The Fermi paradox asks a simple question: Where are the aliens? If the universe is so vast, with so many Earth-like planets, and has existed for billions of years, then there should be some evidence of intelligent life out there… but there is none. Different hypotheses try to explain the Fermi paradox, and one of the most disturbing is the Great Filter: One of the steps in the evolutionary rise of a species is almost impossible to overcome, and life forms are essentially doomed to disappear.
Last November we explored the concept of emergence, a phenomenon that allows the creation of complex structures from simple elements, something fundamental to the development of life. So far, Earth is the only planet in the entire universe where this has happened. Our search capabilities are very limited, but if we consider the size of the universe, its age, the number of stars, the number of planets in general, and the number of planets with a compatible orbit (the so-called "habitable zone"), life should be much more abundant and easier to locate. However… the universe is dead, or at least, it appears so. Why?
The Great Filter and Its Two Scenarios
One of the most striking hypotheses is the Great Filter, proposed by economist (yes, economist) Robin Hanson. The Great Filter suggests that there is "something" preventing the mass development of life, beyond the situation humanity currently faces. At the same time, the Great Filter sets up two scenarios for our species: either we have an extra advantage (it could have been pure luck) that allowed us to leave the Great Filter behind and be the first to do so... or it lies in our future and we will turn to dust. Both scenarios carry a challenge, and that is lack of information. If the Great Filter is already behind us, we don't know what was the "critical point" that enabled its crossing, and if it lies in the future, besides being much more dangerous, it could take different forms.
Still, the Great Filter is bound to be absolutely devastating, beyond any doubt. Otherwise, if there is a remote possibility of surviving and recovering, it doesn't qualify as a Great Filter. One of the darkest ideas of the Great Filter is that when a species takes control of the planet, its path to self-destruction is inevitable. Large-scale thermonuclear wars, nanomachines out of control, conscious artificial intelligence that sees organic life as irrelevant, excessive genetic manipulation, and the species' own natural competition against itself are on that path. To conclude, the Kurzgesagt video presents something very worrying: The more abundant and complex life is in the universe, the higher the probability that the Great Filter will manifest in the future. So... do we really want to find aliens?
