"An international system consists of a group of interacting behavior units called "nations" or "countries," to which may sometimes be added certain supra-national organizations, such as the United Nations. Each of the behavior units in the system can be described in terms of a set of "relevant variables." Just what is relevant and what is not is a matter of judgment of the system-builder, but we think of such things as states of war or peace, degrees of hostility or friendliness, alliance or enmity, arms budgets, geographic extent, friendly or hostile communications, and so on. Having defined our variables, we can then proceed to postulate certain relationships between them, sufficient to define a path for all the variables through time. Thus we might suppose, with Lewis Richardson that the rate of change of hostility of one nation toward a second depends on the level of hostility in the second and that the rate of change of hostility of the second toward the first depends on the level of hostility of the first. Then, if we start from given levels of hostility in each nation, these equations are sufficient to spell out what happens to these levels in succeeding time periods."

“It is much more accurate to identify the factors of production as know-how , energy, and materials, for, as we have seen, all processes of production involve the direction of energy by some know-how structure toward the selection, transportation, and transformation of materials into the product”

“Equilibrium is a figment of the human imagination.”

“One advantage of exhibiting a hierarchy of systems in this way is that it gives us some idea of the present gaps in both theoretical and empirical knowledge. Adequate theoretical models extend up to about the fourth level, and not much beyond. Empirical knowledge is deficient at practically all levels.”

“The World is a very complex system. It is easy to have too simple a view of it, and it is easy to do harm and to make things worse under the impulse to do good and make things better.”

“The very act of thinking about power in our lives and experiences creates a process of revelation and self-analysis that may even make us look at ourselves in a new light... thinking about power and its complex manifestations may not simply lead to a better understanding of the abstract complexities of society, but may have an effect on one‟s own image and identity. Perhaps a warning label should be placed on the cover...”

“Without the heroic, man has no meaning; without the economic, he has no sense. Economic man is most likely to be economic woman — a good wife, pulling the coat tails of her heroic husband, checking his extravagances of speech and action with words of caution and good sense. But without the heroic coat tails to pull, life for both of them would be dull and savorless indeed.”