Two wrongs make a right

Biological Parallel

Vampire bats practice reciprocal blood sharing—but bats that have been cheated are more likely to cheat others in future interactions, creating cycles of retaliatory defection. This 'tit-for-tat with vengeance' spreads defection through the network despite decreasing everyone's long-term fitness. The two-wrongs fallacy exploits reciprocity instincts where matching others' behavior (even negative behavior) feels like restoring balance. Evolutionarily, conditional cooperation was adaptive, but the logic 'they defected, so I can too' creates destructive equilibria when defection becomes normalized.