:(vii) The next level is the "human" level, that is of the individual human being considered as a system... - Kenneth E. Boulding

The main key to the economics of the postwar world is a simple truism — that the rate of accumulation is equal to the rate of production less the rate of consumption. This is the "Bathtub Theorem." Production may be likened to the flow of water from the faucet, consumption to the flow down the drain. The difference between these two flows is the rate at which the water in the bathtub - the total stockpile of all goods - is accumulating.
War drains the economic bathtub in a great waste of consumption. The first problem of reconstruction is to rebuild the stockpile. It can be rebuilt only by widening the gap between production and consumption, or, in the case of a single country, by importing more than is exported. It is difficult for a ravaged country to increase either its production or its net imports. Unless it can obtain outside help, therefore, it must suffer a drastic restriction of consumption. Frequently the only way consumption can be restricted is by inflation. Here, therefore, is the key to the most fundamental problems of reconstruction.

One can even go beyond know-what into know-whether. This involves the evaluative structure of the human mind which enables us to make decisions and choices among different images of the future. Human behavior cannot be explained without this further development in the hierarchy that starts with simple information. This actually goes back a long way in evolution. Even the amoeba knows whether to absorb a piece of grit or a piece of food.

In spite of the moderate usefulness of what the economist has to say on this subject... there is a cry for a cultural anthropologist or even a psychologist when the economist runs into sacred cows, extended families, traditional motivations, levels of achievement, and social morale, all of which may be more important to economic development than any of the traditional economic variables. We still await a true synthesis of the insights of economics with those of other social sciences in the area