Complexity Theory
In The Oxford Handbook of the Philosophy of Science, edited by Paul Humphreys, 2016.
Abstract:
Complexity theory attempts to explain, at the most general possible level, the interesting behaviors of complex systems. Two such behaviors are the emergence of simple or stable high-level behavior from relatively complex low-level behavior, and the emergence of sophisticated high-level behavior from relatively simple low-level behavior; they are often found nested in the same system.
Concerning the emergence of simplicity, this essay examines Herbert Simon's explanation from near-decomposability and a stochastic explanation that generalizes the approach of statistical physics. A more general notion of an abstract difference-making structure is introduced with examples, and a discussion of evolvability follows.
Concerning the emergence of sophistication, this essay focuses on, first, the energetics approach associated with dissipative structures and the fourth law of thermodynamics
, and second, the notion of a complex adaptive system
.