The universe is a dark forest. This comparison is central to the science fiction novel The Dark Forest, by Liu Cixin, and is the premise of a chilling theory that seeks to answer an eternal question: if there is life on other planets, why haven’t they contacted us? The answer to this cosmic question has been widely discussed in books and films, but also in scientific circles.
The theory responds to two postulates existing in the scientific community: the Drake equation and the Fermi paradox. The first takes the variables involved in the question of extraterrestrial life and produces a mathematical result. According to Drake’s equation, by now we should have encountered at least 20 alien civilizations in the solar system.
Despite this, what we know so far is absolutely zero. The discordance between these factors is the central axis of the Fermi paradox. If there are so many possibilities of encountering alien civilizations, why haven’t we been contacted by one? The dark forest postulate dares to go further than this irresolvable paradox. Cixin’s novel presents these arguments:
Every form of life wants to stay alive.
There is no way to know if other life forms can or will want to destroy you if given the chance.
Since there are no certainties, the safest option for any species is to annihilate other life forms before they do the same to them.
Because extraterrestrial civilizations could be guided by these precepts, the behavior they take in Cixin’s novel is silence. Why risk being discovered if it means imminent danger? If the universe is a dark forest about which we know almost everything, the wisest way to navigate through it is with the caution of a hunter who can be hunted at any moment.
How plausible is the dark forest theory?
This postulate has its roots in fiction, but that does not mean that it has no logic. Actually, the dark forest theory is quite plausible for the simple fact that it is not as risky as it seems. No speculation is made about the qualities of the alien civilizations, about their form of communication or their technological advances.
The theory of the dark forest only considers the ever-present possibility of silence, and is not a universal postulate. It would only be enough for an alien to act with this dark paranoia to confirm it. In any case, to know this we would have to receive signs of life beyond Earth, something that has not happened to date. If one day we receive news from other universes, we will only have to hope that they are signs of peace and not war.