Front Page Titles (by Subject) CHAPTER 4: PRINCIPLES OF EVALUATION - Economics, vol. 1: Economic Principles
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CHAPTER 4: PRINCIPLES OF EVALUATION - Frank A. Fetter, Economics, vol. 1: Economic Principles 
Economics, vol. 1: Economic Principles, (New York: The Century Co., 1915).
Part of: Economics, 2 vols.
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PRINCIPLES OF EVALUATION
§ 1. Quality, a reflection of desire. § 2. Substitution of goods. § 3. The principle of substitution. § 4. Substitution of like and of unlike goods. § 5. Complementary goods. § 6. Changes of desires and of valuations. § 7. Effect of repeated stimuli on our feelings. § 8. Different quantities and corresponding desires. § 9. Stock of homogeneous units: principle of indifference. § 10. Diagram of marginal valuation. § 11. The paradox of value.
§ 1. Quality, a reflection of desire. Our task now is to explain—in the case of present, directly enjoyable goods—the elementary principles of valuation. We have already seen that things have inherent physical and chemical qualities which are quite beyond the power of man to change. We can go further than this and say that no two objects are exactly alike. Each object is in an extremely literal sense a “unique.” “Alike as two peas” means merely so near to likeness that the eye cannot detect the difference. The differences are minute, and for many practical purposes quite negligible. It is such a degree of likeness for practical purposes which we have in mind when we speak of a “grade” of goods, and (somewhat inconsistently) of “like” goods having different qualities. Thus all apples may be spoken of as being “like” goods. They are alike botanically; they are also alike to a degree in the uses of which they are put. There are, nevertheless, different varieties of apples, and the apples of a given variety may always be “graded”—according to size, or to color, or to degree of perfection—when the grower uses them himself or prepares them for the market. These differences are inherent in the apples themselves. When, however, we speak of apples of “good quality” or “bad quality,” we mean simply that we desire the so-called good ones more than the so-called bad ones. As between two apples, the one which we desire the more is spoken of as of “good” or “superior” quality. But plainly the goodness or the superiority lies in the relation to our desires. So that quality is partly a matter of inherent differences, and partly a reflection of our desires. Thus if (in Fig. 3) 1, 2, 3, and 4 are apples which are practically alike except in one particular—sweetness, for example—and if we have a preference for sweet apples we are likely to rank them as to value according to their sweetness.
§ 2. Substitution of goods. If now we have an abundance of apples of the greatest sweetness or best flavor, those of inferior quality will make little appeal to our desires. The best apples have a high value; the poorest have little or none. Because of their abundance, or the abundance of the better grades, the apples of inferior quality may even be free goods, lacking in value because not in the smallest degree the objects of desire. If, on the other hand, apples of the finest flavor are few in number, those of the next best grade will become objects of desire, and will therefore have a value for us. We come in this way to attach different values to the different grades. This act of resorting to objects of inferior quality because of the scarcity of the better grades, is substitution of goods. It is but the objective aspect of the shifting in our desires. It is a simple matter, but it has its bearing on the general problem of value. The thing that is fundamental in the valuation of different grades of things is the connection between these various grades and the desires of men.
In some years, when the difference in quality between the grades of apples is marked and there is a large crop of the best grade, the small, knotty apples are free goods in the orchards, and are allowed to rot on the ground. In other years, when good apples are scarce, the poorer grades are gathered and are sold at good prices. But if there is an abrupt difference in quality between two grades, the value of the better grade may rise considerably before there is any use made of the poorer. The slighter the difference in quality the more quickly appears the effect of the presence of the lower grades in limiting the increase of value of the higher grades.
§ 3. The principle of substitution. Substitution of goods in the simplest case occurs where an individual is distributing two or more goods or kinds of goods to different uses. His object is to gratify his desires to the maximum, by economizing the more valuable goods and making the less valuable goods serve some of the same purposes. This may be expressed as a general principle of substitution as follows: goods of kinds and of grades the most valuable are applied to the more urgent uses they are capable of meeting, and less valuable goods are brought in to take their place (substituted) up to the point where the value of each use and the value of the good applied to it are equal.
No grade can be said to be the cause of the value of the others. There is an independent reason for the attaching of value to each grade of goods. Each grade would have value if there were none of the other. But they mutually affect each other’s value when they exist side by side. The value of each is lessened by the presence of the other. And thus two or many grades constitute for many purposes a single group of goods which shade gradually into each other by the shifting of choice.
§ 4. Substitution of like and of unlike goods. The cases of substitution most easily called to mind are between goods very nearly alike in physical nature and used for the same general purpose; cotton and wool for clothing; fish and venison, or peaches and pears, for food; candles and petroleum for light; stone, brick, and wood for house building; horses, mules, and oxen for hauling. But cases may be found which range in almost unbroken series in either direction—towards the substitution of practically like goods on the one hand and towards the substitution of most unlike goods on the other. One may go without overshoes to get books, without candy to go to the theater, without adequate food to get an education.
§ 5. Complementary goods. Some goods, however, instead of being substitutes have a complementary relation to each other. Two or more kinds of economic goods are said to be complementary when either one, instead of taking the place of the other, enhances its desirability. The one complements (fills out, completes) the other. Cases occur where the one good is entirely useless without the other, as the two gloves of a pair, a gun without powder, fuel without flame to light it, etc. In another class of cases the one is still of some value, but of less value, without the other, as salt in the food, one of a finely matched pair of horses, etc. In one way or another and at various times, a great many most unlike goods may become linked together in choice by this complementary quality. This gives rise to interesting, sometimes puzzling, problems of valuation. A group of complementary goods is valued as a whole; but if one part is missing the rest may be worth nothing, and a part may for the moment be worth as much as the whole. If a good in one of its possible uses is highly complementary, perhaps indispensable to another good, it will be valued for that use, and a substitute found in other uses. Economics is full of problems of complementary goods. Some of these occur in the use of enjoyable goods, and still more occur in production by means of complementary agents, the consideration of which must be postponed till later in our study.
§ 6. Changes of desires and of valuations. Choice is constantly being affected by changes within men (subjective) as well as by changes in the objective conditions. Desire is constantly shifting; different kinds of goods are at every moment being revalued according to the new conditions. The use of one unit of a good causes the valuation of the remaining portions to drop down the scale for the next moment. When we rise in the morning, we desire 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 desires are gratified, are altered, and are shifted, until, wearied with the day’s labors and pastimes, we go to rest. No impression on the nerves or on the senses is lasting. The “consciousness” is not a state; it is a ceaseless process. Man’s senses were evolved for the purpose of bringing him into relation with the outer world, of enabling him to survive in his struggle with the forces of nature. When a choice occurs, the corresponding desire falls for that particular moment, it may be even to zero. To keep desires satisfied is impossible. Desires recur for the same reason that they first arose. If they did not there would be no motive for action. We can not do next week’s reading or next week’s eating now. The best results in reading or eating come from taking the right amount day by day. In a well-ordered life, in an advanced, economic society, the means for gratifying desires 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.
§ 7. Effect of repeated stimuli. It is in the very nature of man and his nervous organization that any stimulus to the nerves, however pleasant for a time, becomes painful when long continued or increased unduly. The trumpet too distant at first for the ear to distinguish its notes, may swell to pleasing tones as it approaches, until at length its volume and its din may become absolutely painful. A man coming in from the winter storm and holding out his hands before the fire enjoys the warmth intensely; a few minutes later the same heat becomes unpleasant. In winter we wish for a moderation of the temperature; on the sultry days of summer we think of a cool breeze as the most to be desired of all things. Whether the temperature rises or falls, there is a point beyond which the change no longer adds to our comfort but begins to detract from it. A man, however hungry at first, may be made miserable if forced to eat beyond his capacity. The first sup of cool water is delicious to a thirsty man; a second and third glass, but not more, may still be grateful. Forcing one to take an excessive amount of water is one of the cruelest of tortures (sometimes called the “water cure”). Of every economic object it may be said, “One may have too much of a good thing.” The statement of this relativity of desires and successive gratification, is called the principle of diminishing gratification.1
§ 8. Different quantities and corresponding desires. It has already been made clear that the scarcity or abundance of a good has its effect upon our desire for that good. We can make use of more or less of it, but not of an infinite amount. If a very small quantity is available, we may use that quantity and still feel a fairly intense desire for more. If the quantity available is large, our consumption may be increased, but a desire (less intense) for more may still remain. A limit will be found somewhere, however, to the use that we can make of the good, and if this limit is reached—if the quantity available is so great that absolutely all our desires for it are satisfied—the value of the good will fall to zero for the reason that desire has completely ceased. Clearly the intensity of desire changes—and changes inversely—with the quantity of the goods available. If now we may be allowed the latitude of speaking of these various intensities of desire as different desires, we may say that there is a series of desires capable of being gratified by various quantities of the good in question. A small amount will gratify the greatest or most intense desire, an additional amount of the good will meet the desire which comes next in intensity, and so on until finally we reach the point where, with the whole series of desires already met, an additional amount finds desire completely lacking and value therefore at the zero point.
§ 9. Stock of homogeneous units; principle of indifference. If now we consider a quantity (stock) of the good which is capable of gratifying a part, but not all, of our desires, it is plain that a value will attach to the good. If it is a stock made up of homogeneous or identical units, there is no reason for preferring any particular unit to any other.
True, in advance of using the goods, we say that some of the desires are more intense than the others. But when we begin to use a stock of homogeneous units this difference must disappear. For we will begin by applying the goods first to the more intense desires, and as we have just seen, this reduces their intensity. We then apply goods to the desire formerly ranking next in intensity. And so successively, we apply the goods to the more intense desires remaining, and as they fall in intensity we take in, one after another, the desires which at first were less intense, continuing until the whole stock of goods has been applied. In this way we bring to equality the values of all the units that are actually used (if the goods are divided into very small units). We have come to the limit, or the margin, of the series of desires that this stock of goods is capable of gratifying, and outside of this limit may remain various ungratified desires.
The marginal desire (originally the least intense of the desires now gratified) now marks and expresses the actual value of each of the other units of the stock. This is the marginal valuation. The stock being made up of homogeneous units, equally fitted to gratify any one of the series of desires, no unit can be valued at the moment more than any other unit. The aspect of valuation here presented is called either the marginal principle (thinking of the least intense desire), or the principle of indifference (thinking of the equal fitness of the objective units), and may be expressed as follows: each unit of a stock of homogeneous goods which is actually at hand and equally convenient for use, is of equal value with every other unit, no matter to what use it is there applied. Of course this holds only as to the particular time and set of conditions, and desires may change in the next moment.
§ 10. Diagram of marginal valuation. This principle of valuation may be illustrated by the following diagram in which horizontal distance represents stocks of goods of various amounts, and perpendicular distance represents marginal valuation or value per unit. Let us assume that in the case of a stock of ten units the marginal valuation (value per unit) is 36. The value then ascribed to the whole stock will be 360 (represented on the diagram by the rectangle ab). If instead of a stock of ten we consider a stock of fifteen, then since fifteen units will gratify more desires than ten units, leaving fewer desires still unsatisfied, the marginal valuation will be lower—for example 30 instead of 36. In this case the value of the stock is 450 (rectangle ac). And similarly, for stocks of various amounts, we get marginal and total valuations as shown in the following table:
The first thing of significance in the diagram is that the marginal valuation, or value per unit, is large in the case of a small stock, and small in the case of a large stock. And this means simply that when we have a small supply of a commodity we set a high value (per unit) upon it; when we have a large supply its value per unit to us is small. This, of course, is a familiar fact of daily experience.2
§ 11. The paradox of value. One thing more may be pointed out by way of further study of the diagram. Corresponding with any given stock—for example a stock of ten units—there is a rectangle (Fig. 5, ab) which represents graphically the total value of the stock—that is, the product of the value per unit by the number of units. In the case of a very small stock this rectangle will be very small. On the other hand, in the case of a very large stock, since the value per unit is small and may even reach zero, the rectangle will also be very small, reaching zero, as we have already seen, in the case of free goods. Somewhere in between these two extremes, of course, there will be a maximum rectangle (Fig. 5, af), a stock the total value of which is greater than that of either a larger or a smaller stock. This fact (brought out also in the third column of the table) that after a certain point an increase of the total stock will result in a decrease of the total value, has been called the “paradox of value.” Cases have been known of the partial destruction of a stock of goods by its owners as the result of their calculation that the remainder would actually sell on the market for more than could be secured for the whole original supply.
The Weber-Fechner Law. In part the effects of repeated stimuli are probably explained by a law of psychology. It is that geometric increase of the stimuli acting on any of the senses is required to produce an arithmetic increase of sensation. It holds “approximately and within a certain middle region of the intensive scale for intensities of noise and tone, of pressure, of various kinesthetic complexes (lifted weights, movements of the arms, movements of the eyes), and of smell.” “There is some little evidence that affection on the intensive side obeys Weber’s law.” (Titchener, “A Text book of Psychology,” 1911, pp. 218, 259.)
The points on the curve R1 to R4 indicate the total stimuli (measured on the ordinate by scale shown at right) required to produce a given degree of sensation, shown by abscissas measured on line S0 to S4. While the stimuli increase in geometric ratio (1, 2, 4, 8) the sensations increase in an arithmetic ratio (1, 2, 3, 4.) The relative quantity of sensation perunit of stimulus is represented by the height of a, b, c, d respectively above the base line. The second R produces sensation equal to the first, the third and fourth R (average) produce ½ as much sensation, the 5th to 8th R (average) produce ¼ as much. The curve a-d corresponds with the observed trend of decreasing valuation in many cases. It is clear, however, that valuation does not always (perhaps not usually) rise and fall in curves exactly parallel with sensation; for example, a first and a second unit of R might (if there were no more) be neither pleasurable nor valuable; a third and fourth might raise the total sensation to a degree where it was desirable and valuable; and not until the fifth or some latter unit would an additional unit of R add a smaller proportional value. The correspondence between decreasing sensation and decreasing valuation is thus found only at certain middle regions of the scale.
[1 ]See note on the Weber-Fechner law, at end of chapter.
[* ]To show this graphically, let the units of goods be plotted on the base line. If but one were present its desirability measured on the perpendicular (valuation scale) or parallel with it, is indicated at the height d; if there were a second unit its desirability would be indicated by e; and so on until with six units the value of the sixth would be c. But if the units are perfectly interchangeable, the value of every unit would now be the same as that of the last, and is measured by the height of the straight line bc above the base line, and not by the height of the curve ac.
[2 ]It is evident that the various parts of a stock of goods can be valued on the marginal principle only when it is possible to choose among the various units and to apply them to various uses in such proportions as one will. If another person controls the whole stock and compels us to choose “all or none” we may be forced to value the whole stock according to our more intense desires. This is a fact of great importance in some practical problems, such as those of monopoly.