Why Happiness Cannot Be a Stable State: Adaptive Becoming Theory and Human Functioning Under Persistent Mismatch

Happiness is commonly understood as a state that can be achieved and stabilized. This paper argues that assumption is structurally incompatible with how human experience operates. We propose Adaptive Becoming Theory (ABT), a process model grounded in the claim that human functioning is governed by continuous mismatch-driven reorganization. Individuals continuously generate expectations, encounter mismatch, and reorganize through response. Drawing from predictive processing, flow theory, self-determination theory, positive psychology, and existential perspectives, ABT integrates these domains into a unified framework in which happiness is not a terminal state but the subjective experience associated with effective engagement in ongoing adaptive reorganization. The paper derives four propositions, specifies boundary conditions and failure modes, develops a temporally nested account of the adaptive cycle, and presents cross-domain existence proofs drawn from clinical and organizational contexts. A set of falsifiable predictions is offered. The reframing is not rhetorical; it is a structural consequence of taking the model seriously.