How Octopuses and Uncontacted Tribes Help Explain the Fermi Paradox

If life is abundant throughout the universe, why hasn't anyone come calling? This question summarizes the Fermi Paradox, the apparent discrepancy between the speculated likelihood of intelligent life existing on other planets and the lack of convincing evidence that such life has ever contacted Earth. There are many explanations for the Fermi Paradox, often revolving around the evolution of intelligent life and its sustainability. However, this article focuses on insights that we can draw from the only civilization-building species we know: humans. Specifically, I make two arguments: first, the existence of an intelligent, ultrasocial species is no guarantee that that species will develop interstellar travel; and second, an advanced alien civilization may already be aware of Earth but is reluctant to, or has no interest in, making direct contact.

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The Paradox

To better understand the origins of life, scientists Stanley Miller and Harold Urey recreated the conditions of a primordial Earth inside their laboratory at the University of Chicago. Their experiment consisted of a 5-L flask filled with water (to simulate Earth's early oceans) and another filled with methane, ammonia, and hydrogen (gases believed to have made up Earth's atmosphere approximately 3.7 billion years ago). The flasks were connected via glass tubing. When Miller and Urey heated the ocean flask, water vapor would pass through the atmospheric flask. This mixture of water vapor, methane, ammonia, and hydrogen was then periodically zapped with electric sparks, simulating lightning strikes. The laboratory equipment was entirely sterile. However, after the experiment ran for just one week, Miller and Urey found that organic compounds had accumulated inside their primordial ocean—specifically, amino acids, the building blocks of all life on Earth.

The Miller-Urey experiment has since been replicated countless times, using more accurate approximations of the conditions and chemicals present on our planet billions of years ago. They all conclude that simple elements can spontaneously form into organic compounds with enough time and enough exposure to some kind of energy source, be it a meteor strike, volcanic eruption, lightning, or hydrothermal vents. In fact, in their search for life outside Earth, NASA now looks for three criteria: water, chemistry (including elements like carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur), and energy.

Evidence suggests that planets that meet these three criteria are common throughout our universe. In our solar system alone, we know of at least two strong candidates (excluding Earth) that likely contain water, chemistry, and energy: Europa and Enceladus, two moons that orbit Jupiter and Saturn respectfully and likely contain liquid oceans under their icy surfaces. In the case of Enceladus, NASA has even confirmed that it has the right chemistry after the Cassini probe passed through plumes of water vapor ejected from the moon's south pole and found hydrocarbons. Other potential candidates for extraterrestrial life seriously considered by NASA within our solar system include Titan (a giant moon orbiting Saturn with a dense atmosphere of nitrogen and liquid methane oceans) and ancient Mars (which may have supported a vast ocean of water).

And that's just our backyard. The Milky Way is estimated to contain 100-400 billion stars, with each star having—on average—one exoplanet (the number is likely higher due to limitations in exoplanet detection). Some estimates suggest that, of these hundreds of billions of exoplanets, a few tens of billions are earth-sized and orbit their suns at a distance suitable for liquid water. This estimate doesn't account for how life could emerge on non-earth-sized planets too far or too close to the sun for liquid water, like within an underground ocean surrounded by thick layers of ice and rock (e.g., Europa and Enceladus). Beyond the Milky Way, the numbers become more unfathomable. There are somewhere between 200 billion and 2 trillion galaxies in the observable universe, each filled with billions of stars and planets of their own. These incomprehensibly large figures have led some famous scientific figures to conclude that it is "unrealistic," even "arrogant," to think that humans are alone in the universe.

But where are all the aliens? Many of these solar systems containing Earth-like planets are millions, hundreds of millions, maybe even billions of years older than Earth. Human civilization has existed for less than 10,000 years, and we are already on the cusp of interstellar travel (Voyager 1, the most distant man-made object from Earth, is already in interstellar space). Imagine what a civilization one million years older than our own might be able to accomplish (that's one thousand times more time than humanity has had from the invention of agriculture to the present). One would assume—given the incomprehensibly large number of potentially habitable planets—that such a civilization would have already gone interstellar and visited Earth. Or that we would have at least encountered signs of such a civilization, such as their electromagnetic waves or space probes. However, no convincing evidence exists that aliens have visited or contacted Earth.

This discrepancy between observation and seemingly well-founded speculation is known as the Fermi Paradox. The number of proposed explanations for the Fermi Paradox almost rivals the number of stars in the Milky Way. Such as that the arc of evolution does not necessarily tend towards more intelligent life, that natural disasters periodically wipe out a planet's complex organisms, or that it is the nature of intelligence to destroy itself. Questions of evolution and life sustainability aside, this article uses anthropological insights from humanity's history to explain the Fermi Paradox. First, technological advancement is not guaranteed to occur even in an intelligent, ultrasocial species whose civilization has existed for thousands of years. Second, an advanced alien civilization may already be aware of Earth but is reluctant to, or has no interest in, making direct contact.

Part One: The Preconditions for Civilization

To demonstrate how the odds of an interstellar civilization existing in our galaxy are much smaller than we might think, consider how intelligence is no guarantee that a species will develop technologically. As an example, consider the octopus. Having evolutionarily split from vertebrates 600 million years ago, octopuses may be the closest thing we have to hypothetical extraterrestrial intelligence. Despite the distant relation, octopuses have independently evolved remarkable, mammal-like cognitive abilities. They regularly use tools, like coconut and bivalve shells, for protection and hunting. They often build walls around their den out of stones, shells, and bits of broken glass. They can solve complex puzzles (like opening jars and stealing bait from lobster traps). When their minds lack stimulation, Octopuses will show signs of play, like releasing floating toys in the circular currents of their aquariums and then catching them. Or they might lash out, like one octopus, Otto, did at an aquarium in Germany. When bored, Otto would juggle his fellow tank mates around, throw rocks at the glass, and even cause a short circuit by crawling out of his tank and shooting a jet of water at an overhead light.

But we live on a planet of the apes (humans being a species of great ape) rather than a planet of the cephalopods. Intelligence itself does not guarantee civilization. Instead, two additional criteria (amongst others) are also necessary: a long lifespan to accumulate knowledge and the ability to pass that knowledge down between generations. Octopuses don't measure up well to these criteria. The common octopus lives, on average, just 1-2 years in the wild and leads a very solitary life. This means each individual octopus has just a couple of years to figure everything out before their knowledge is erased and their offspring have to start all over. Even if octopuses had greater than human intelligence, they would never be able to advance technologically (think how much technology a human develops before turning two).

Other intelligent animals score better against these two criteria. Whales live long lives (humpback whales can live 80-90 years in the wild) and show evidence of teaching: different pods of killer whales often have unique hunting techniques and even dialects. Elephants also live relatively long lives (averaging 60 years), pass knowledge between the generations, and even have a long, sensitive trunk they can use to manipulate small objects. However, no animal comes close to the supercharged teaching abilities of humans. We are ultrasocial learning machines who invest vastly more time and resources in educating our young than any other species on Earth.

Learning from others is one of humanity's greatest superpowers, possibly more important to technological advancement than individual intelligence alone. A thought experiment outlined by anthropologist Joseph Henrich makes this clear. Imagine a planet inhabited by two tribes: the Geniuses and the Copycats. The Geniuses are highly intelligent, and one in ten invent a unique technology within their lifetime (say, a fishing rod). The Copycats aren't as clever, and only one in every thousand is smart enough to invent a fishing rod. However, the Copycat's strength is their ability to learn from each other. The Geniuses can only teach one friend how to make a fishing rod, while the Copycats can teach ten. Next, suppose that passing the knowledge of fishing onto a friend is only successful half the time. The question is: which group profits most from the technology? If you run the calculation, only one in five Geniuses will learn the mysteries of the fishing rod, while 99.9 percent of the Copycats will eventually master the technology (by figuring it out for themselves or being taught by other tribe members). As such, the Copycats will advance much faster technologically than their more intellectually well-endowed rivals, the Geniuses.

However, not even intelligence coupled with a long lifespan and ultra-sociality is enough for civilization. Henrich's thought experiment also alludes to another precondition for advanced civilization: large, interconnected populations. Large populations increase the chances that an innovative genius will be born in the first place, and interconnectedness allows the genius's ideas to spread to many minds, where they can be safely stored, built upon, and then further passed along. Large, interconnected populations of people (in the order of thousands or millions) are so crucial for technological progress that humans can technologically regress when isolated. One of the most striking examples of such regression comes from the indigenous peoples of Tasmania. The first humans to reach Tasmania arrived with a bundle of technology familiar to most peoples living on mainland Australia 35,000 years ago. However, 10,000 years ago, rising sea levels turned Tasmania into an island, completely isolating its small number of inhabitants from the rest of the world. By the time Europeans first encountered the Tasmanians, they had lost many technologies that their own ancestors had once possessed, like bone tools, cold-weather clothing, fishhooks, hafted tools, barbed spears, fish traps, or spear throwers. Without multiple minds where knowledge could safely be stored, much of it was lost as elders passed away. With a small social network, innovations were less likely to emerge and spread.

Although humanity would eventually acquire large, interconnected populations, such a development was far from inevitable. For most of human history—around 290,000 years—we existed in small tribes of hunter-gatherers. During this period, almost no significant technological progress was made. In small, isolated tribes, it was difficult for innovations to spread, and the knowledge a tribe did accumulate could easily be lost in, say, a natural disaster that kills off their tribes' elders or a dawn raid that leaves most of the adults dead or abducted. It was not until the invention of farming 10,000 years ago that human technological advancement took off. Farming allowed for densely populated cities where the minds of many thousands, even millions, of people could come together and generate and store knowledge en masse. However, widespread farming was only made possible thanks to a climate anomaly 10,000 years ago: Earth's temperature became unusually warm and unusually stable. If this anomaly had not occurred, it is easy to imagine how humanity may have continued living as hunter-gatherers for another 10,000 years, never achieving the large, stable populations required for technological advancement.

Overall, the chances of an intelligent, interstellar species existing within our galaxy are much smaller than we might initially think. Even if we assume that intelligence is abundant, it may be short-lived and asocial. Even if it is both long-lived and ultrasocial, it may never achieve the large, interconnected populations required for technological advancement. The above insights do not even consider the fact that an intelligent, long-lived, ultrasocial lifeform might not even be interested in building a civilization—or, at least, space exploration—in the first place.

But there is another possibility. Maybe they are already here; we just don't know it…

Part Two: The Reluctant or Uninterested Alien

In Brief Answers to the Big Questions (2018), Stephen Hawking dismisses the possibility that aliens have already visited Earth, writing, "I think that any visits by aliens would be much more obvious—and probably also much more unpleasant" (p. 83). I disagree. There are several reasons why Aliens may visit Earth and choose not to make contact, or at least not make any obvious contact with humanity. The two arguments I discuss here are that aliens choose to refrain from direct contact or have no interest in making contact.

In the Bay of Bengal lies a small landmass, North Sentinel Island, home to the Sentinelese, an uncontacted tribe living in voluntary isolation. The Sentinelese number between 35 and 400 individuals. They are believed to be descendants of the first humans out of Africa and may have lived on the island for as many as 60,000 years. The Sentinelese have been so isolated for so long that their language is mutually unintelligible with languages from other nearby Andaman islands. Out of fear that contact with outsiders may destroy their unique way of life and expose the Sentinelese to diseases to which they have no immunity, the Indian Government has set up an exclusion zone around the island, forbidding any unauthorized contact. This exclusion zone is also for outsiders' protection, given the extreme hostility the Sentinelese tend to show visitors.

The Sentinelese and other uncontacted peoples provide an analogy for understanding why an advanced alien civilization may be aware of Earth but choose not to make contact. Perhaps an advanced alien civilization has set up a similar protective zone around Earth, preventing direct contact and only allowing brief visits by scientists to discretely study humanity. Perhaps, similar to the Indian government, this alien civilization fears that direct contact could expose Earth to interplanetary contamination and ruin any insights they might gain from studying the natural, isolated development of our society. UFO sightings may be rare glimpses that humanity gets at this planetary preservation project. Similar to how uncontacted peoples might stare in bewilderment at passing aircraft, wondering why, if there are people within these flying machines, they do not come down and announce themselves.

Another possibility is that any interstellar aliens in our galaxy are so advanced that they simply have no interest in contacting us or no way to communicate with us that we could even comprehend. For example, say humans discover an ant colony in the Amazon Rainforest. Should the United Nations send a special envoy to make "contact" with the ants and welcome them into the international community? It is hard to imagine even a single human taking an interest in such a discovery and making a long trek through the Amazon to find this specific colony. And even if someone did, how would they initiate contact with the ants? Perhaps one could decode their complex language of pheromones, but this language is likely limited to things important to ant life, like "follow me. I found food", "let's dig here," and "the colony is under attack!". There would be no way for us to express that the human explorer comes from a vast, technologically advanced civilization, that the ants live in a place called Brazil, or "take me to your queen." Perhaps what is arrogant is not assuming that we are alone in the universe, but that we would be interesting enough for an alien civilization to travel thousands of light years to visit. If this civilization has already discovered how to travel across the galaxy, it is unlikely that we have anything interesting to offer them.

Conclusion

To conclude, humanity may be more of a cosmic miracle than we realize. Our civilization only appeared thanks to a long chain of flukes. And even then, we have barely escaped our solar system, having only sent two, now barely operable, probes weighing a collective 1.4 tons beyond Pluto. Who knows if we will ever travel to even our closest star before our civilization ends? On the other hand, maybe interstellar civilizations are abundant, and they view us as something to be studied from a distance, or they are so advanced they take little interest in establishing contact with a species that could never comprehend them.