Economics, we learn in the history of thought, only became a science by escaping from the casuistry and moralizing of medieval thought.

The right to have children should be a marketable commodity, bought and traded by individuals but absolutely limited by the state.

One of the most important skills of the economist, therefore, is that of simplification of the model. Two important methods of simplification have been developed by economists. One is the method of partial equilibrium analysis (or microeconomics), generally associated with the name of Alfred Marshall and the other is the method of aggregation (or macro-economics), associated with the name of John Maynard Keynes.

Nothing fails like success, because we do not learn anything from it. We only learn from failure, but we do not always learn the right things from failure. If there is a failure of expectations, that is, if the messages that we receive are not the same as those we expected, we can make three possible inferences.

The social dynamics of human history, even more than that of biological evolution, illustrate the fundamental principle of ecological evolution - that everything depends on everything else. The nine elements that we have described in societal evolution of the three families of phenotypes - the phyla of things, organizations and people, the genetic bases in knowledge operating through energy and materials to produce phenotypes, and the three bonding relations of threat, integration and exchange - all interact on each other.

Communication can only take place among equals.

The illusion that consumption - and its correlative, income - is desirable probably stems from too great preoccupation with what Knight calls "one-use goods," such as food and fuel, where the utilization and consumption of the good are tightly bound together in a single act or event. ... any economy in the consumption of fuel that enables us to maintain warmth or to generate power with lessened consumption again leaves us better off. ... there is no great value in consumption itself.