Certain questions regarding value, or price, that should be kept separate were sometimes confused by early economists. (1) What determines the price of a good? In the language of modern economics, what determines relative prices? (2) What determines the general level of prices? (3) What is the best measure of welfare? The first and third questions are part of modern microeconomics; the second, although it defies the usually simple micro-macro dichotomy, is generally included under the broad umbrella of macroeconomics. Smith did not provide an unambiguous answer to any of these different questions. His treatment of them is, in places, confusing in this regard because he intermingled his discussion of what determines relative prices with his attempt to discover a measure of changes in welfare over time.
It is not surprising that historians of economic ideas have argued over Smith's true opinion. One group of writers holds that Smith had three theories of relative prices (labor cost, labor command, and cost of production) and a theory explaining the general level of prices. Another group maintains that he settled on a cost of production theory of relative prices, a theory measuring changes in welfare over time, and a theory of the general level of prices. The latter group denies that Smith had a labor theory of relative prices. We believe that Smith experimented with all these theories: a theory of relative prices consisting of labor cost and labor command for a primitive society and cost of production for an advanced economy; the formulation of an index measuring changes in welfare over time; and a theory explaining the general level of prices. We first consider his theory of relative prices.
Although Adam Smith explained relative prices as determined by supply or costs of production alone, he did not completely ignore the role of demand. He believed that market, or short-run, prices are determined by both supply and demand. Natural, or long-run equilibrium, prices generally depend upon costs of production, although Smith sometimes stated that natural price depends upon both demand and supply. These inconsistencies provide ample opportunity for historians of economic theory to debate Smith's real meaning.
Smith's analysis of the formation of relative prices in the economy of his time distinguishes two time periods, the short run and the long run, and two broad sectors of the economy, agriculture and manufacturing. During the short-run, or market, period, Smith found downward-sloping demand curves and upward-sloping supply curves in both manufacturing and agriculture; therefore, market prices depend upon demand and supply. Smith's analysis of the more complicated "natural price," which occurs in the long run, contains some contradictions. For the agricultural sector, natural price depends upon supply and demand because the long-run supply curve is upward-sloping, indicating increasing costs. But for the manufacturing sector, the long-run supply curve is at times assumed to be perfectly elastic (horizontal), representing constant costs, and in other parts of the analysis is downward-sloping, indicating decreasing costs. In manufacturing, when the long-run supply curve is perfectly elastic, price depends entirely on cost of production; but when it is downward-sloping, natural price depends upon both demand and supply.
There are a number of possible interpretations of Smith's statements with regard to the forces determining natural prices for manufactured goods. One may assume that he was merely inconsistent—possibly because of the long period of time it took him to write Wealth of Nations—or that he thought these issues were of minor importance. Another approach is to select one of his statements on manufacturing costs as representative of "the real Adam Smith." It makes little difference which approach is employed, because Smith consistently noted the role of demand in the formation of natural prices and in the allocation of resources among the various sectors of the economy. Nevertheless, regardless of the shape of the long-run supply curve in manufacturing, the major emphasis in the determination of natural prices is on cost of production, an emphasis that is characteristic of Smith and subsequent classical economists.
The scholastics became interested in the question of relative prices because they were concerned with the ethical aspects of exchange, and the mercantilists considered it because they thought wealth was created in the process of exchange. Even though Smith on occasion discussed prices in ethical terms, he had a more important reason for being interested in the factors determining relative prices.
Once an economy practices specialization and division of labor, exchange becomes necessary. If exchange takes place in a market such as the one existing at the time Smith wrote, certain obvious problems arise.
The Meaning of Value
Smith believed that the word value has two different meanings, and sometimes expresses the utility of some particular object, and sometimes the power of purchasing other goods which the possession of that object conveys. The one may be called "value in use"; the other, "value in exchange." The things which have the greatest value in use have frequently little or no value in exchange; and on the contrary, those which have the greatest value in exchange have frequently little or no value in use. Nothing is more useful than water: but it will purchase scarce any thing; scarce any thing can be had in exchange for it. A diamond, on the contrary, has scarce any value in use; but a very great quantity of other goods may frequently be had in exchange for it.
According to Smith, value in exchange is the power of a commodity to purchase other goods—its price. This is an objective measure expressed in the market. His concept of value in use is ambiguous; it resulted in a good part of his difficulties in explaining relative prices. On the one hand, it has ethical connotations and is therefore a return to scholasticism. Smith's own puritanical standards are particularly noticeable in his statement that diamonds have hardly any value in use. On the other hand, value in use is the want-satisfying power of a commodity, the utility received by holding or consuming a good. Several kinds of utility are received when a commodity is consumed: its total utility, its average utility, and its marginal utility. Smith's focus was on total utility—the relationship between marginal utility and value was not understood by economists until one hundred years after Smith wrote—and this obscured his understanding of how demand plays its role in price determination. It is clear that the total utility of water is greater than that of diamonds; this is what Smith was referring to when he pointed to the high use value of water as compared to the use value of diamonds. However, because a commodity's marginal utility often decreases as more of it is consumed, it is quite possible that another unit of water would give less marginal utility than another unit of diamonds. The price we are willing to pay for a commodity—the value we place on acquiring another unit—depends not on its total utility but on its marginal utility. Because Smith did not recognize this (nor did other economists until the 1870s), he could neither find a satisfactory solution to the diamond-water paradox nor see the relationship between use value and exchange value.
Smith on Relative Prices
Because Smith was somewhat confused about the factors determining relative prices, he developed three separate theories relating to them. (1) a labor cost theory of value, (2) a labor command theory of value, and (3) a cost of production theory of value. He postulated two distinct states of the economy: the early and rude state, or primitive society, which is defined as an economy in which capital has not been accumulated and land is not appropriated; and an advanced economy, in which capital and land are no longer free goods (they have a price greater than zero).
Labor cost theory in a primitive society.
In the early and rude state of society which precedes both the accumulation of stock [i.e., capital] and the appropriation of land, the proportion between the quantities of labour necessary for acquiring different objects seems to be the only circumstance which can afford any rule for exchanging them for one another. If among a nation of hunters, for example, it usually costs twice the labour to kill a beaver which it does to kill a deer, one beaver should naturally exchange for or be worth two deer.
According to Smith's labor cost theory, the exchange value, or price, of a good in an economy in which land and capital are nonexistent, or in which these goods are free, is determined by the quantity of labor required to produce it. This brings us to the first difficulty with a labor cost theory of value. How are we to measure the quantity of labor required to produce a commodity? Suppose that two laborers are working without capital, that land is free, and that in one hour laborer Jones produces one unit of final product and laborer Brown produces two units. Assume that all other things are equal—or, to use the shorthand expression of theory, ceteris paribus—so that the only cause of the differences in productivity is the difference in the skills of the workers. Does a unit of output require one hour of labor or two? Smith recognized that the quantity of labor required to produce a good cannot simply be measured by clock hours, because in addition to time, the ingenuity or skill involved and the hardship or disagree-ableness of the task must be taken into account.
Labor theory in an advanced economy. Smith's model for an advanced society differs from his primitive economy model in two important respects—capital has been accumulated and land appropriated. They are no longer free goods, and the final price of a good also must include returns to the capitalist as profits and to the landlord as rent. Final prices yield an income made up of the factor payments of wages, profits, and rents.
Cost of production theory of relative prices. Smith wrestled with developing a labor theory of value for an economy that included more than labor costs in the final prices of goods, but finally abandoned the idea that any labor theory of value was applicable to an economy as advanced as that of his times. Once capital has been accumulated and land appropriated, and once profits and rents as well as labor must be paid, the only appropriate explanation of prices, he seems to have found, was a cost-of-production theory. In a cost theory the value of a commodity depends on the payments to all the factors of production: land and capital in addition to labor. In Smith's system, the term profits includes both profits as they are understood today and interest. The total cost of producing a beaver is then equal to wages, profits, and rent, TCb = Wb + Pb + Kb; likewise for a deer, TCd = Wd + Pp + R-d- The relative price for beaver and deer would then be given by the ratio of TCb/TCd- Where Smith assumed that average costs do not increase with increases in output, this calculation gives the same relative prices whether total costs or average costs are used. Where Smith assumed that average costs change with output, prices depend upon both demand and supply. However, in his analysis of the determination of long-run natural prices, Smith emphasized supply and cost of production, even when the supply curve was not assumed to be perfectly elastic. Where competition prevails, he maintained, the self-interest of the businessman, laborer, and landlord will result in natural prices that equal cost of production.