Across disciplines as distant as slime-mold biology, cognitive psychology, evolutionaryecology, organizational theory, and software architecture, a common pattern recurs: when asystem whose components are coupled and heterogeneously plastic is subjected tosustained environmental constraint, those components undergo functional differentiation.Yet the pattern has no name, and each discipline attributes the resulting phenomena tocomponent-level properties — "cognitive bias," "individual incompetence," "speciesadaptation," "technical debt" — rather than recognizing them as instances of a singlefield-level process. This paper proposes the Differentiation Pressure Principle (DPP):functional differentiation is the generic response of coupled, plastic, heterogeneous systemsto back-pressure, and causal attribution to individual components is a category error. Wepresent evidence across six tiers of systems — colonial organisms without nervoussystems, social insect colonies, non-human vertebrate collectives, human cognition,multi-species ecological networks, and human-engineered systems — and show that theprinciple operates in a scale-free, nested manner. We further distinguish two phases:healthy differentiation, in which niche turnover is maintained through natural degradation ofcomponents, and pathological frozen differentiation, in which institutional or structuralmechanisms arrest turnover and the system loses adaptive capacity. Finally, we propose asa formal conjecture that the dynamics of DPP correspond to symmetry breaking underconstraint in coupled systems, with the Kuramoto synchronization model and theLandau-Stuart equation providing candidate formalisms for specific coupling types. Theprinciple does not discover new phenomena; it re-identifies known phenomena across tendomains as instances of a single process, and in doing so, dissolves a class of causalattributions that have long been mistaken for explanations.
Franny Philos Sophai (Fri,) studied this question.