Abstract

A crucial question for both philosophy and for science concerns the kind of relationship that obtains between entities—objects, properties, states, processes, kinds and so on—that exist at apparently higher and lower ‘levels’ of reality. According to reductionism, seeming higher-level entities can in fact be fully accounted for by more fundamental, lower-level entities. Conversely, emergentists of various stripes hold that whilst higher-level entities depend in some important sense on lower-level entities, they are nevertheless irreducible to them. This introductory paper outlines the context of the debate between emergentists and reductionists; offers a broad characterisation of ‘strong’ or ontological emergence, and provides summaries of each of the papers to come in this special issue.