Complex Adaptive Systems: Going beyond complexity

Complex adaptive systems (CAS) consist of networks of heterogeneous agents that interact with one another and with the environment, giving rise to system-level patterns. A key feature of CAS is that the interactions of agents matter more than individual agents’ properties for shaping system-level outcomes, and thus “the whole is greater than the sum of its parts.” Ecosystems, human-environment systems, economic systems, social organizations, and human societies are all complex adaptive systems.

According to the Nobel laureate Murray Gell-Man and late John Holland, the founding fathers of CAS, these systems are difficult to study, and we have just begun to understand them. Since the pioneers launched the scientific inquiry into CAS at the Santa Fe Institute (SFI) in 1980s, agent-based modeling has been increasingly used to analyze these systems, but advances in the theoretical understanding of CAS have been slow.

Though I have no doubts that the science of complexity is the science of the twenty-first century, as Stephen Hawking says, it may be helpful if we shift away from the general notion of complexity, and instead focus on some of the specific properties of complex systems and emphasize the CAS approach to examine the micro-level mechanisms in these systems. (The very notion of complexity, to some skeptics, indicates something that is unknowable, contributing to suspicions about the science of complexity.)

Furthermore, as our world has grown progressively interconnected and people disconnected at the same time, a CAS approach becomes more important than ever for examining political systems, economic systems, social and cultural systems, and most important, their interactions.

This section will look at a number of complex systems and attempt to discuss some common properties and general theoretical understanding of CAS. While I may use models or point to empirical data to illustrate some cases, the writing can be at times just speculations.


Useful Readings

An inspiring introduction to CAS

Mitchell Waldrop (1992). Complexity: The Emerging Science at the Edge of Order and Chaos

A very short introduction to CAS

John Holland (2014). Complexity: A very short introduction. Oxford University Press

Classic books on CAS

Brian Arthur (1994). Increasing Returns and Path Dependence in the Economy

Kevin Kelley (1994). Out of Control

Murray Gell-Mann (1995). The Quark and the Jaguar

John Holland (1995). Hidden Order

Stuart Kauffmann (1996). At Home in the Universe

Joshua Epstein and Robert Axtell (1996). Growing Artificial Societies

Herbert Simon (1996). The Art of the Artificial

Robert Axelrod (1997). The Complexity of Cooperation

John Holland (1998). Emergence

Gary Flake (1998). The Computational Beauty of Nature

Simon Levin (1999). Fragile Dominion: Complexity and the Commons

Robert Axelrod and Michael Cohen (2000). Harnessing Complexity

Ricard Sole and Brian Goodwin (2000). Signs of Life

Albert-Laszlo Barabasi (2002). Linked

Duncan Watts (2003). Six Degrees

Stephen Strogatz (2003). Sync: The Emerging Science of Spontaneous Order

New additions

Mark Newman, Albert-Laszlo Barabasi and Duncan Watts (2006). The Structure and Dynamics of Networks

John Miller and Scott Page (2007). Complex Adaptive Systems: An Introduction to Computational Models of Social Life

Scott Page (2007). The Differences: How the Power of Diversity Creates Better Groups, Firms, Schools, and Societies

Melanie Mitchell (2009). Complexity: A Guided Tour

Ricard Sole (2011). Phase Transitions

John Holland (2012). Signals and Boundaries: Building Blocks for Complex Adaptive Systems

Hilton Root (2013). Dynamics among Nations: The Evolution of Legitimacy and Development in Modern States

Claudio Cioffi-Revilla (2014). Computation and Social Science: In Introduction to Computational Social Science

Joshua Epstein (2014). Agent_Zero: Toward Neurocognitive Foundations for Generative Social Science

Robert Axtell and Omar Guerreto (2017). Dynamics of Firms

Great real world CAS examples

Octavio Paz (1950). The Labyrinth of Solitude

Jane Jacobs (1961). The Death and Life of Great American Cities

Jane Jacobs (1969). The Economy of Cities

Thomas Schelling (1978). Micromotives and Macrobehavior

Henry Kissinger (2014). World Order

A magical realism account of CAS evolution

Gabriel García Márquez (1967). One Hundred Years of Solitude