The proposed resolution of the Fermi Paradox in which the galaxy is silent because revealing your position is fatal. Every civilisation is a hunter moving through a dark forest; any other it detects is a potential threat whose intentions and rate of growth it cannot verify; and the cheapest move that is certainly safe is to destroy the other before it can become dangerous. Cixin Liu argues it in The Dark Forest, the second volume of his trilogy, published in 2008 and translated by Joel Martinsen in 2015. It is not argued in the first volume, which is where the site first credited it.
How the argument runs
It is built from two axioms, that survival is the first need of any civilisation and that matter in the universe is finite while civilisations grow, and from two mechanisms that follow. The chain of suspicion is the claim that two civilisations separated by light-years cannot establish whether the other is benign, because every message takes longer than the time in which intentions can change, and each must reason about what the other is reasoning about it. The technological explosion is the claim that a civilisation now far behind you can overtake you between one exchange and the next, so present weakness is no evidence of future safety. Together they make pre-emption the dominant strategy and silence the only defence.
Its weakness
It explains every observation, which is a warning sign rather than a strength, and it is not currently testable. More seriously it requires unanimity: one civilisation that broadcasts ends the equilibrium for everyone, and the incentive to broadcast is not obviously zero. Liu supplied the defector himself, in the first volume, in the listener who warns Earth off. Earth has already broadcast, in 1974, with the Arecibo Message, and nothing followed.
Connections
Fermi Paradox · Cixin Liu · The Three-Body Problem · METI · Arecibo Message · SETI · Trisolaris