Signals and Boundaries ─ Building Blocks for Complex Adaptive Systems

Complex adaptive systems (cas), including ecosystems, governments, biological cells,and markets, are characterized by intricate hierarchical arrangements of boundaries and signals. Inecosystems, for example, niches act as semi-permeable boundaries, and smells and visual patternsserve as signals; governments have departmental hierarchies with memoranda acting as signals; and soit is with other cas. Despite a wealth of data and descriptions concerning different cas, thereremain many unanswered questions about "steering" these systems. In Signals andBoundaries, John Holland argues that understanding the origin of the intricatesignal/border hierarchies of these systems is the key to answering such questions. He develops anoverarching framework for comparing and steering cas through the mechanisms that generate theirsignal/boundary hierarchies.

Holland lays out a path for developing the frameworkthat emphasizes agents, niches, theory, and mathematical models. He discusses, among other topics,theory construction; signal-processing agents; networks as representations of signal/boundaryinteraction; adaptation; recombination and reproduction; the use of tagged urn models (adapted fromelementary probability theory) to represent boundary hierarchies; finitely generated systems as away to tie the models examined into a single framework; the framework itself, illustrated by asimple finitely generated version of the development of a multi-celled organism; and Markovprocesses.