3. _Progress takes place where new wealth gratifies marginal wants as intense as those of the preceding period._ If the utility of every kind of goods decreased uniformly as wealth increased, desire would steadily decline in intensity. But old wants vary and new wants develop with prosperity. Desire grows by what it feeds on. Ambition passes on to other and higher peaks. The direction of the individual man's life thus is determined by the expenditure of his increasing income. Wealth makes possible a new adjustment of life, a new character, both in the individual and in the society. [Sidenote: Wealth a means to living] The thought that needs emphasis in this connection is that, while production and consumption are separable in thought and distinguishable in practice, they are not opposed in their ultimate purpose. The highest fruits of production are in the lessons of sacrifice and discipline, and in its opportunities for experience and self-expression. The best result of the consumption of wealth is not the gratification of appetite, but the strengthening of the spiritual forces within men. The world is to rise to a higher social stage not by banishing labor and by multiplying sensual enjoyments of the commoner sort. Wealth, even in an economic view, is not the end of life, but merely the means to its realization. [Sidenote: Variety and harmony in the choice of goods] 4. _Enjoyment is increased by a proper variety and harmony of goods._ As the old kinds of goods increase in amount and fall in value, there must be a substitution of new goods. An element added to the dress or to the diet heightens greatly the total gratification. The result is a unit. Think of a dinner without butter, or a cranberry-pie without sugar, or a dress-suit without a linen collar. Certain combinations are essential to the requirements of developed taste and present a problem of complementary goods. Combinations of complementary goods enhance the enjoyment; inharmonious combinations decrease it. That certain things "go together" is a fact that rests often in the nature of things. Complementary colors please the eye; well-seasoned dishes please the palate.