Why do individuals assign a greater value to gold than to bread, when bread seems to be more “useful” than gold? To provide an answer to this question economists refer to the law of diminishing marginal utility. The concept of diminishing marginal utility is the essential building block of economics. There is, however, a difference in the way this law is discussed by mainstream economics and the Austrian school of economics.
The Mainstream Approach
The popular economics explains this law in terms of the satisfaction that one derives from consuming a particular good. For instance, an individual may derive vast satisfaction from consuming one cone of ice cream. The satisfaction he will derive from consuming a second cone might also be large but not as large as the satisfaction derived from the first cone. The satisfaction from the consumption of a third cone is likely to diminish further, and so on.1
From this economists have concluded that the more of any good we consume in a given period, the less satisfaction, or utility, we derive from each additional unit. From this it is established that if the satisfaction from the additional unit of a good declines as we consume more and more of it, the price that we are willing to pay per unit of the good is also going to decline.
Now, according to this framework of thinking, since gold is relatively less abundant than bread it follows that the price of gold should be ranked higher than the price of bread because the benefit derived from the additional unit of bread is going to be much lower than the benefit derived from the additional unit of gold. On the same basis, it can also be deduced that although air is essential to human life, because of its almost unlimited supply individuals are likely to assign it a much lower price than bread.
Utility in this way of thinking is presented as a certain quantity that increases at a diminishing pace as one consumes or uses more of a particular good. Given that utility is presented as some total quantity, also called the total utility, it becomes possible to introduce mathematics here to ascertain the addition to this total, which is called the additional utility or marginal utility. In this way of thinking, human action is not navigated by reason but by biological needs.
Menger’s Explanation
According to Carl Menger, the founder of the Austrian school, individuals assign priorities to various goals that they want to achieve. The standard for setting priorities is the individual’s life. Those ends that are of utmost importance for the individual’s life maintenance are going to be assigned the highest ranking, while ends that are of lesser importance to life maintenance are going to be assigned a lower ranking.
As concerns the differences in the importance that different satisfactions have for us, it is above all a fact of the most common experience that the satisfactions of greatest importance to men are usually those on which the maintenance of life depends, and that other satisfactions are graduated in magnitude of importance according to the degree (duration and intensity) of pleasure dependent upon them. Thus if economizing men must choose between the satisfaction of a need on which the maintenance of their lives depends and another on which merely a greater or less degree of well-being is dependent, they will usually prefer the former.
Consider John the baker, who has produced four loaves of bread. The four loaves are the means that John employs to attain various goals or ends. Let us say that his highest priority, or his highest end as far as life maintenance is concerned, is to have a loaf of bread for his personal consumption. The loaf of bread is of utmost importance to John in order to support his life.
The second loaf of bread enables John to secure five tomatoes for his personal consumption. By means of five tomatoes, John attains his second most important end as far as his life maintenance is concerned. In order to secure the five tomatoes John must exchange a loaf of bread for them. Let us say that John was successful and finds a tomato farmer that agrees to exchange his five tomatoes for the loaf of bread.
John uses the third loaf of bread to exchange it for the third most important end, which is to have a shirt. Finally, John decides that he will allocate his fourth loaf of bread to feed wild birds.
Note that feeding wild birds is John’s fourth end—the least important end. The fourth loaf of bread is the last unit in John’s total supply of bread. It is also called the marginal unit, or the unit at the margin.
The marginal unit secures the least important end. Alternatively, we can also say that as far as life is concerned, the marginal unit provides the least benefit.
Observe that to attain the second and the third ends John had to exchange his resources—loaves of bread—for goods that would serve to achieve his ends.
To secure the end of having a shirt, John had to exchange his loaf of bread for the shirt. The loaf of bread is not suitable by itself to fulfill the services that the shirt provides. Similarly, to secure the end of having five tomatoes, John had to exchange a loaf of bread for five tomatoes.
Note that the first loaf of bread is employed to secure the most important end, the second loaf of bread the second most important end, etc.
Ends Determine the Value of Means
A given end determines the specific means that an individual is likely to select for the attainment of that end. For instance, to secure the end of having a shirt John would have to select among various shirts the most suitable for his specific end—to have a work shirt, let us say.
Being a baker, John may conclude that the shirt must be of a white color and made out of a thin rather than thick material to keep him comfortable while working next to a hot oven.
Furthermore, we can also infer that the end assigns an importance to the resource employed. This implies that the first loaf of bread carries much higher importance than the second loaf of bread because of the more important end that the first loaf of bread secures.
Since the individual’ s ends determine his valuation of means and thus his choices, it follows that the same good is going to be valued differently by an individual as a result of changes in his ends.
While as a rule individuals assign a greater value to gold versus water, this need not be always the case. To quell his thirst in the desert, the individual requires water. Any gold in his possession is going to be of no help in this regard. The individual is going to assign the highest ranking to having water to maintain his life in the desert. Gold is going to have very low importance here.
Why Does the Least Important End Determine the Value of Each Unit?
Now, John regards each of the four loaves of bread in his possession as interchangeable. How, then, is he going to value each of the four loaves? He is going to value each one in accordance with the least important end, which is feeding wild birds. Why does the least important end serve as the standard for valuing the loaves of bread?
Consider that John is using the first end as the standard for assigning value to each loaf of bread. This would imply that he values the second, third, and fourth loaves much more than he values the second, third, and fourth ends.
However, if this is the case, what, then, is the point of exchanging something that is valued more for something that is valued less? Observe that to satisfy his second end, which is to have five tomatoes; John would have to exchange one loaf of bread for five tomatoes. (Note that five tomatoes, which is the second end, is assigned a lower value than the first end). If John assigns a higher value to a loaf of bread than to five tomatoes, most likely no exchange will take place.
Observe, that the fourth loaf of bread is the last unit in John’s total supply; it is also called the marginal unit (i.e., the unit at the margin). This marginal unit secures the least important end as far as life maintenance is concerned.
If John had only three loaves of bread, each loaf would be valued according to the third end—having a shirt. This end is ranked higher than the end of feeding wild birds.
From this, we can infer that as the supply of bread declines, every loaf of bread is going to be valued much more than before the decline. Conversely, as the supply of bread rises, each loaf will be valued less than before the supply increased.
Also, observe that ends are not set arbitrarily but graded in accordance with their importance in maintaining life. If John had ranked his ends randomly and without any thought then he would have run the risk of endangering his life.
For instance, if he had allocated most of his resources to clothing and to feeding wild birds and very little to feeding himself, he would then have run the risk of weakening his body.
Utility Is Not Some Measurable Quantity
In Menger’s framework, utility is not about quantities but about priorities, or the ranking of various ends with respect to an individual’s life.2 One cannot, however, add up priorities as such.
Consequently, marginal utility is not, as the mainstream perspective maintains, an addition to the total utility but rather the utility of the marginal end.
Since total utility cannot be quantified, various economic models that employ mathematical methods based on the view that such a total exists are questionable.
According to Rothbard,
Many errors in discussions of utility stem from an assumption that it is some sort of quantity, measurable at least in principle. When we refer to a consumer’s “maximization” of utility, for example, we are not referring to a definite stock or quantity of something to be maximized. We refer to the highest-ranking position on the individual’s value scale. Similarly, it is the assumption of the infinitely small, added to the belief in utility as a quantity, that leads to the error of treating marginal utility as the mathematical derivative of the integral “total utility” of several units of a good. Actually, there is no such relation, and there is no such thing as “total utility,” only the marginal utility of a larger-sized unit. The size of the unit depends on its relevance to the particular action.3
Note that both the mainstream approach and Menger’s way of thinking emphasize the importance of the relative quantity of a good in determining its price.
The difference, however, is that the mainstream relies on psychology while Menger emphasizes the importance of the purpose that a good helps to achieve.
The mainstream approach highlights the satisfaction an individual derives from an additional unit of a thing (i.e. biological needs).
Menger’s framework emphasizes the facts of reality that must be figured out and considered for life maintenance.
Thus, in order to maintain his life, John requires a loaf of bread—this is of utmost importance to keep him healthy. To have a loaf of bread is the fact of reality that John must consider if he wants to stay healthy.
To have a working shirt is also important to John. He has to decide what kind of shirt he should have that is going to make him comfortable. John would have to figure all this out. His decision is going to be based on a thought process.
Note, again, in the mainstream approach, utility is regarded as some kind of quantity which can be subjected to the rules of mathematics. This is, however, not so in Menger’s framework, where utility refers to the ranking of goods with respect to life, which is assigned as the most important end.
In addition, in the mainstream approach there is a strong emphasis on indifference curves, which supposedly could be helpful in understanding individuals’ choices. Indifference, however, has nothing to do with individuals’ purposeful conduct. When confronted with various goods, an individual makes his choice based on the suitability of goods to be employed as means to various ends, which are ranked with respect to an individual’s life.
In conclusion, it does not make sense to discuss the marginal utility of a good without referring to the purpose that this good serves. The marginal utility theory as presented by popular economics describes an individual without any goals and who is driven by psychological factors. This individual is not aiming consciously to reach his goals.
1. See Karl E. Case and Ray C. Fair, Principles of Microeconomics, 7th ed. (Amsterdam: Prentice Hall, 2003).
2. Murray N. Rothbard, Man, Economy, and State, with Power and Market, 2d scholar’s ed. (Auburn, AL: Ludwig von Mises Institute, 2009), pp. 302–10.
3. Rothbard, Man, Economy, and State, with Power and Market, pp. 305–06.
