WORK
Signals and Boundaries
Holland's 2012 MIT Press final major work — completed at eighty-three — refining the building blocks framework around the claim that complex adaptive behavior is determined by the signals that flow through the system and the boundaries that constrain those flows.
Signals and Boundaries, subtitled 'Building Blocks for Complex Adaptive Systems,' was Holland's last major statement of the framework he had spent sixty years developing. The book's central argument was that the behavior of complex adaptive systems is determined by two things: the signals that flow through the system and the boundaries that constrain those flows. Signals carry information. Boundaries create structure. Without signals, the system is inert. Without boundaries, the system is noise. The adaptive system is the one that maintains the right signals flowing through the right boundaries — adjusting both continuously as conditions change. The signals-and-boundaries framework is a refinement of the earlier seven-properties taxonomy, emphasizing the dynamic interplay between information flow and structural constraint as the engine of adaptive behavior.
