DOI

Summary
This work, which has been described as one of the most insightful books into the nature of living entities, introduced, in 1956, a new set of terms for discussing properties of systems, both biological and mechanical, pulling together related fields in information theory and relating them to the (as of then) mostly theoretical field of cybernetics, involving control and communication in both animals and machines. As a science, cybernetics was conceived as being cross-disciplinary involving elements of physics, chemistry and biology. The book was a forerunner in providing biological applications of general theories of systems.
Its author, W. Ross Ashby, who was knowledgeable in pathology, bacteriology and biochemistry, was first and foremost a psychiatrist, the director of a psychiatric hospital in Gloucester. Ashby was, in fact, fascinated by the underlying organization of the human nervous system to such a point that he eventually attempted to design a “homeostatic” machine that could imitate the adaptive behavior of the human brain. His ideas on adaptive systems were based on an epistemological approach through analogy, which described the mental phenomenon of “adaptation” as an equivalent to a physical/mechanical process of “equilibrium”, which could thus be analyzed in a similar manner to mechanical processes.

Relevance for Complex Systems Knowledge
Ashby introduced the concept of acquiring knowledge through the selection of random, disorganized information, which if applied to a machine might endow it with the capacity to develop novel strategies beyond those created by its designer, setting forth a concept which he called the “law of requisite variety”, involving variety, regulation and control.His creation of a General Theory of Adaptive Systems anticipated many concepts used today in A.I.
Ashby was concerned with organized complexity, including brains, organisms, and societies, and his approach to creating complex systems was unusual, especially for that time: rather than attempting to build more complex structures by assembling components, Ashby chose to look for constraints or rules of interaction which reduce the maximum possible variety to the variety actually observed.

Point of Strength
being more general or abstract than the theories in most disciplines, his interdisciplinary theories span biology, psychology, and economics and more general fields such as philosophy or mathematics. It is remarkable that Ashby was able to formulate theories that work for so many domains; their formal structures can be applied in many fields.