Getting epiphenomena to do real work

Emergence—macro-level effects from micro-level causes—is at the heart of the conflict between reductionism and functionalism. How can there be autonomous higher level functionalities (the functionalist claim) if everything can be reduced to the fundamental forces of physics (the reductionist position)? We cut through this debate by applying a computer science lens to the way we view nature. We conclude that what functionalism calls the special sciences (sciences other than physics) do indeed study autonomous functionalities that involve real higher-level entities but that interactions among these entities is epiphenomenal in that they can always be reduced to primitive physical forces. In other words, epiphenomena, which we will identify with emergent phenomena, do real higher-level work. The proposed perspective provides a framework for understanding many thorny issues including the nature of entities, stigmergy, the evolution of complexity, phase transitions, supervenience, and downward entailment. We also discuss some practical considerations pertaining to systems of systems and the limitations of modeling.