It’s very easy to get tangled up in complexity theory. It even happens to scientists who don’t happen to be physicists. So let’s untangle things first. And then let’s see how and why complexity actually matters to people doing environmental evaluation.
The first knot we need to untie is the fact that the term “complexity” is something of a red herring. People think it means “complicated.” It doesn’t mean that at all, but something very different, highly specific, and unique. The misunderstanding this terminology generates has been so destructive even in academia that Evelyn Fox Keller (2005), a Harvard-trained physicist who works in the field of complexity and is now professor emeritus at MIT, insists on referring to the idea as self-organization rather than either complexity or emergence.
The second knot to untie is a math problem that isn’t what it seems to be. Since complexity is an actual process that can, in the simplest cases, be described by nonlinear and dynamic mathematical equations, a lot of people trying to understand complexity Google these terms and disappear down the rabbit hole of trying to figure out mathematics that even people in the field of complexity research don’t try to explain to non-specialists. Unfortunately, you simply will not be able to understand the mathematics of complexity if that’s not your field of scientific research. But fortunately, you don’t have to. Because the most significant part of complexity theory is paradigmatic. The basic nature and enormous significance of this new paradigm can absolutely be understood without math equations.
The final knot in the general understanding of complexity theory is that people often think it’s a metaphor. Even biologists and economists have insisted it’s a metaphor. It absolutely is not (Keller 2005). Complexity theory describes a real process that can be mathematically described if the complex system is a relatively simple one. Complexity scientists get quite testy when a non-complexity scientist calls it a metaphor. This particular “metaphor” knot is meaningful, though, because it tells us something important about Western culture.
The part of complexity that matters is the process of self-organization, and the phenomenon of emergence that self-organization produces. They are the “take-home message” parts of complexity, and this is particularly true for people doing environmental evaluation. Emergence should have a significant impact on the way people think about intervening in environmental processes, as it’s certainly having a major impact on the scientific field of ecology, particularly resilience ecology. Obviously, emergence needs to play an important role in the evaluation of environmental interventions too — but not in a supercomputer “identify all the separate lines of cause-and-effect” way that loops us back around to the first knot I listed, the one about thinking “complexity” simply means “complicated.” Complex ecosystems are not just unusually big wads of tangled linear cause-and-effect mechanistic processes. They are a fundamentally different type of synchronized whole-system thing.
People in Western culture have been steeped in a lifetime of schoolbooks, novels, and films that depict the universe as a mechanistic clockwork structure in which linear chains of cause-and-effect produce specific outcomes from given inputs. If you think about it, even the concept of counterfactuals sees the world this way. So when someone says “when there is a complex web of connections between individual things in a complex system, they spontaneously self-organize to produce the emergence of something entirely new” . . . well, people look at that group of words and automatically try to understand them within the one-way linear mechanistic cause-and-effect view of the world they’ve been operating on their whole lives. That’s how paradigms work: when we encounter something in the real world that doesn’t fit, the first thing we do (if we can) is try to find a way to fit that outlier thing into the existing paradigm. We just lop parts of it off and cram it right in there.
So it might be hard for you to wrap your mind around the idea that things can and do change in very important ways in a complex system without a cause-and-effect mechanism being involved at all. What happens if you add more stuff or different kinds of stuff to a complex system, for instance? Or if you remove some things instead? For instance, what if you cut down a bunch of trees in a forest, or the seeds of some invasive plants blow in? It’s hard to ask those questions without picturing a tick-tick-tick series of reactions that go from A to B to C. But of course, that’s linear and one-way and mechanistic. So no. Complexity theory says that’s not a meaningful way to think about the natural world.
Relationships — connections and communication between individuals in the system — are the key to understanding self-organization and emergence. In a complex system, individual elements connect to — relate with, or interact with — one another in multiple ways. Over time, the numbers of connections between the different elements increase: A connects to B and to C, and also to G and X and Santa Fe and purple. And every time new elements are added to the system even more new connections form. It is this rich network of connections between the elements — the ways the elements exist in communicating relationship with one another — that’s crucial in complex systems. The connections keep multiplying until eventually they reach a level of interconnectivity that triggers the process called self-organization. When that happens, the complex system spontaneously generates — on its own, without any additional outside input — a higher level of order with wholly new properties that did not exist before. This is the moment of emergence (Keller 2005, Murphy and O’Neill 1995, Picciotto 2020). Self-organization is the process by which nonlinear and nonmechanistic change emerges from a complex system.
Because something entirely new appears at the moment of emergence, it’s said the system crosses a threshold and experiences a phase change. If the connections in a complex system in which something previously emerged are disrupted enough, the system can drop below the threshold and experience a phase change back to a lower level of order. Sometimes that “lower level of order” means that a ponderosa pine forest that’s burned is replaced by a scrub oak grasslands.