“Aliens, The Fermi Paradox, and Dark Forest Theory: A Game Theoretic View”
One of my personal favorite pastimes is to watch conspiracy and supernatural “documentaries”, such as “Ancient Aliens” on the history channel. Thus, when I stumbled upon the article “Aliens, The Fermi Paradox, and The Dark Forest Theory: A Game Theoretic Overview” on a popular data science blog which I frequent, I knew it was evident that I write my blog post for networks about it.
As an overview, this article discusses the apparent contradiction between the number of probable alien intelligent civilizations and our lack of contact with any alien civilizations, and gives a theory which is then explained in terms of game theory as to why this may be.
This article begins with an explanation of the Drake equation. In 1961, Frank Drake, a professor of Astronomy at Cornell, formulated an equation for a probabilistic estimate of the number of intelligent alien civilizations in our galaxy. Using this equation, Frank Drake postulated that there were between 1000 and 100,000,000 planets with civilizations in the Milky Way Galaxy.
The Drake Equation
Continuing through the article, Since Frank Drake’s equation and postulation, there have been a numerous amount of attempts to contact extraterrestrial civilizations. Radio messages, deep space probes (voyager 1 and voyager 2), the Arecibo message. However, even with the amount of communication we have sent out into space, we have not received any substantial communication back. Henceforth, we hit the crux of this article. According to the Fermi Paradox, there exists a contradiction between the number of probable extraterrestrial intelligent civilizations and the fact that we have not received any contact. Or, put simply, given there are millions and millions of possible planets which could support extraterrestrial life, we should have received some sort of communication from extraterrestrial life by now.
So why could this be? Well, according Lin Cixin’s Dark Forest Theory, there do in fact exist the number of extraterrestrial civilizations postulated by Frank Drake, however, these civilizations intentionally forgo communicating with other civilizations out of fear of annihilation. Essentially, extraterrestrial civilizations have two options annihilate or be annihilated, so they will take steps to minimize their possibility of being annihilated.
This article then goes on to explain this theory from the lens of game theory. In particular, the Dark Forest Theory can be explained as a sequential, incomplete information game. Or, in layman’s terms, each player takes their turn in sequential order, and each player does not possess full information about their opponents or opponents’ strategies.
The first scenario highlighted in this article is of two civilizations which know of each other’s existence and can annihilate each other. In this situation one civilization takes its turn first, and then the second civilization takes its turn after. Additionally, each civilization has two strategies, annihilate the other civilization or do nothing. As explained by the author, it is a dominant strategy to annihilate the other civilization as soon as possible as it ensures positive payoff since the other will not be able to annihilate the first civilization.
The second situation highlighted is of two civilizations, who don’t know of each other’s existence, who have the options to broadcast their existences, annihilate, or do nothing. The caveat is they do not have the option to annihilate the other civilization unless the other civilization has broadcast their existence. In this game, since the two players do not know of each other’s existences, and the first player to broadcast is under the mercy of the second player, it is a dominant strategy for both civilizations to do nothing and not broadcast.
Two civilizations who do not know of each other’s existence
As explained at the end of the article, it becomes Pareto Optimal and Nash Equilibrium to destroy any civilization which one knows of, and to not broadcast one’s existence.
Overall, This article was a very interesting way to introduce and explain some new game theory concepts such as sequential games and I also thought it had some interesting takeaways regarding the flexible applicability of game theory.
Source: https://towardsdatascience.com/aliens-the-fermi-paradox-and-the-dark-forest-theory-e288718a808