John Henry Holland

"Particular individuals do not recur, but their building blocks do."

"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."

"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 mat…"

"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 ma…"

"Unwrapping occurs when the "solution" is explicitly built into the program from the start."

"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."

"Looking back to data, we can see if the consequences are plausible; looking forward to theory, we can see if general principles are suggested."

"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 whe…"