Two Concepts of Emergence

Abstract: The correlated terms "emergence" and "reduction" are used in several ways in contemporary discussions ranging from complex systems theory to philosophy of mind, a fact that engenders confusion or talking at cross purposes. I try to bring greater clarity to this discussion by reflecting on John Conway's cellular automaton The Game of Life and simple variations on it. We may think of such variants as toy models of our own world that, owing to their simplicity, enable us to see quite clearly, in general terms, two importantly distinct ways (“weak” and “strong”) in which organized macroscopic phenomena might emerge from underlying microphysical processes. Strong emergence is of greater significance to metaphysics and philosophy of mind; it is also commonly deemed implausible. I close by suggesting that typical reasons for this evidential judgement are unconvincing.