Stage theory, in the context of systems thinking and ecological understanding, refers to the conceptual framework that asserts developmental processes occur in discrete, sequential phases. Each stage represents a qualitatively distinct level of complexity, integration, and functionality. Within living systems, including human growth, cultural evolution, and organizational practices, stage theories propose that progression is not merely linear but involves nonlinear leaps and transformations, each step building upon the foundations of the previous ones. This perspective entails recognition of both the inherent potentialities and limitations encoded within each stage, as well as the dynamic interplay of interactions that drive the transition between them. Emphasizing the relational nature of development, stage theories underscore that the maturation of any system is embedded within and responsive to the broader context of its environment, continuously co-evolving within a web of interdependencies.

See also: spiral dynamics, systems theory, complex system, relationship