On System Complexity: Identification, Measurement, and Management

The notion of system complexity is much like St. Augustine’s description of time: “What then is time [complexity]? If no one asks me, I know; if I wish to explain it to one that asks, I know not.” There seem to be fairly well-developed, intuitive ideas about what constitutes a complex system, but attempts to axiomatize and formalize this sense of the complex all leave a vague, uneasy feeling of basic incompleteness, and a sense of failure to grasp important aspects of the essential nature of the problem. In this chapter we examine some of the root causes of these failures and outline a framework for the consideration of complexity that provides a starting point for the development of operational procedures in the identification, characterization, and management of complex processes. In the process of developing this framework for speculation, it is necessary to consider a variety of system-theoretic concepts closely allied to the notion of complexity: hierarchies, adaptation, bifurcation, self-organization, and reductionism, to name but a few. The picture that emerges is that of complexity as a latent or implicate property of a system, a property made explicit only through the interaction of the given system with another. Just as in baseball where some pitches are balls and some are strikes, but “they ain’t nothin” until the umpire calls them, complexity cannot be thought of as an intrinsic property of an isolated (closed) system; it is only made manifest by the interaction of the system with another, usually in the process of measurement and/or control.