Vanderbilt Law Review


J. B. Ruhl

First Page



Why does law change, and how does that process unfold? In this Article, Professor Ruhl examines those questions using tools from the emerging field of Complexity Theory. Complexity Theory involves the study of change in dynamical systems. Its findings of unpredictable change in a variety of natural and social settings have profoundly effected the theoretical foundations of many fields of study. In particular, Complexity Theory has revisited the Darwinist theory of biological evolution and used it as a platform for developing a general theory of system evolution that focuses on the concept of fitness landscapes. The fitness, or sustainability, of each system component-in the case of biological evolution, each species-depends on the possible combinations of variables that define the component (for example, speed, weight, and strength). Those combinations and their associated fitness levels form a landscape of possibilities over which the system component can move to attempt to improve its fitness. Moreover, because the fitness of each combination will depend in part on the behavior of other system components, the fitness landscapes of all system components are coupled such that as one component evolves to different levels on its landscape, the landscapes of other components may be altered. By developing and studying the model of coupled fitness landscapes, Complexity Theory has provided new insights into the why and how of evolution in a variety of contexts.

The history and process of change in law exhibits many of the traits of coupled fitness landscapes. This Article begins by illustrating how legal theory has embraced Darwinism as one of its models of legal change, and thus how legal theory is ripe to integrate what Complexity Theory has to offer that model. Using examples from environmental law, the Article unfolds the analogy between Complexity Theory's general fitness landscape model and the record of legal change. Finally, the Article develops the general principles of what the fitness landscape model suggests will be the most fit sociolegal systems and compares them to the present condition of the modern administrative state, concluding that significant and fundamental reforms are necessary in order to take full advantage of the fitness traits our constitutional system offers.