There are certain primary wants or desires which must be satisfied at any cost, such as the desire for a sufficient quantity of food to preserve life or for enough clothing to keep us from freezing to death. As soon as these absolute wants are satisfied they are followed by other wants, - as, for example, when we have had sufficient food to keep us alive we then desire enough to make us feel comfortable, or we desire variety, of which the man who is suffering the pangs of hunger does not think. Similarly with clothing, it is only after we have sufficient to keep us warm that we feel the need of having it conform to the prevailing fashion.

The principle is of general application. As soon as our most urgent needs are taken care of, other needs differing in degree and in kind spring into consciousness to take their places. While individual wants may be satisfied, all man's wants here below are never satisfied. It is because of his desire to satisfy his wants that man is driven to economic activity. And his activities in turn serve to arouse in him new wants which demand satisfaction.