Emergence is a concept which has been the subject of resurgent interest in recent years. The term is often used to describe the appearance of new macro-level properties or capabilities, which are not manifest in the individual micro-level components. Equally, it is associated with irreducibility of explanation, novelty and downward causation. Despite a long history, during which the concept has been adopted by different disciplines, there is little agreement on the real nature of emergence. This, I claim, is due to different philosophical and disciplinary perspectives as well as some lack of conceptual clarity. The aim of this thesis is not to resolve the extremely hard problem of what emergence is; rather it is to provide clearer insight i...