sentences:  They have been developing a new theory complex, which came to be referred to as actor-system dynamics (ASD), a new social systems theory, substantially different from Parson's systems theory and the systems theory later developed by Niklas Luhmann.This approach brought human agents in a natural and coherent way into system modelling.It saw agents (individuals and collectives) in their strategems and ploys as constrained as well as enabled by system structures, but also as forces structuring and restructuring systems and, in some instances, creating entirely new ones.