This paper deals with the questions of emergence and complex (mental and social) systems and with downward determination from the viewpoint of perspectival realism. These are issues concerning the foundations of the human sciences, generally speaking, and particularly psychology and sociology. A criterion is put forward, which distinguish metaphysicalfrom ontological (conceptual) problems, and the notions of complex, hierarchic system and causation that would be suitable for those that defend emergence and perspectivist foundations of the human sciences are discussed.
Emergence; Downward causation; Complex systems; Perspectivist realism