Saved by the Dark Forest: How a Multitude of Extraterrestrial Civilizations Can Prevent a Hobbesian Trap

Abstract The possibility of extraterrestrial intelligence (ETI) exists despite no observed evidence, and the risks and benefits of actively searching for ETI (Active SETI) have been debated. Active SETI has been criticized for potentially exposing humanity to existential risk, and a recent game-theoretical model highlights the Hobbesian trap that could occur following contact if mutual distrust leads to mutual destruction. We argue that observing a nearby ETI would suggest the existence of many unobserved ETI. This would expand the game and implies that there may be a mechanism that prevents ETI from attacking us. As a result, the Hobbesian trap would be avoided if both parties assumed the other is not likely to attack.