ABSTRACT
This chapter describes the concepts necessary for the understanding of relationships between the various levels of organization, and so of description, that have developed in recent years from scientific analyses of complex physico-chemical and biological systems to wider issues in philosophy and theology. The natural and human sciences more and more give us a picture of the world as consisting of a complex hierarchy a series of levels of organization and matter in which each successive member of the series is a whole constituted of parts preceding it in the series. When the epistemological non-reducibility of properties, concepts, and explanations applicable to higher levels of complexity is well established, their employment in scientific discourse can often lead to a putative and then to an increasingly confident attribution of reality to that to which the higher-level terms refer. Reductionism has concentrated upon the relation between already established theories pertinent to different levels.
