The Dark Forest Theory

By Cansu Cicek

In the everlasting expanse of the universe, it is hard to believe that we might be the only forms of life within it. In our galaxy alone, there are billions of planets that reside in a star system's habitable zone that can theoretically sustain life. Even if a fraction of these planets harbour lifeforms, it would still mean that there are thousands of planets with life in the Milky Way galaxy alone. So, the question remains: if there is a such a high possibility that extraterrestrials exist, where are they?

Since the early 1950s, humans have been trying to answer this very question. We have been sending radio signals to the ever-expanding void of the universe and looking up upon the stars in hopes that we get a sign from somewhere or someone, yet we see nothing and hear nothing. This discrepancy between the lack of any evidence to support the claim that extraterrestrial life exists and the apparent high likelihood that life exists on other planets is called the Fermi paradox. Since the introduction of the Fermi paradox in 1950, many have tried to create a solution for it, leading to a plethora of theories and hypotheses about how life in our universe might occur and evolve. One such theory is called The Dark Forest Theory, which was first introduced to us in Cixin Lui's second book in his Remembrance of Earth’s Past trilogy, named The Dark Forest.

  In the book, the universe is stated to be like a dark forest where every civilization is like an armed hunter stalking through the trees like a ghost. Every action is calculated and delicate, making sure that the hunter doesn’t make any noise or take any action that would give away its position. The hunter must always be careful, as the forest is filled with other stealthy hunters like him. He does not know of the other hunters’ intent and must only ensure his own survival, no matter what. If he finds another hunter, there is only one thing that he can do: kill them before they kill him. If any civilization were to make themselves known in this dark forest, it would only bring about a guaranteed swift end to its existence. This is the terrifying solution to the Fermi paradox.

  To better understand the reason behind the hostility of cosmic civilizations, it is important to first understand a term that is stated as “The Chain of Suspicion”. For the sake of simplicity, let us state now that in the universe, there are only two civilized worlds. “Let’s call these two civilized worlds your civilization and my civilization. They’re separated by a great distance—say, a hundred light-years. You can detect that I exist, but you don’t know any details. However, I’m completely ignorant of your presence.”

  Now, before continuing, it is important to know two concepts that are given in the book called “benevolence” and “malice” between civilizations. These two words aren’t very rigorous and can be used too generally, so their meanings must be restricted. When applied to the realm of planetary civilizations, “benevolence” will be used to mention not taking the initiative to attack another civilization, while “malice” is the opposite.

  In the aforementioned case, neither civilization would be able to know whether the other is benevolent or malignant. Thus, the world that knows of the other's existence is at an advantage. If the civilization that has knowledge of the other is malignant, they will soon try to find ways to destroy the other and will only find solace when they achieve their goal.

 Now let’s say that the technologically superior civilization that knows of the other location is benevolent. It could potentially attempt to communicate with the technologically inferior civilization. However, the book also explains how this would not work due to the exponential nature of technological progress. Humans have existed for approximately 200,000 years, yet the vast majority of our technological growth has happened in the last 300 years. In the scale of the universe that has existed for billions of years, this cannot be stated as a mere progression but as an explosion. “On Earth, it took three hundred years, but there’s no reason why humanity should be the fastest of all cosmic civilizations. Maybe there are others whose technological explosions were even more sudden. I’m weaker than you, but once I’ve received your message and know of your existence, the chain of suspicion is established between us. If at any time I experience a technological explosion that suddenly puts me far ahead of you, then I’m stronger than you.” 

Once the weaker civilization receives the message and gains knowledge of the existence of the other, it will set off that explosion, meaning that although they currently pose no imminent threat to the technologically superior civilization, there is no guarantee that they won't become a great danger in the future. Thus, it is in the other's greatest interest to destroy them before the weaker civilization reaches that level of technology.

Even if both civilizations think the other is benevolent, neither of them can feel safe, as they have no way of knowing what the other thinks of it. This is the chain of suspicion. “They don’t know what we’re thinking about, what they’re thinking about, what we’re thinking about, what they’re thinking about, what we’re...” On earth, the chain of suspicion can be resolved quickly, as most disputes can be resolved within 2 to 3 of said chains as we speak a common language and have a means of efficient communication. None of this is present between species that are light years away from one another. It is impossible to even know if our means of communication can be understood by other species or if they can understand us. 

“In actual cosmic civilization, the biological differences between different groups might be as high as the kingdom level, and cultural differences are even further beyond our imagining. Add to this the vast distances between them, and you have chains of suspicion that are practically indestructible." If the other civilisation were indeed benevolent, communication could potentially be made to join forces; however, if it were not, the technologically weaker one would surely be destroyed.

  “The most important aspect of the chain of suspicion It’s unrelated to civilization’s own morality and social structure. It’s enough to think of every civilization as the point at the end of a chain. Regardless of whether civilizations are internally benevolent or malicious, when they enter the web formed by chains of suspicion, they’re all identical.” 

In the great expanse of the dark forest, each civilization only has three options. Hide and hope that none of the other civilizations will detect you, putting your planet at risk by keeping yourself blinded and in the shadow. Reveal yourself in hopes of finding others who share a similar intent of being peaceful, but risk those who don’t share that common sentiment destroying you. Or kill the other, eliminating the possibility for it to ever threaten you yet risking your own position being found. I believe that this answer to the fermi’s paradox was best described by British science fiction author Sir Arthur C. Clark, who stated, "Two possibilities exist: either we are alone in the university or we are not. Both are equally terrifying.”

Bibliography

Liu, C. and Martinsen, J. (2021) The Dark Forest. London: Head of Zeus -- an AdAstra book. 

O’Callaghan, J. (2021) What is the fermi paradox?, LiveScience. Available at: https://www.livescience.com/fermi-paradox (Accessed: 06 November 2023). 

The Fermi paradox: Where are all the aliens? (no date) Encyclopædia Britannica. Available at: https://www.britannica.com/story/the-fermi-paradox-where-are-all-the-aliens (Accessed: 06 November 2023). 

The terrifying solution to the fermi paradox. (2023) YouTube. Available at: https://www.youtube.com/watch?v=cdmADelND1g&t=504s (Accessed: 06 November 2023). 

Why is space malicious? | three body problem series (2022) YouTube. Available at: https://www.youtube.com/watch?v=DjoICDmv4oM&t=902s (Accessed: 06 November 2023).