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

Evolution continually innovates, but at each level it conserves the elements that are recombined to yield the innovations.

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.

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.

nonlinear interactions almost always make the behavior of the aggregate more complicated than would be predicted by summing or averaging.

The measure of performance of any given agent is the amount of money it accumulates through its actions.

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.