Signals and Boundaries

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. In ecosystems, for example, niches act as semi-permeable boundaries, and smells and visual patterns serve as signals; governments have departmental hierarchies with memoranda acting as signals; and so it is with other cas. Despite a wealth of data and descriptions concerning different cas, there remain many unanswered questions about “steering” these systems. In Signals and Boundaries, John Holland argues that understanding the origin of the intricate signal/border hierarchies of these systems is the key to answering such questions. He develops an overarching framework for comparing and steering cas through the mechanisms that generate their signal/boundary hierarchies.

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

Table of Contents

1 The Roles of Signals and Boundaries 1
2 Theory and Models: General Principles 35
3 Agents and Signal Processing 57
4 Networks and Flows 85
5 Adaptation 99
6 Recombination and Reproduction 117
7 Urn Models of Boundaries 131
8 Boundary Hierarchies 145
9 The Evolution of Niches — A First Look 159
10 Language: Grammars and Niches 181
11 Grammars as Finitely Generated Systems 205
12 An Overarching Signal/Boundary Framework 217
13 A Dynamic Generated System Model of Ontogeny 229
14 A Complete Dynamic Generated System for Signal/Boundary Studies 245
15 Mathematical Models of Generated Structures 265
16 A Short Version of the Whole 281