The re-emergence of emergence, and the causal role of synergy in emergent evolution

Despite its current popularity, "emergence" is a concept with a venerable history and an elusive, ambiguous standing in contemporary evolutionary theory. This paper briefly recounts the history of the term and details some of its current usages. Not only are there radically varying interpretations about how to define emergence but "reductionist" and "holistic" theorists hold very different views about the issue of causation. However, these two seemingly polar positions are not irreconcilable. Reductionism, or detailed analysis of the parts and their interactions, is essential for answering the "how" question in evolution-how does a complex living system work? But holism is equally necessary for answering the "why" question-why did a particular arrangement of parts evolve? In order to answer the "why" question, a broader, multi-leveled paradigm is required. The reductionist approach to explaining emergent complexity has entailed a search for underlying "laws of emergence." In contrast, the "Synergism Hypothesis" focuses on the "economics"-the functional effects produced by emergent wholes and their selective consequences in evolutionary change. This paper also argues that emergent phenomena represent, in effect, a subset of a larger universe of cooperative, synergistic effects in the natural world.