ABSTRACT
This chapter is concerned with the "prehistory" of quantitative forecasting, and in the next with the form it has taken in short-term economic forecasting. It indicates what role quantitative forecasting plays when longer periods, say, fifteen to twenty-five years, are considered: that is what interests the author most of all, the horizon discussed in terms of possible futures in the surmising forum. Quantification is useful for exposition but even more useful in forecasting. The forecaster must beware of letting his audience think that a growth is a "natural datum" when it is in no way guaranteed. While forecasters have very different opinions about future growth rates, they do at least agree that the future they forecast is not inevitable. The supposition that obstacles to growth increase in proportion to growth actually achieved is intuitive. Mathematical minds applying themselves to social phenomena should come up with important results. A mathematical formula is never more than a precise statement.
