 (ii) Self-organization: Process metaphysics traditionally has been motivated by the fact that it seems to give the best explanation of the phenomena of diachronic emergence, originally understood as an integral feature of evolution. Since the development of scientific theories of “self-organization,” “chaos,” and “complexity” have begun to alter our understanding of evolutionary change, there is a new need for a metaphysics that can accommodate all sorts of phenomena where dynamic organizations exert causal constraints. While older, speculative, process metaphysics embraced the idea of purposes and creativity in nature, and allowed for the explanatory category of a ‘self-realizing’ or ‘self-engendering’ entity (in various terminological guises), present-day analytical processists confine themselves to arguing that “downward causation” becomes perfectly intelligible once physicalism has been divorced from the assumptions of the substance paradigm, and especially from the principle that causal powers cannot be attributed to dynamic  organizations.[21]