Evolution is defined as the continuous complexification of interacting (energy-matter-) entities: matter-bound processes of circular causality, i.e., of shaping, interfacing, and countershaping. These processes are ruled in living systems by the principle of interactive or circular autonomy, realizing endo-exo interfaces by a well-integrated neuro-psychic domain constituted by corresponding membrane-related genotypic, metabolic, ionic, and neuro-synaptic levels of self-organization. This domain processes "best matching" interface representations. The polarity between res extensa and res cogitans is related to two circular functions of the neuro-psychic domain in opposite time-directions: future-directed projection and past-directed accomodation.