In the process of exchange, the products of different concrete forms of labor are equalized and thus labor is also equalized. If other conditions remain unchanged, differences in concrete forms of labor play no role in the commodity economy and the product of one hour of labor of the shoemaker is equalized with the product of one hour of labor of the tailor. However, the different forms of labor take place in unequal conditions; they differ from each other according to their intensiveness, their danger to health, the length of training, and so on. The process of exchange eliminates the differences in the forms of labor; at the same time it eliminates the different conditions and converts qualitative differences into quantitative ones. Due to these different conditions, the product of one day's labor of the shoemaker is exchanged, for example, for the product of two days' labor of an unqualified construction worker or excavator, or for the product of half a day's labor of a jeweller. On the market, products produced in unequal amounts of time are equalized as values. At first glance this conception contradicts the basic premise of Marx's theory, according to which the value of the product of labor is proportional to the labor-time expended on its production. Let us see how this contradiction can be resolved.
Among the different conditions of labor mentioned above, the most important are the intensiveness of the given form of labor and the length of training and preparation required for the given form of labor or the given profession. The question of the intensiveness of labor is not a special theoretical problem and we will treat it incidentally. However, our main attention will be devoted to the question of qualified labor.
First of all we will define qualified and simple labor. Simple labor is "the expenditure of simple labor-power, i.e., of the labor-power which, on an average, apart from any special development, exists in the organism of every ordinary individual" (C., I, p. 44; Rubin's italics). As opposed to simple labor, we will call qualified labor that labor which requires special training, i.e., "longer or professional training and more significant general education than the average for workers."  One should not think that simple, average labor isa magnitude which is equal among different people and which does not change in the course of historical development. Simple average labor has a different character in different countries and in different cultural epochs, but it represents a given magnitude for each determined society at a given moment of its development (C., I, p. 44). The labor which any average worker can perform in England would require some kind of preparation for the worker in Russia. The labor which the average Russian worker is able to carry out at present, would have been considered labor which was above average, in terms of complexity, in Russia a hundred years ago.
The difference of qualified from simple labor is manifested: 1) in the increased value of the products which are produced by the qualified labor, and 2) in the increased value of the qualified labor force, i.e., in the increased wage of the qualified wage laborer. On one hand, the product of one day of labor of the jeweller has a value which is two times larger than the product of a day's labor of the shoemaker. On the other hand, the jewel-worker gets from the jewel entrepreneur a larger wage than the shoemaker gets from his entrepreneur. The first phenomenon is a property of the commodity economy as such, and characterizes the relations among people as producers of commodities. The second phenomenon is a property of the capitalist economy only, and characterizes relations among people as relations between capitalists and wage laborers. Since in the theory of value, which studies the properties of the commodity economy as such, we only deal with the value of commodities and not with the value of the labor force, in the present chapter we will consider only the value of products produced by qualified labor, leaving aside the question of the value of the qualified labor force.
The concept of qualified labor must be precisely distinguished from two other concepts which are frequently confused with it: ability (or dexterity) and intensiveness. Speaking of qualified labor we have in mind the level of average qualification (training) which is required for employment in the given form of labor, the given profession or specialty. This average qualification must be distinguished from the individual qualification of the single producer in the context of the same profession or specialty. The labor of the jeweller requires, on the average, a high level of qualification, but different jewellers display, in their work, different degrees of experience, training and skill; they differ from each other in terms of the dexterity or ability of their labor (C., I, pp. 38-39; 197). If shoemakers produce, on the average, one pair of shoes per day, and a given shoemaker who is abler and better trained produces two pairs, then naturally the product of one day's labor of the more qualified shoemaker (twopairs of shoes) will have two times more value than the product of one day's labor of the shoemaker of average ability (one pair of shoes). This is obvious since the value is determined, as will be shown in detail in the next chapter, not by the individual but by the labor socially necessary for the production. Differences in ability or dexterity among the two different shoemakers can be precisely measured in terms of the different quantities of products which they produced during the same time (given the same instruments of labor and other equal conditions). Thus the concept of ability or dexterity of labor enters into the theory of socially-necessary labor and does not present special theoretical difficulties. The question of qualified labor presents far larger problems. This is related to different values of products produced at the same time by two producers in different professions, producers whose products are not comparable with each other. Analysts who reduce qualified labor to ability simply circumvent the problem. Thus L. Boudin holds that the higher value of the product of qualified labor can be explained by the fact that the qualified laborer produces a larger quantity of products.  F. Oppenheimer says that Marx, who concentrated on "acquired" qualification, which results from "longer education and training," neglected "innate" qualification. But in our judgment, Oppenheimer included in this "innate" qualification the individual ability of particular producers, which is related to socially necessary, and not to qualified labor, where Oppenheimer placed it. 
Other analysts have tried to reduce qualified labor to more intensive labor. The intensity or tension of labor is determined by the quantity of labor which is expended in a unit of time. Just as we can observe individual differences in the intensity of labor between two producers in the same profession, so we can observe the different average intensity of labor in two different professions (C., I, p. 409, 524, 561). Goods produced by labor of the same duration but of different intensity have different value since the quantity of abstract labor depends not only on the length of the labor-time expended, but also on the intensity of the labor. (See the end of the previous chapter.)
Some analysts, as was mentioned above, have tried to resolve the problem of qualified labor by seeing in qualified labor, labor of higher intensity or tension. "Complex labor can produce greater value than simple labor only in conditions in which it is more intense than simple labor," says Liebknecht.  This greater intensity of qualified labor is expressed, first of all, in a greater expenditure of mental energy, in greater "attention, intellectual effort, and mental expenditure." Let us assume that the shoemaker spends 1/4 of a unit of mental energy per unit of muscular labor, and the jeweller expends 1 1/2 units. In this example, one hour of labor of the shoemaker represents the expenditure of 1 1/4 units of energy (muscular as well as mental), and one hour of labor of the jeweller represents 2 1/2 units of energy, i.e., the labor of the jeweller creates two times more value. Liebknecht himself is aware that such an assumption has a "hypothetical" character.  We think this assumption is not only unfounded, but is belied by the facts. We are taking into account forms of qualified labor which create commodities of higher value due to the length of training. But in terms of intensity, they do not exceed the intensity of less qualified forms of labor. We must explain why qualified labor, independent of the level of its intensity, creates a product of higher value. 
We face the following problem: why does the expenditure of equal labor-time in two professions with different average levels of qualification (length of training) create commodities of different value? In Marxist literature it is possible to note two different approaches to the solution of this question. One approach can be found in the work of A. Bogdanov. He notes that a qualified labor force "can function normally only on condition that more significant and varied needs of the worker himself are satisfied, i.e., on condition that he consume a larger quantity of different products. Thus complex labor-power has greater labor value, and costs the society a greater amount of its labor. This is why this labor power gives society a more complex, i.e.,'multiplied,' living labor."  If the qualified laborer absorbs consumer goods and, consequently, social energy which is five times greater than the simple laborer, then one hour of labor of the qualified laborer will produce a value which is five times greater than one hour of simple labor.
We consider Bogdanov's argument unacceptable, first of all in terms of its methodology. In essence, Bogdanov deduces the higher value of the product of qualified labor from the higher value of the qualified labor-power. He explains the value of commodities in terms of the value of the labor power. However, Marx's analytical path was just the opposite. In the theory of value, when he explains the value of commodities produced by qualified labor, Marx analyzes the relations among people as commodity producers, or the simple commodity economy; at this stage of the examination, the value of labor-power in general, and of qualified labor in particular, do not yet exist for Marx (C., I, p. 44, footnote).  In Marx's work, the value of commodities is determined by abstract labor which in itself represents a social quantity and does not have value. However, in Bogdanov's work, labor, or labor-time, which determines value, in turn also has value. The value of commodities is determined by the labor-time materialized in them, and the value of this labor-time is determined by the value of the consumer goods necessary for the subsistence of the laborer.  Thus we get a vicious circle which A. Bogdanov tries to get out of, by means of an argument which, in our opinion, is not convincing. 
Independently of these methodological defects, we must note that Bogdanov indicates only the minimal absolute limit below which the value of the products of qualified labor cannot go. The value must, under all circumstances, be sufficient to preserve the qualified labor force on its previous level, so that it will not be forced to de-qualify (sink to a lower level of qualification). But as we have pointed out, except for the minimal absolute limit, the relative advantage of different forms of labor plays a decisive role in the commodity economy.  Let us assume that the value of the product of a given type of qualified labor is completely adequate to maintain the qualified labor-power of the producer, but is not sufficient to make labor in the given profession relatively more advantageous than labor in other professions which require a shorter training period. In these conditions, a transfer of labor out of the given profession will start; this will continue until the value of the product of the given profession is raised to a level which establishes a relative equality in conditions of production and a state of equilibrium among the different forms of labor. In the analysis of the problems of qualified labor, we must take as our starting point, not the equilibrium between the consumption and the productivity of the given form of labor, but the equilibrium among different forms of labor. Thus we approach the basic starting-point of Marx's theory of value, we approach the distribution of social labor among different branches of the social economy.
In earlier chapters we developed the idea that the exchange of products of different forms of labor in terms of their values corresponds to the state of equilibrium between two given branches of production. This general position is completely applicable to cases where products of two forms of labor are exchanged, forms of labor which have different levels of qualification. The value of the product of qualified labor must exceed the value of the product of simple labor (or of less qualified labor in general) by the amount of value which compensates for the different conditions of production and establishes equilibrium among these forms of labor. The product of one hour of labor of the jeweller is equalized on the market with the product of two hours of labor of the shoemaker because equilibrium in the distribution of labor between these two branches of production is established precisely in the given exchange proportion, and the transfer of labor from one branch to the other ceases. The problem of qualified labor is reduced to the analysis of the conditions of equilibrium among different forms of labor which differ in terms ofqualification. This problem is not yet solved, but it is accurately posed. We have not yet answered our question, but we have already outlined the method, the path which will lead us to our goal.
A large number of Marxist analysts have taken this path.  They concentrated their main attention on the fact that the product of qualified labor is not only the result of the labor which is directly expended on its production, but also of that labor which is necessary for the training of the laborer in the given profession. The latter labor also enters into the value of the product and makes it correspondingly more expensive. "In what it has to give for the product of skilled labor, society consequently pays an equivalent for the value which the skilled labors would have created had they been directly consumed by society,"  and not spent on training a qualified labor force. These labor processes are composed of the master craftsman's and the teacher's labor, which is expended for training a laborer of a given profession, and of the labor of the student himself during the training period. Examining the question whether or not the labor of the teacher enters into the value of the product of qualified labor, O. Bauer is perfectly right in taking as the starting-point of his reasoning conditions of equilibrium among different branches of production. He reaches the following conclusions: "Together with the value created by labor, expended in the direct process of production, and with the value transferred from the teacher to the qualified labor force, value which is created by the teacher in the process of training is also one of the determining factors in the value of the products which are produced by qualified labor at the stage of simple commodity production." 
Thus, the labor expended in training the producers of a given profession enters into the value of the product of qualified labor. But in professions which differ in terms of higher qualifications and greater complexity of labor, the training of laborers is usually carried out by means of selection, from a larger number of the most capable students. From among three individuals studying engineering, perhaps only one graduates and achieves the goal. Thus, the expenditure of the labor of three students, and the corresponding increased expenditure of labor by the instructor, are required for the preparation of one engineer. Thus the transfer of students to a given profession,among whom only one third has a chance of reaching the goal, takes place to a sufficient extent only if the increased value of the products of the given profession can compensate the unavoidable (and to some extent wasted) expenditures of labor. Other conditions remaining equal, the average value of the product of one hour of labor in professions where training requires expenditures of labor by numerous competitors will be greater than the average value of one hour of labor in professions in which these difficulties do not exist.  This circumstance raises the value of the product of highly qualified labor. 
As we can see, the reduction of qualified to simple labor is one of the results of the objective social process of equalization of different forms of labor which, in capitalist society, is carried out through the equalization of commodities on the market. We do not have to repeat the mistake of Adam Smith, who "fails to see the objective equalization of different kinds of labor which the social process forcibly carries out, mistaking it for the subjective equality of the labors of individuals" (Critique, p. 68). The product of one hour of the jeweller's labor is not exchanged for the product of two hours of the shoemaker's labor because the jeweller subjectively considers his labor to be two times more valuable than that of the shoemaker. On the contrary, the subjective, conscious evaluations of the producers are determined by the objective process of equalization of different commodities, and through the commodities, by the equalization of different forms of labor on the market. Finally, the jeweller is motivated by calculating in advance that the product of his labor will have two times more value than the product of the shoemaker's labor. In his consciousness he anticipates what will happen on the market only because his consciousness fixes and generalizes previous experience. What happens here is analogous to what Marx described when he explained the higher rate of profit which is acquired in those branches of the capitalist economy which are connected with special risk, difficulty, and so on. "After average prices, and their corresponding market-prices, become stable for a time it reaches the consciousness of the individual capitalists that this equalization balances definite differences, so that they include these in their mutual calculations" (C., III, p. 209, Marx's italics). In just the same way, in the act of exchange the jeweller takes his high skill into account in advance. This high skill "is taken into account once and for all as valid ground for compensation" (C., III, p. 210). But this computation is only a result of the social process of exchange, a result of colliding actions of a large number of commodity producers. If we take the labor of an unqualified laborer (digging) as simple labor, and if we take one hour of this labor as a unit, then one hour of the jeweller's labor is equal, let us say, to 4 units, not because the jeweller evaluates his labor and assigns it the value of 4 units, but because his labor is equalized on the market with 4 units of simple labor. The reduction of complex to simple labor is a real process which takes place through the process of exchange and in the last analysis is reduced to the equalization of different forms of labor in the process of distribution of social labor, not to the different evaluations of different forms of labor or to the definition of differentvalues of labor.  Since the equalization of different forms of labor takes place, in the commodity economy, through the equalization of the products of labor as values, the reduction of qualified to simple labor cannot take place any other way than through the equalization of the products of labor. "A commodity may be the product of the most skilled labor, but its value, by equating it to the product of simple unskilled labor, represents a definite quantity of the latter labor alone" (C., I, p. 44). "The value of the most varied commodities is everywhere expressed in money, i.e., in a determined quantity of gold or silver. And precisely because of this, the different forms of labor represented by these values are reduced, in different proportions, to determined quantities of one and the same form of simple labor, namely that labor which produces gold and silver."  The assumption that the reduction of qualified to simple labor must take place in advance and precede exchange in order to make possible the act of equalization of the products of labor misses the very basis of Marx's theory of value.
As we can see, in order to explain the high value of the products of qualified labor we do not have to repudiate the labor theory of value; we must only understand clearly the basic idea of this theory as a theory which analyzes the law of equilibrium and distribution of social labor in the commodity-capitalist economy. From this point of view we can evaluate the arguments of those critics of Marx  who make the problem of qualified labor the main target of their attacks and see this as the most vulnerable part of Marx's theory. The objections of these critics can be reduced to two basic propositions: 1) no matter how Marxists might explain the causes of the high value of products of qualified labor, it remains a fact of exchange that the products of unequal quantities of labor are exchanged as equivalents, which contradicts the labor theory of value; 2) Marxists cannot show the criterion or standard by which we could equalize in advance a unit of qualified labor, for example one hour of a jeweller's labor, with a determined number of units of simple labor.
The first objection is based on the erroneous impression that the labor theory of value makes the equality of commodities dependent exclusively on the physiological equality of the labor expenditures necessary for their production. With this interpretation of the labor theory of value, one cannot deny the fact that one hour of the jeweller's labor and four hours of the shoemaker's labor represent, from a physiological point of view, unequal quantities of labor. Every attempt to represent one hour of qualified labor as physiologically condensed labor and equal, in terms of energy, to several hours of simple labor, seems hopeless and methodologically incorrect. Qualified labor is, in fact, condensed, multiplied, potential labor; it is not physiologically, but socially condensed. The labor theory of value does not affirm the physiological equality but the social equalization of labor which, in turn, of course takes place on the basis of properties which characterize labor from the material-technical and physiological aspects (see the end of the previous chapter). On the market, products are not exchanged in terms of equal, but of equalized quantities of labor. It is our task to analyze the laws of the social equalization of various forms of labor in the process of social distribution of labor. If these laws explain the causes of the equalization of one hour of the jeweller's labor with four hours of the unqualified worker's labor, then our problem is solved, irrespective of the physiological equality or inequality of these socially equalized quantities of labor.
The second objection of Marx's critics assigns to economic theory a task which is in no way proper to it: to find a standard of value which would make it operationally possible to compare different kinds of labor with each other. However, the theory of value is not concerned with the analysis or search for an operational standard of equalization; it seeks a causal explanation of the objective process of equalization of different forms of labor which actually takes place in a commodity capitalist society.  In the capitalist society, this process takes place spontaneously; it is not organized. The equalization of different forms of labor does not take place directly, but is established through the equalization of the products of labor on the market, it is a result of the colliding actions of a large number of commodity producers. In these conditions, "society is the only accountant competent to calculate the height of prices, and the method which society employs to this end is the method of competition."  Those critics of Marx who assign to simple labor the role of a practical standard and a unit for the equalization of labor in essence put an organized economy in the place of capitalist society. In an organized economy, different forms of labor are equalized with each other directly, without market exchange or competition, without the equalization of things as values on the market.
Rejecting this confusion of theoretical and practical points of view, and consistently holding to a theoretical point of view, we find that the theory of value explains, in a thoroughly adequate manner, the cause of the high value of highly qualified labor as well as the changes of these values. If the period of training is shortened, or in general if the labor expenditures necessary for training in a given profession are shortened, the value of the products of this profession falls. This explains a whole series of events in economic life. Thus, for example, starting with the second half of the 19th century, the value of the product of labor of store clerks as well as the value of their labor power fell significantly. This can be explained by the fact that "the necessary training, knowledge of commercial practices, languages, etc., is more and more rapidly, easily, universally and cheaply reproduced with the progress of science and public education" (C., Ill, p. 300).
In this, as in the previous chapter, we took as our starting-point a state of equilibrium among the various branches of social production and the different forms of labor. But as we know, the commodity capitalist economy is a system in which equilibrium is constantly destroyed. Equilibrium appears only in the form of a tendency which is destroyed and delayed by countervailing factors. In the field of qualified labor, the tendency to establish equilibrium among different forms of labor is weaker to the extent that a long period of qualification, or high costs of training in a given profession, put large obstacles on the transfer of labor from the given profession to other, simpler professions. When we apply a theoretical schema to living reality, the delayed effect of these obstacles must be taken into consideration. The difficulties of being admitted to higher professions gives these professions some form of monopoly. On the other hand, "a few [professions] of inferior kind, that are over-supplied with underpaid workmen" (C.,.I p. 440), are accessible. Frequently, the difficulty of being admitted to professions with higher skills, and the selection which takes place in this admission, throws many unsuccessful competitors into lower professions, thus increasing the over-supply in these professions.  In addition, the increasing technical and organizational complexity of the capitalist process of production intensifies the demand for new forms of qualified labor power, disproportionally increasing the payment for this labor force and for its products. This is, so to speak, a premium for the time expended to acquire qualifications (which may be shorter or longer). This premium arises in a dynamic process of change in the qualifications of labor. But just as the deviation of market prices from values does not disprove but makes possible the realization of the law of value, so the "premium for qualification," which signifies the absence of equilibrium among different forms of labor, in turn leads to the increase of qualified labor and to the distribution of productive forces in the direction of equilibrium of the social economy.
Otto Bauer, "Qualifizierte Arbeit und Kapitalismus," Die Neue Zeit, Stuttgart, 1906, Bd. I, No. 20.
Louis B. Boudin, The Theoretical System of Karl Marx in the Light of Recent Criticism, Chicago: Charles H. Kerr & Co., 1907.
 Franz Oppenheimer, Wert und Kapitalprofit, Jena: Ct. Fischer, 2nd edition, 1922, p. 63, pp. 65-66. A detailed critique of Oppenheimer's views is given in our Sovremennye ekonomisty na Zapade (Contemporary Economists in the West), 1927.
 Wilhelm Liebkneckt, Zur Geschichte der Werttheorie in England, Jena: G. Fischer, 1902, p. 102. The author of this book is the son of Wilhelm Liebknecht and the brother of Karl Liebkneckt. A detailed critique of Liebknecht's views was given in our introduction to the Russian translation of Liebknecht's History of the Theory of Value in England.
 Ibid., p. 103.
In P. Rumyantsev's Russian translation of A Contribution to the Critique of Political Economy, complex labor is called "labor of higher tension" (1922, p. 38). This term should not confuse the reader, since it is not Marx's term. In the original edition, Marx called it "labor of higher potential" (p. 6).
 A. Bogdanov, and I. Stepanov, Krus politicheskoi ekonomii (Course in Political Economy), Vol. II, No. 4, p. 19. Bogdanov's italics.
 In one passage Marx deviates from his usual method and tends to treat the value of the product of qualified labor as dependent on the value of the qualified labor power. See Theorien uber den Mehrwert, III, pp. 197-198.
 See F. Engels, Anti-Duhring, New York: International Publishers, 1966, PĚ 210.
 Op. cit., p. 20.
 See our similar objections to A. Bogdanov in the chapter on "Equality of Commodities and Equality of Labor."
R. Hilferding, Bohm-Bawerk's Criticism of Marx (New York: Augustus M. Kelley, 1949). H. Deutsch, Qualifizierle Arbeit und Kapitalismus, Wien: C.W. Stern, 1904. Otto Bauer, Op. Cit. V.N. Poznyakov, Kvalifitsirovannyi trud i teoriya tsennosti Marksa (Qualified Labor and Marx's Theory of Value), 2nd edition.
Hilferding, Op. Cit., p. 145.
 Bauer, Op. Cit., pp. 131-132.
 This view, which is already found in Adam Smith,was particularly emphasized by L. Lyubimov (Kurs politicheskoi ekonomii - Course of Political Economy - 1923, pp. 72-78). Unfortunately, L. Lyubimov mixed together the question of what determines the average value of products of a highly qualified profession, for example, engineers, artists, etc., with the question of what determines the individual price of a given unreproducible object (a painting by Raphael). When he treats reproducible mass-produced goods (for example the labor of an engineer can be treated as labor which produces - with small exceptions - homogeneous and reproducible products), we can obtain the value of a unit of product by dividing the value of the entire production of a given profession by the number of homogeneous products produced by that profession. But this is not possible with respect to individual, unreproducible objects. The fact that the wasted expenditure of labor of thousands of painters who failed is compensated in the price of a painting by Raphael, or that the wasted expenditure of labor of hundreds of unsuccessful painters is compensated in the price of a painting by Salvador Rosa, cannot in any way be derived from the fact that the average value of the product of one hour of labor of a painter is equal to the value of the product of five hours of simple labor (to each hour of the painter's labor is added one hour of labor spent by the painter for his training and three hours of labor expended on the training of three painters who failed). L. Lyubimov is completely right when he subsumes the value of the product of a highly qualified laborer under the law of value. But he cannot deny the fact of monopoly in relation to the individual price of unreproducible objects. P. Maslov commits the opposite error. He ascribes a monopolistic character to the average value of products of highly qualified labor as well (See his Kapitalizm - Capitalism - 1914, pp. 191-192).
Marx's goal was not to subsume the price of unreproducible objects under the law of value. He did not do this because of the simple reason that the law of value has to explain precisely the laws of human productive activities. In his theory of value, Marx does not treat the value of products which "cannot be reproduced by labor, such as antiques and works of art by certain masters, etc." (C., III, p. 633).
 In capitalist society, the interest on training expenditures is sometimes added; in some cases this is treated as invested capital. See Maslov, Op. Cit., p. 191, and Bauer, Op. Cit., p. 142. However, what takes place here is not the production of new value, but only a redistribution of value produced earlier.
 As is stated by Oppenheimer and others. See Oppenheimer, Wert und Kapitalprofit, 2nd edition, 1922, pp. 69-70.
 [Rubin cites the Russian edition of the first volume of Capital, translated by V. Bazarov and I. Stepanov, 1923, p. 170.]
See Bohm-Bawerk,Op. Cit.
 See the Chapter on "Social Labor" above.
Rudolf Hilferding, Bohm-Bawerk's Criticism of Marx (published together with Eugen von Bohm-Bawerk, Karl Marx and the Close of his System), New York: Augustus M. Kelley, 1949, pp. 146-147.
 Maslov, Kapitalizm (Capitalism), p. 192.