through his telescope were, in reality, empty craters. Despite his attempts at rational objectivity, his theories and assumptions were colored by the environment he’d grown up in. In looking at the moon, he projected similar structures to the fortified cities of 17th-centry Europe.
Flash forward to the late 1800s. Italian astronomer Giovanni Schiaparelli, who had originally studied civil and hydrological engineering, announced to the world that he’d spotted colossal straight lines—5,000 kilometers long and 120 kilometers wide—running across the face of Mars. Schiaparelli named these features canali, an Italian word that can mean both artificial structures like the Panama Canal and a natural waterway like the English Channel.
Other astronomers challenged his discovery, claiming they saw nothing like what he was describing. But the idea nevertheless took hold in the popular imagination. Its biggest champion was the American astronomer Percival Lowell, who built an observatory in the Arizona desert in 1894 to better observe Schiaparelli’s canali di Marte. Lowell considered the canals a product of rational minds and published map after map detailing their intersecting lines. He used then-popular ideas about social evolution to explain how Martian civilization had reached a later stage than ours. Mars, being smaller than Earth, evolved faster and was thus drying out and decaying. The intelligent beings of the Red Planet had banded together to transport water in huge canals in order to survive.
Schiaparelli first reported seeing canali in 1877. Eight years earlier, the Suez Canal had opened in Egypt to great fanfare. Around this same era, the people of Earth happened to be on a canal building spree, with projects like the Kiel in Germany, the Manchester ship canal in England, and the Panama Canal (begun by France in 1881). Lowell’s observations of a withering Martian civilization took place in the desolate Arizona desert. At the time, the U.S. federal government was working on plans to irrigate the drying west, constructing large reservoirs and systems to carry water great distances.
Schiaparelli and Lowell were both wrong. There are no perfectly straight lines on Mars and no dying civilizations. But much like Kepler before them, the two champions of Martian canals took the technological elements of their environment and gave them to intelligent creatures in space.
So what about the intellectual and cultural territory that the Fermi paradox sprang from? The radio telescope, generally suggested as the most obvious choice for interstellar communication, was invented in the 1930s. SETI pioneer Frank Drake, whose equation estimating the number of technological civilizations in our galaxy Hart and Tipler’s argument rests on, is a radio astronomer. The mid-20th-century has also been named the Space Age, the era when Soviets launched the first satellites into orbit and Americans sent men to the moon. Many thinkers in our time take it for granted that we will one day venture into the stars and colonize the galaxy.
Maybe giving alien civilizations radio telescope and spaceships is just as erroneous as assigning them canals and walled cities. We believe the technologies of our time are special, that there’s no way aliens could avoid inventing them. But that’s because we tend to think about technological evolution in simplistic terms—something like a tech tree from the Civilization video game series. First we invent the fire, then the wheel, then writing, and so on.
“The history of technology does not follow a single path that leads from stone tools to radio telescopes, or any other technological process or artifact,” wrote historian George Basalla in Civilized Life in the Universe: Scientists On Intelligent Extraterrestrials. “A more fruitful analogy is a many-branched bush with some technological branches fully developed while other branches are left unexplored, or partially explored and abandoned.”
When viewed backwards, technological progresses seems preordained. But the bushes of alien technology will likely start from different seeds and be nurtured by a different ecosystem than ours. There is nothing objective about the technology of our time. It’s always constrained by limitations of resources, environment, and imagination.
Consider something as basic as the wheel, invented in Egypt in the third millennium B.C.E. Past European thinkers marked it as a cornerstone of civilization but struggled to explain why it never turned up in Mesoamerica other than for small toy figurines. They missed the fact that the physical environment of the Mayans and Aztecs—a dense jungle, rugged landscape, and lack of draft animals—made the wheel impractical. In fact, in its own homeland of North Africa, the wheel was later replaced. Camels, an arguably “simpler” technology, proved to be better are moving materials efficiently through a desert terrain.
No technology is inevitable. We can no more assume that aliens have radio telescopes than that they have Frisbees, chocolate sundaes, instant coffee, trampolines, ballpoint pens, electric razors, or digital watches. Based on a single example—our own—people seem to believe we can predict technological pathways on other worlds. We provide alien civilizations with the ability to construct Dyson Spheres (megastructures that would capture the total energy output of a star) or achieve interstellar travel, all without knowing whether or not such things are possible. Fermi’s original point with his question of “Where is everybody?” was that galactic colonization might not be feasible.
We always have trouble overcoming our biases and seeing beyond our limited worldviews. As has been noted many times, speculation about alien civilization tends to hold up a mirror to ourselves. Perhaps then the Fermi Paradox is the ultimate manifestation of this fact; our own desires—to communicate, to explore—reflected back at us.