Wants are constantly shifting; different kinds of goods are compared in man's thought and arranged on a scale at every moment according to their felt utility. An increase in the amount of a good will drop the marginal utility of the added portions down the scale of usefulness for the next moment. When we rise in the morning, we want our breakfast; the breakfast eaten, another breakfast does not appeal to us. Our tasks done, we take a boat-ride or go golfing; then, appetite returning, we are tempted to our dinner. And thus from hour to hour wants are gratified, are altered and are shifted, until, wearied with the day's labor and pastimes, we go to rest. In a well-ordered life, in an advanced economic society, the means for gratifying our wants as they arise are provided in advance. The changing series of desires is met by a changing series of goods. Life has been defined as a constant adjustment of inner relations to outer conditions. Economic life is therefore like physical life, a constant adjustment; and this adjustment of goods but reflects the shifting and adjustment of feelings. [Sidenote: Choice is constantly shifting] 6. _The substitution of goods in men's thought is the shifting of the choice from a good that does not give the highest gratification economically possible at the time, to another good that does._ The shifting that takes place on the scale of gratification makes it necessary for man to shift constantly his choice of goods. This again is the problem of "economy." Waste results when goods continue to be used to secure a lower degree of gratification, if they might be used to secure a higher. The change of choice may be because of a change in the man, or because of a change in the quality or the quantity of the goods; or because of a change in the ratio at which the goods can be secured. § II. DEMAND FOR GOODS GROWS OUT OF SUBJECTIVE COMPARISONS [Sidenote: Desire may become demand] 1. _Demand is desire for goods united with the power to give something in exchange._ An example frequently given to show the difference between desire and demand is the hungry boy looking longingly at the sweetmeats in the confectioner's window. He represents desire, but not until the kind-hearted gentleman gives him a nickel does he represent effective demand. Desire, therefore, must be united with power to give something in exchange before it can be called demand. It must be for something that is attainable; yearning for something beyond reach, sighing for the moon, is desire that never can become effective demand. [Sidenote: Demand the Social expression of shifting choice]