The Structure of an Economy

Any economy is a segment or subset of a larger system. The United States economy is a segment of the world economy, the world economy is a segment of the total system of Planet Earth. Any system, however large or however small, has two aspects involved in its description: one, its structure in space at a moment of time; the other, its structure in space and time. First we have to describe the system at a moment of time. This might be called a flashlight photograph or a single frame of a movie. The world globe provides a good example. The globe will show coastlines and oceans. It may also show national boundaries, mountains, plains, rivers, lakes and so on. Obviously what can be put on a globe a foot in diameter is a very small part of the reality of the world. Nevertheless it is a place to begin. Even on a small globe we can plot the density of the human population, the broad classification of the uses of land — forests, agriculture and so on — and perhaps give some indication of where the major industries are located. On a one-foot globe we obviously cannot plot the position of every one of the world’s 5.2 billion human inhabitants. To do that we would have to have a globe about a mile high, on which each human being could be plotted as a point about one-thousandth of an inch in diameter, a house about one-tenth of an inch in diameter.