Complex Systems

Imagine you’re a scientist who studies ants. If you grabbed a magnifying glass and examined an ant’s daily routine, you would conclude that ants are simple creatures. Each day, an ant will decide on a task to fill its time. Whether it be foraging, digging holes, rolling dirt up hills, or any other ant antics they can think of, this individual behavior is often predictable and easy to understand. But what happens when ants interact with each other?

After a few weeks of examining an ant colony, you would be shocked about the efficiency, teamwork, and complex structures that emerge from ants’ collective effort. Ant colonies are capable of performing incredibly complex tasks, ranging from building bridges to farming aphids as livestock. These behaviors are so complex that if you looked at the colony collectively rather than individually, you would see that it characterizes a living organism. Like a living organism, ant colonies have goals, adapt, expand, and have a life cycle. However, there is no “brain” behind this “living system”¹.  While it may be hard to imagine, no ant governing body masterminds all of the colony’s actions. By themselves, ants aren’t very smart. They’re only capable of doing very simple tasks. Despite their tiny brains, each day an ant makes a personal decision about what they are going to work on, and what emerges is a living system capable of tasks any individual ant couldn’t even dream of. How does this happen?

Complex systems are networks of small parts which interact to produce something that could not be predicted by analyzing any one individual part by itself. The general idea of a complex system is encapsulated by the common saying “the whole is greater than the sum of its parts”. While they are typically difficult to predict, the products of a complex system often result in broader trends that are observable over time.

Typically, these complex systems are built with 3 building blocks:²

1. They are composed of a number of different actors who make their own decisions.
2. These agents interact with each other.
3. The system produces something greater than the sum of its parts.

While this may seem abstract, complex systems are everywhere if you know how to find them. Because they are so prevalent, complexity has gone from a niche academic idea to a key facet of several academic disciplines. The academic reach of complex systems is also vast: economics, education, biology, meteorology, urban planning, physics, mathematics, and many other fields have integrated its models. From something as small as your immune system to something as global as capital markets, complex systems are constantly operating around the world.