The Failure of State-Based Models of Human Functioning: Toward a Process Theory of Continuous Adaptive Reorganization

State-based models of human functioning have shaped research across cognitive science, neuroscience, clinical psychology, and well-being theory, providing tractable frameworks for measurement, classification, and intervention. These models conceptualize cognition, emotion, and behavior as configurations that can be entered, observed, and, in some cases, stabilized. This paper argues that their limitation is not empirical but structural. By treating human functioning as transitions among discrete internal states, they rely on a mis-specified unit of analysis that cannot adequately represent systems organized around continuous, recursive interaction. Drawing on evidence from dynamic systems theory, enactive and embodied cognition, process-based clinical science, and contemporary critiques of categorical models, the paper demonstrates that human functioning unfolds as a temporally extended process characterized by multicausality, context dependence, and persistent variability. These features are not peripheral complications but defining properties of the system. As such, they cannot be captured through models that assume stability, discreteness, and fixed internal representations. In response, the paper advances a process-oriented alternative grounded in Adaptive Becoming Theory (ABT), which models human functioning as a recursive cycle of expectation, mismatch, response, and reorganization across multiple timescales. Within this framework, what have traditionally been described as states are reinterpreted as temporary coherence, local stabilizations within an ongoing process that does not resolve into equilibrium. Well-being, accordingly, is not a condition to be achieved but the experiential correlate of effective engagement in continuous adaptive reorganization. The paper contributes by reframing the unit of analysis in human functioning, integrating convergent process-theoretic perspectives grounded in process ontology into a coherent account, and outlining implications for research, theory, and practice. This paper forms the theoretical ground-clearing contribution of a two-paper canon. The companion paper, Morgan (2026b), develops the positive process-theoretic alternative formally introduced in Section 4.5: Adaptive Becoming Theory, a recursive cycle of expectation, mismatch, response, and reorganization through which well-being emerges as the experiential correlate of effective engagement rather than a stable state to be achieved. The companion preprint is available at https://doi.org/10.5281/zenodo.19371058. Keywords: state-based models, process ontology, adaptive becoming theory, becoming, well-being, dynamic systems theory, prediction error, intraindividual variability, psychopathology, enactive cognition, process-based clinical science