The two visions draw lessons from theory differently, and are associated with quite different research programs, especially as they relate to policy. The equilibrium vision sees formal theory as providing a necessary blueprint for policy. Franklin Fisher (2011) nicely captures this view. He writes,

“It is not an overstatement to say that they (the general equilibrium welfare theorems) are the underpinnings of Western capitalism… So elegant and powerful are these results (G.E.’s exploration and proofs of existence, uniqueness, and optimality) that most economists base their conclusions upon them and work in an equilibrium framework.”

In the equilibrium vision, without formal theory, policy has no scientific foundation. It takes the position: Better to have an inadequate formal theory than no formal theory at all.

The complexity vision sees developing a useful tractable formal general theory as currently far beyond our capabilities and instead focuses on gaining partial insights into the complex dynamics of the economy in whatever way it can – agent based models, simulations and general exploration of non-linear dynamic models. Since formal dynamics is analytically so difficult, the complexity vision is content with informal theory especially when talking about the aggregate economy. It takes the position: When guiding policy it is better to recognize that we have no directly useful formal theory than to confine policy analysis to an inadequate formal theory. Within the complexity vision ultimately, because the formal specification of the economy is so beyond our current analytic capabilities, even the best economic policy is based on heuristics, not scientific theory, and thus, in a formal scientific sense, is ungrounded. Policy advice should not be presented to policy makers as otherwise.

The complexity approach to policy holds that, because of the complexity of economic theory’s relationship to the real world, policy discussions are best separated from scientific discussions. Policy discussions should be based not directly on formal scientific theory, but, instead, on educated common sense – a wide ranging knowledge of economic scholarship that includes a good understanding of where researchers are in advancing formal theory, a good understanding of the history and institutions of the economy, a detailed familiarity with empirical data about the economy, and a philosophical understanding of the role that ethical views play in arriving at policy advice. Good policy is based on far more than just economic science.

The complexity approach divides economic analysis into two separable fields: science, whose goal is to discover the truth, and applied policy, whose goal is to solve real-world problems. The two fields are separated by a firewall to reduce the possibility of policy views influencing scientific judgments.[1] The goal is to allow specialization and gains from trade. The same economist could do both science and policy, but the two activities would use different methodologies, and would require different skill sets.

While the complexity methodology downplays the importance of formal theory in directly guiding policy, it is not against formal deductive theory, abstract mathematics, or sophisticated empirical research. But the goal of that theoretical research is a scientific goal – to better understand the economy; the goal is not to guide policy (although some policy guidance might follow as an unintended consequence). Thus, the complexity vision’s scientific research agenda is consistent with a vigorous and highly abstract theoretical and empirical research agenda that, if anything, because its focus on complex dynamics, is even more mathematically and statistically complex than the current research agenda associated with the equilibrium vision. In that sense the complexity methodology is quite different from the critical realist methodology espoused by heterodox critics of economics such as Tony Lawson.

Critical realists criticize equilibrium methodology for its emphasis on abstract mathematics; complexity theory embraces mathematics. Complexity economists criticize the equilibrium methodology for the way it uses theory in thinking about policy, not for its use of mathematics. Whereas the equilibrium methodology treats formal theoretical results as central to its applied policy research, the complexity methodology uses formal theory more as a fable or heuristic, which may or may not be relevant for policy. Within the complexity vision, formal theory is best thought of as a thought experiment that can be useful both for thinking creatively about policy problems and for preventing logical mistakes in reasoning. But, because the theory is only tenuously related to the real world economy the theory is meant to capture, the results of formal theory are not to be thought of as a blueprint for policy.

The distinction among the equilibrium, complexity and critical realist/heterodox views of the equilibrium methodology can be seen in reference to the well-known “searching for the keys under the lamppost joke.” The standard interpretation of the joke embodies the critical realist view. It is that economic theorists are out there in La-la-land, doing highly abstract economic research unrelated to the real world.

“Isn’t it stupid – searching where you haven’t lost the keys just because that’s where the light is?”

“Isn’t it stupid – working on models that you know are so far from reality that they can’t possibly describe reality: representative agent super rational choice models, when it’s obvious that the action is in interactive effects; Isn’t it stupid to work with strict rationality models, when it’s obvious that people are at best boundedly rational?”

From a complexity standpoint, a research strategy of “searching where the light is” is far from stupid. Where else but where the light is can one do formal theory? Where the complexity vision has a problem with the current equilibrium methodology is with its attempt to apply the abstract theory, developed where the light is, directly to policy. That’s the equivalent to searching for the keys where you did not lose them, and deserves the critical realists’ scorn. The complexity vision sees the goal of theorists searching in the light to be discovering potential patterns that help them understand the economy. While the goal is not to guide policy the discovered patterns might be helpful to applied policy researchers exploring in the dark. Theorists are developing an abstract knowledge of economic topographies, exploring abstract topographies where there are the equivalent of rocky cliffs, where there are smooth deltas, rolling hills, and where sudden storms changed the topography quickly, as a small creek becomes a raging river. This leads to a second role for theorists—to develop creative abstract policy solutions to deal with different topographies. These abstract solutions may or may not be transferrable to the real world. But the exploration can suggest other solutions that might work. The goal of this part of policy theorizing is creative design of policy. **read more**