Abstract

Classical evolutionary game theory rests on a hidden assumption: that an actor holds a definite strategy, pure or randomized, before it ever interacts. Yet human and organizational choices routinely violate this premise, displaying interference, order, and framing effects that classical probability cannot accommodate. We propose a framework in which an economic actor is genuinely undecided before market entry, modeled as a strategic superposition of pure strategies in a Hilbert space, and in which interaction acts as a measurement that collapses this state onto a realized strategy with Born-rule probabilities. Populations are described by a density operator whose diagonal carries strategy frequencies and whose off-diagonal coherences encode maintained superposition, evolving under a strategic master equation that couples coherent deliberation, decoherence in the strategy basis, and a replicator selection superoperator. Three results follow. A square-root representation places quantum normalization and evolutionary selection on a common geometric footing; the classical replicator equation emerges exactly as the strong-decoherence limit, with an explicit error bound; and strategy realization becomes basis-dependent through interference that no classical mixture reproduces. In a two-strategy market game, coherent coupling displaces the evolutionarily stable strategy by order Δ2/γ, recovering the classical value as decoherence dominates. The construction formalizes constitutive self-opacity and links bounded rationality to quantum interference, positioning classical evolutionary dynamics as one limiting regime of a broader strategic dynamics.

Keywords