# John Henry Holland

John Henry Holland (2 February 1929 - 9 August 2015) was an American scientist and Professor of Psychology and Professor of Electrical Engineering and Computer Science at the University of Michigan, Ann Arbor. He was a pioneer in complex systems and nonlinear science. He is known as the father of genetic algorithms.

## Quotes
### Hidden Order - How Adaptation Builds Complexity (1995)

* "Doing science," particularly the synthesis of disparate ideas, is not as arcane as it is often made out to be. Discipline and taste play a vital role, but the activity is familiar to anyone who has made some effort to be creative.
** Preface, p. xix

#### Ch 1. Basic Elements

* Even though these complex systems differ in detail, the question of coherence under change is the central enigma for each.
** p. 4
* With theory, we can separate fundamental characteristics from fascinating idiosyncrasies and incidental features. Theory supplies landmarks and guideposts, and we begin to know what to observe and where to act.
** p. 5
* If we are to understand the interactions of a large number of agents, we must first be able to describe the capabilities of individual agents.
** p. 7
* "nonlinear interactions almost always make the behavior of the aggregate more complicated than would be predicted by summing or averaging."
** p. 23
* The multiplier effect is a major feature of networks and flows. It arises regardless of the particular nature of the resource, be it goods, money, or messages.
** p. 25
* The recycling of resource by the aggregate behavior of a diverse array of agents is much more than the sum of the individual actions.
** p. 31
* This use of building blocks to generate internal models is a pervasive feature of complex adaptive systems.
** p. 37

#### Ch 2. Adaptive Systems

* If there is to be a competition, there must be some basis for resolving it. It is also clear that the competition should be experienced based.
** , p. 53
* When a new building block is discovered, the result is usually a range of innovations.
** p. 62
* Particular individuals do not recur, but their building blocks do.
** p. 79
* Evolution continually innovates, but at each level it conserves the elements that are recombined to yield the innovations.
** p. 80
* The measure of performance of any given agent is the amount of money it accumulates through its actions.
** p. 86

#### Ch 3. Echoing Emergence

* Looking back to data, we can see if the consequences are plausible; looking forward to theory, we can see if general principles are suggested.
** p. 97
* There is more of a mystery to the origin of the pin factory that Adam Smith (1776) discusses in his Wealth of Nations than is generally realized.
** p. 97
* Unwrapping occurs when the "solution" is explicitly built into the program from the start.
** p. 137

#### Ch 4. Simulating Echo

* Model building is the art of selecting those aspects of a process that are relevant to the question being asked. As with any art, this selection is guided by taste, elegance, and metaphor; it is a matter of induction, rather than deduction. High science depends on this art.
** p. 146
* The end point, a cas simulation with a realistic interface, is highly desirable, because it enables an ecologist, or economist, or politician to try out alternatives that could not possibly tried in real systems.
** p. 158

### About Henry Holland

* Holland's and Kauffman's work, together with Dawkins' simulations of evolution and Varela's models of autopoietic systems, provide essential inspiration for the new discipline of artificial life, This approach, initiated by Chris Langton (1989, 1992), tries to develop technological systems (computer programs and autonomous robots) that exhibit lifelike properties, such as reproduction, sexuality, swarming, and co-evolution.
** Francis Heylighen (1996) "Complex Adaptive Systems" on: Principia Cybernetica Web, Nov 12, 1996