Equilibrium selection

Equilibrium selection is the problem of choosing among multiple Nash equilibria in a game when rationality alone is insufficient to single out one. The challenge arises in coordination games, battle of the sexes, and other multi-equilibrium settings where mathematical solution concepts underdetermine the outcome. Proposed criteria include Pareto dominance, risk dominance, and various refinements of the Nash concept — but no universally accepted selection principle exists, and experimental evidence suggests that human players often ignore formal criteria in favor of salience and convention.

The failure to resolve equilibrium selection is not a technical gap but a philosophical one: it reveals that rationality, conceived as individual optimization, cannot by itself generate the shared expectations that social order requires.