Downward causation is found in two-level and multi-level systems with complex behaviour generated by many components interacting. The term was coined by the social psychologist and philosopher Donald T. campbell, who asked the question: if many small-scale interactions can create emergent large-scale patterns, can large-scale patterns reinfluence the small-scale interactions that generated them? This has led to many further questions, among them: does the cell as a system reorganize the biochemical processes inside it in a new way? do psychosomatic illnesses exist? is the so-called hermeneutic circle real? should we interpret these higher-level phenomena as indicating a new ontological layer with its own units and laws? are there special substances of life, mind and meaning? can life change biochemical laws? can mind change the body? The chapters in this comprehensive book address these questions from the viewpoints of different disciplines. Contributors are experts in the fields of information and media science, philosophy, anthropology, mathematics, physics, psychology, history and social conditions, education, logic and the philosophy of science, systems science,comparative literature and Nordic languages and literature at universities in Denmark, the United States, Spain, and Brazil.