(This is a draft. All comments welcome. Citations and footnotes are incomplete.)

Labor as Substance of Value

Once Marx has established that value is a property intrinsic to commodities he immediately goes on to ask what this value is and what determines the magnitude of this value. The answer to both questions is human labor time. Human labor creates commodities. The magnitude of labor (the time spent producing) determines the magnitude of the value of the commodity. Value itself is ‘objectified labor time’. That is, once a worker has produced a commodity this commodity represents, or ‘contains’, however many hours of past labor. This past, objectified labor is value. Objectified labor is the substance of value. Active human labor time determines the magnitude of this value.

Why is labor the substance of value? Marx’s argument is quite simple and short.

A commodity is a product of labor that has a use-value and an exchange-value. We know that exchange value is an expression of intrinsic value so exchange value cannot be the substance of value. Use-value also cannot be the substance of value. Use-values are heterogeneous and thus cannot be compared with one another. How do we compare the use of an apple to the use of a piano? There is no common denominator which we can reduce all uses to. Furthermore use-value has no quantitative properties, only qualitative ones. We cannot divide the usefulness of a piano in half or multiply it by 4. Yet we know value is a homogenous substance, that commodities with value share a common quality that can be divided, multiplied, etc. Value implies numerical relations between commodities.

Once we have excluded use-value and exchange-value Marx says that the only property of the commodity left is that the commodity is the product of human labor. In some ways this is a very simple and obvious argument since Marx has defined the commodity from the beginning as a product of labor that has a use-value and exchange-value. Since exchange-value and use-value cannot be the substance of value then the fact that they are products of labor is the only remaining attribute which can explain the value character of the commodity.

Many objections have been raised to Marx’s argument over the years. The great bulk of these critiques can be found in Bohm-Bawerk’s 1898 book “Karl Marx and the Close of His System”. Marx was not alive to address all of Bohm-Bawerk’s critiques. Let us see what we can do to remedy this here.

1. Bohm-Bawerk takes issue with the structure of Marx’s argument. Marx has defined a commodity as being a product of labor with a use-value and exchange-value. When he shows that use-value and exchange value cannot be the substance of value then only labor is left. Bohm-Bawerk argues that this is only possible because of the crafty way in which Marx defines ‘commodity’, sneakily leaving out other exchangeable goods which are not the product of labor.

“From the beginning he only puts into the sieve those exchangeable things which contain the property which he desires finally to sift out as “the common factor,” and he leaves all the others outside.” p70

“To exclude the exchangeable goods which are not products of labor in the search for the common factor which lies at the root of exchange value is, under the circumstances, a great error of method.” p70

“ his idea of “commodities” is narrower than that of exchangeable goods as a whole.” p71

BB is correct. Marx does not look at all exchangeable goods when he derives labor as the substance of value. He intentionally only considers commodities, which he defines as being useful objects produced by labor for exchange. This is because, contrary to some interpretations, Marx is not trying to explain the phenomenon of exchangeability or to explain prices. He is trying to explain the commodity. He says so very explicitly in the first lines of Capital: “The wealth of those societies in which the capitalist mode of production prevails, presents itself as “an immense accumulation of commodities,”[1] its unit being a single commodity. Our investigation must therefore begin with the analysis of a commodity.” (also cite Notes on Adolph Wagner and Kliman)

Marx’s topic is the commodity because the commodity is the basic unit of capitalist wealth. Commodity production, production for exchange, is the dominant form of production. This does not mean that commodity production is the only form of production, or that commodities are the only things that are exchanged. It instead means that commodity production dominates all other production and exchange. A common theme in Marx’s writing is the way in which value relations permeate and impose their logic on all other forms of social organization. This means that in order to understand our society we must first understand its most basic unit, the commodity and the value-form that it contains. Then we can examine the way the logic of the commodity effects other aspects of social organization.

Still, it seems we have not entirely disposed of BB’s critique. After all, Marx is saying that labor and only labor creates value in a capitalist society. Yet there are examples of things that have exchange-value that are not products of labor. How does Marx deal with this? He holds that not everything with an exchange-value has a value. This seems odd at first since we have said previously that exchange-value is the form of appearance of value. If a good has no value, is not the product of labor, what is its exchange-value measuring?

In fashioning a response a good place to start might be to try to name some exchangeable goods that are not a product of labor. Bohm-Bawerk asks us to imagine the products of nature: trees, land, minerals. But it is quite hard to distinguish between the product of nature and the labor that is required to turn these natural products into exchangeable goods. Trees must be cut and transported. Minerals must be mined, refined and transported. The only product of nature that seems able to have an exchangeability somewhat independent of human labor is the land itself. Land, of course, is hard to distinguish from the built environment that humans have produced. Much of the land is a result of the construction of spaces and transportation networks. So it is actually quite hard to have a theory of the exchange-value of land that is entirely divorced from a theory of production. At the same time there remains an aspect of land that is not directly produced for exchange. This aspect falls under the category of rent.

The theory of rent is a bit too complex to deal with in detail here, but a look at the basic contours of the theory will help us answer the question at hand. One plot of land is different from another and these differences constitute different resource endowments that convey productive advantages to the owners of land. As producers compete to produce below the socially necessary labor time in order to outsell rivals these difference in the productivity of land allow some sellers to produce below the socially necessary labor time thus obtaining a super-profit (see chapter on SNLT). This super-profit can be capitalized upon to become rent. Rent is a function of the relation of different productivity of the land to socially necessary labor time. Rent is a derivative category which we can only theorize once we understand value production. The price of land is related to rent. (Once one also considers other derivative forms of capital like credit, we can theorize other aspects of the exchange-value of land, as land becomes the focus of speculation and other credit-based investments.)

Land does not just have value by itself. Rent does not grow from the soil. The value of land, rent, is a product of the relation of land to the productivity of labor. Thus Marx’s exclusion of land from his analysis of commodities is entirely justified. Humans have worked on land for millennia. It is only in a capitalist society that land takes the form of private property that generates rent. If we want to understand the price of land we need to understand the wider social relations which generate this price form.

Later in Chapter 1 of Capital Marx explores the exchange of other non-produced goods:

“Objects that in themselves are no commodities, such as conscience, honour, &c., are capable of being offered for sale by their holders, and of thus acquiring, through their price, the form of commodities. Hence an object may have a price without having value. The price in that case is imaginary, like certain quantities in mathematics.”

(As an aside I find it amusing that Marx uses such strange examples of non-commodities here like conscience and honor. Clearly it is hard to find examples of non-produced exchangeable goods! Perhaps a modern-day example might be a politician who sells his “loyalty” to the capitalist class or an athlete who sells his “like-ness” to advertisers.)

In discussing rent we decided that rent was a derivative category of value production and that therefore Marx was justified in theorizing rent after he had formed a theory of commodities. Here we have a different matter, “imaginary value”. The first thing we might note is that since conscience and honor are not products of labor they are not freely reproducible and thus do not respond to the laws of supply and demand, or socially necessary labor time, the typical forces by which prices are established. This is a good reason to exclude them from the class of goods that we are considering since this sale of conscience or honor does not follow any predictable economic logic. Rather, the price of conscience or honor would be whatever the two parties of the exchange decide upon at the moment. We draw no further conclusions or laws from this. If we were to use these exchanges to construct a theory of value we would end up with an indeterminate, nihilistic theory of value in which values are merely whatever people decide they are in the moment, with no law-like regulation by the production process. (This is, of course, the direction that BB and his ilk would like to move value theory, into a nihilistic, hedonistic terrain where value is whatever an individual decides it is leaving us unable to make any theories about social structure, class, or production relations.)

But it is not the fact that we can deduce no laws from it that Marx excludes imaginary value from the central focus of a theory of value. Instead it is because such exchanges are an entirely irrelevant and peripheral phenomenon in our society. The nihilistic, indeterminate logic of “imaginary values” does not extend into the realm of commodity production. So there is no reason to bend the laws of commodity value to fit into the arbitrary whims of those who sell conscience and honor. On the other hand, the basic category of value (and money!) extends over all exchangeable goods. Because commodity production dominates all production and exchange, the exchange of “imaginary values” takes the form of commodity exchange, even though it is not commodity exchange proper. To win the loyalty of a Cardinal in medieval Europe a king would need ply the Cardinal with political favors. To win the loyalty of a politician in a capitalist society one must give her money. Thus the price of loyalty takes the form of commodity exchange even if it is not commodity exchange proper.

By “form of commodity exchange” I refer to a class society in which most people must buy their subsistence and sell their labor power in the market because they are divorced from the means of production. Labor is organized through commodity exchange and money stands as the universal measure of value. The exchange of products of labor take the form of market exchange. The exchange of non-produced things, like honor and conscience, also take the form of commodity exchange, even though they are not commodities.

Though BB does not bring up the topic at this point we might also mention the exchange-value of produced commodities that are not freely reproducible. A one-of-a-kind work of art like a Picasso painting is a commodity but it cannot be reproduced. Thus it does not respond to the pressure of socially necessary labor time. The exchange-value of a Picasso is a reflection of whatever someone is willing to pay for it at the moment, much like honor and conscience. Marx excludes non-reproducible commodities from his analysis for the most part as well since they are peripheral to capitalist production. However, like imaginary value, when we look at non-reproducible commodities we see that they take the form of commodity-exchange because that is the dominant form of social labor in our society.

2. BB’s second objections to Marx’s argument for labor as the substance of value is that there are other common properties to commodities other than being the products of labor.

“is there only one other property? Is not the property of being scarce in proportion to demand also common to all exchangeable goods? Or that they are the subjects of demand and supply? Or that they are appropriated? Or that they are natural products?….Why then, I ask again today, may not the principle of value reside in any one of these common properties as well as in the property of being products of labor” (BB p.75)

Since value is a social relation this means that we cannot look to natural properties (natural products) of commodities for a common property. Excluding their natural properties is the same as excluding their character as use-values since use-value is directly tied to the natural properties of the object. In addition, as Marx argues, there is no such thing as use in the abstract, as use-in-general, so use cannot be the common property we are looking for. There are only specific uses for things.

Certainly all commodities are scarce in proportion to demand. Is this a property of a commodity? When we buy a commodity are we purchasing a sum of scarcity? A sum of supply and demand? How can these be the substance of value? Here again we see what happens when BB conflates value and exchange value. Marx is certainly in agreement that supply and demand affect the formation of prices. Yet he does not believe this to have any relation to the determination of value. These cannot be the substance of value.

Ultimately, when it comes to society, human labor is the scarcity that matters. Society only has so many hours in a day to produce the commodities needed to reproduce itself. It must apportion these labor hours in such a way that shit gets done. Yes, there is a scarcity of natural resources as well. But this scarcity is measured in labor time! If it takes a million hours of labor a year to produce all the oil society needs then a million hours if the measure of the scarcity of oil.

3. BB’s third objection takes a different tack.

“Labor and value in use have a qualitative side and a quantitative side. As the value in use is different qualitatively as table, house, or yarn, so is labor as carpentry, masonry, or spinning.”p76

Marx has said that use-value can’t be the substance of value or the determination of its magnitude because use-value is not homogenous. We cannot compare one use-value to another. Just as use-values are heterogeneous so too are the labors that create these use-values. The labor that creates apples is not the same as that which creates pianos. How can we equate the two? What makes them a common substance? Isn’t Marx using one argument to dismiss use-value and then ignoring the same argument when it comes to labor?

It may seem that BB has come up with a clever retort here unless we realize that Marx himself poses this same question in the first chapter of Capital. “As the coat and the linen are two qualitatively different use values, so also are the two forms of labour that produce them, tailoring and weaving.”

Notice however that Marx does not say here that the labors are qualitatively different in any and all senses. Rather he says they are qualitatively different as the coat and linen are different use-values. The aspect of human labor that accounts for the different qualitative use-values is “concrete labor”, heterogenous labor unique in the motions, skill and knowledge specific to apple growing or piano making. Yet despite these specific, concrete differences all labor is also human labor in general, or “abstract labor”. As will be discussed further in the chapter on abstract labor, labor is both concrete and abstract at the same time. As concrete labor it is heterogeneous, differentiated. As abstract labor, it is part of the total labor expended by society, the same as all other labor in the sense that it is a function “of the human organism, and that each such function, whatever may be its nature or form, is essentially the expenditure of human brain, nerves, muscles, &c.” (from fetishism section of Chapter one.)

So even though labors are different these different labors are all just examples of labor in general, of labor in the abstract. If Marx can make this concrete-abstract distinction with labor why not also for use-value or utlity? The answer is simple: there is no such thing as use in general. Uses are only concrete, specific to the commodity and the way it is used. [footnote]

But isn’t the fact that we have the word “use” that applies to both apple eating and piano playing evidence that there is a concept of ‘use in general’? A ha! This question brings us to the heart of what is really interesting and important about Marx’s concept of abstract labor. The word ‘use’ is a category which encompasses all specific types of using just as the word ‘labor’ is a category that encompasses all specific types of labor. However Marx is arguing that abstract labor is not just a theoretical abstraction, not just a handy linguistic device for tying together heterogenous concrete actions. Instead abstract labor is a real entity existing in capitalist society.

This is covered further in the chapter on abstract labor however the basic line of argumentation is this: There are multiple forces in a capitalist society that reduce human labor to an abstraction, a pure expenditure of physiological labor. Socially necessary labor time reduces all labor to its maximum output so that all labors everywhere are valued the same, that is, they are all labors producing at maximum efficiency. We can compare the labor of apple pickers to piano makers because both are human labor expended in its most efficient form. Capital of course has no care for the specific use-values it creates and therefore no care for the concrete labor that produces them. It only cares about value production, value in general. Thus capital treats all labor as abstract units in a giant profit calculator. Whether this labor produces apples or pianos or rubber ducks makes no difference as long as it is working at maximum efficiency. For this reason workers in a capitalist society have a much higher degree of subjective indifference to their work than in past societies. People move from job to job with much more flexibility than in, say feudalism where one was born into a caste and worked in the same capacity for life. Etc….

Thus Marx can say that labor is the substance of value because labor is both concrete and abstract at the same time.

Part Two: Other arguments

Setting aside BB’s objections it should be noted that some folks, Marxists included [Rubin for example], have not always found Marx’s above argument satisfactory enough to not need additional argumentation. Marx’s argument has the flavor of an analytical proof (a commodity is x, y and z. Since x and y can’t explain value then it must be z.) and such forms of argument don’t always sit well with folks. Andrew Kliman has advanced a very thorough defense of Marx’s argument (see “The Fourth Thing on the Third Thing”) which there is no need to repeat here. However, when something is true there are often multiple ways of knowing or explaining why it is true, so it does no harm to examine other arguments that have been put forward to defend the idea that labor is the substance of value.

Humans and Robots

Human labor most often uses tools or machines or even robots in the course of doing work. These machines allow us to be more productive. In a sense machines ‘do work’. But is this work the same as human labor? Many have argued against Marx by claiming that machines labor just as humans do (see Sraffa, Keen, etc.). This has led to discussions as to what specifically is so unique about human labor. Why is human labor the substance of value but the work done by machines, or even nature for that matter (like when the apple tree does the work of growing an apple) is not considered the substance of value? [insert footnote as to how the dead-labor in machines is transferred to the product.]

We use machines to make our labor more productive. Productivity is a measure of the amount of use-value created in a span of time. Since, for Marx, value is determined by labor time an increase in productivity (in use-values) does not create a corresponding increase in value. The same amount of value is created, just spread out over a larger quantity of use-values. This difference between use-value production and value production is one of the hallmarks of Marx’s theory of value. It allows Marx to explain many of the most important contradictions at the heart of capitalism: the domination of living labor by dead labor, the tendency of the rate of profit to fall, ETC. This also explains why unit prices tend to fall as productivity rises. If we were to argue, contrary to Marx, that machines create value then we wind up with a theory in which use-value production is the same as value production. An increase in productivity would mean an increase in value-production. This results in a very different theoretical understanding of the economy. Such an understanding cannot derive any of the same contradictions that Marx’s theory does. There is no tendency for the profit rate to fall with rising productivity, living labor is not dominated by dead labor, profit doesn’t come from exploiting workers, and prices do not fall with rising productivity.

Merely pointing to the different implications of these two perspectives is not some proof that labor is the substance of value. In the search for ‘proof’ defenders of Marx’s value theory have sometimes tried to point to the unique properties of human labor, properties that machines do not have. Marx himself makes reference to the unique properties of human labor in a famous passage: “But what distinguishes the worst architect from the best of bees is this, that the architect raises his structure in imagination before he erects it in reality. At the end of every labour-process, we get a result that already existed in the imagination of the labourer at its commencement. He not only effects a change of form in the material on which he works, but he also realises a purpose of his own that gives the law to his modus operandi, and to which he must subordinate his will.” [capital chapter 7]

With each successive revolution in robotics more and more types of activity are removed from the list of “exclusive human activities”, leaving less and less options for those who want to point to an essential aspect of human labor that differentiates it from machines. In the above passage Marx brings out probably the most essential difference between human labor and the work of machines: that the worker imagines the product and process before she commences production. However, in this age of rapid advances in computing and artificial intelligence I believe it is dangerous to hinge our argument on an aspect of human work that is directly under attack by the artificial intelligence industry. I think it is much more fruitful to find a unique property of human labor that holds even if robots one day can do every task that humans can do.

Caffentzis makes, in my opinion, the only possible argument: “if labor is to create value while machines do not, then labor’s value creating capacities must lie in its negative capability, its capacity to refuse to be labor.” [“Why Machines Cannot Create Value” Caffentzis 1997 in “Cutting Edge” ed. Jim Davis] In other words, what makes humans different than machines is that humans can refuse to work. This makes human labor a social relation. Humans must be coerced/convinced to do work. They do not operate like machines that can be just turned on and off. This distinction brings out the coercive side of value relations. Feudal society had knights and the Catholic Church to make the serfs work the land. Capitalism has value relations which are their own form of coercion.

Of course if robots ever evolved to the point in which they could refuse to work then their work would also become a social relation and thus would be value creating. Of course, if this ever happens we might have more important problems on our hands…

Production as the Dominant Moment

Marx’s argument for labor as the substance of value is often placed, quite rightly, within the context of his wider historical method which treats the organization of production relations as the central defining aspect of all societies. It is argued that since the organization of human productive activity is the defining aspect of all societies, and since the production of value is the specific form of organization this takes in a capitalist society, that the substance that capitalist labor produces is value. [cite Rubin? Hilferding?]

The organization of human social relations is not handed down to us by God. It is something we actively create and recreate each day. In an obvious physical sense our labor produces food and other necessities needed to continue our daily physical existence. But our labor also reproduces the social relations within which we live. When a feudal peasant produces surplus grain for the landlord they are reproducing the class relations of feudal society. So too do workers in a capitalist society reproduce capitalist class relations when they produce surplus value for the capitalist class. And this is not all that workers produce. Everything from the built environment, to the means of subsistence, to the forms of entertainment and diversion are creations of human labor, creations that must continually be reproduced in order to reproduce capitalist social relations. Marx sees this creative power as central to the organization of society. Other aspects of social organization like state forms, ideology, family, distribution, etc derive their character through the fact that they exist within a society organized by capitalist social relations. Capitalist states can, of course, take different forms, but they are all various forms of the capitalist state. Capitalist ideology can take different forms but they are all various manifestations of capitalist ideology. Their essential character is defined by their relation to the mode of production.

This way of looking at society is often criticized as ‘reductionist’. There are many forces that act upon and shape a society. What right does Marx have to privilege one aspect, production, above other aspects?

In his online lectures on Capital David Harvey gives this defense: “My own view of it is that it is an inspired idea but, like most reductionist arguments, ultimately it fails. But by taking that reductionist position you start to see all kinds of things you would not otherwise see. And without that reductionist impulse Marx would never have understood all manner of things.” After a brief aside about reductionism in the biological sciences he goes on to say, “…the very search for reductionism has produced very important insights in the biological field in exactly the same way that I would argue that Marx’s holding to principles of reductionism here plays a very significant role in his method of inquiry, in his compulsion to inquire. And one of the things I get annoyed at is people who say ‘Oh it’s reductionist therefore don’t believe it!’ If people were not prepared to be reductionist about things we would hardly know anything about anything.” (Reading Capital with David Harvey Class 2)

Regardless of whether one agrees with Harvey’s characterization of the issue this is a rather weak defense of Marx’s method. For Harvey Marx’s placement of production at the center of social relations is not an accurate representation of reality. It is merely an inspired viewpoint that allows us to generate interesting insights. Such criteria could justify any method of reduction if it generated an interesting insight. For our purposes here, justifying the argument that labor is the substance of value by appealing to the role of production as the central category in all societies, Harvey’s argument is even more useless. We are trying to justify the results of the method by showing the legitimacy of the method. Harvey is trying to justify the method by showing the legitimacy of its results. It is hard to justify the means by the ends in social theory. Is a faulty form of argumentation justified because the conclusions conform to our preconceived political opinions or because they paint a picture of the world that helps us ‘make sense of things’? No doubt people often do appeal to this type of justification but this cannot be an adequate framework for a radical theoretical project to critique and transform capitalism.

When we consider the relation of production to distribution, consumption and exchange it is easy to seem caught up in an endless game of ‘chicken and egg’. For example, production produces the objects we consume but consumption, or the need to consume, is the force which triggers the need to initiate production. How then does Marx have the right to claim that “production is the real point of departure and hence also the predominant moment”? (Grundrisse p.94) Marx is certainly aware of the ways in which production is informed by consumption, exchange and distribution, yet he insists that production is the dominant moment.

I believe that the best answer is to consider the alternatives. What would it mean to define capitalism as a ‘mode of consumption’ rather than a mode of production? What would a mode of consumption be? Just as there is no ‘use in general’, no ‘use in the abstract’, there is no general mode of consuming by which we can classify all of the consumptive activities of a capitalist society. We only have specific ways of consuming. Furthermore these are not social relations but relations between individuals and objects. The only aspect of consumption which can apply to all consuming activity is that most consumption in our society is consumption of commodities. This, however, is a definition that requires an understanding of commodity production. It is commodity production that stamps capitalist consumption with its unique character.

This same argument could be carried out in relation to exchange and distribution. To the extent that we can define a specifically capitalist mode of exchange it is commodity exchange. [Footnote on distribution. Tie in to the point earlier on about commodity relations dominating other relations. Follow Marx’s argument from intro to Grundrisse.]

Empirical evidence

There is a long history of debate about whether or not Marx’s theory of value can be empirically confirmed. Depending on how one understands the theory attempts to prove or disprove the theory empirically take different approaches. This is not the place to evaluate all of these. However a few points can be made that should help clarify the issue.

One of Bohm Bawerk’s chief complaints against Marx is that Marx ignores empirical evidence that contradicts his theory of value. BB argues that Marx himself contradicts his own theory of value laid out in volume one of Capital when later in Volume 3 he develops the theory of ‘prices of production’. I explain ‘prices of production’ in the chapter ‘Value and Price’. For now all that needs to be said is that in the theory of prices of production Marx shows how prices systematically deviate from values in the context of competition between capitals. BB sees this as an admission by Marx that in reality prices deviate from values. He takes this to be an empirical counter-factual that brings into question why labor should be the determinant of value.

BB makes repeated claims that Marx began with one theory of value and then later changed his mind when writing volume 3. We now know that Marx actually penned much of volume 3 before beginning work on volume 1. Marx was completely aware of the systematic deviation of prices from values when he introduced the concept of labor as the substance of value in the opening chapters of Capital. Clearly, to Marx, there is no contradiction between value and prices of production. Why does BB see things differently?

The answer to this question lies in the fact that BB is quite confused as to what value is in the first place. BB has conflated value and price. He thinks that Marx is arguing that the magnitude of price is determined by labor time. Thus if there is a systematic deviation of value and price this shows that other factors influence the magnitude of price. Therefor labor time cannot be the exclusive determinant of price.

However this is not Marx’s theory of value at all. Prices of production are prices which deviate from values (the commodity bears a price that is more or less than the labor time that entered into its production.) However prices of production are still a sum of value.

If I trade an apple pie worth 1 hour of labor for a piano worth 100 hours of labor I have sold my apple pie for far above its value. However both apple pie and piano are sums of value. The reason we can say that the exchange was an unequal exchange is because we know that both commodities have a value outside of their exchange value. Price is just a special form of exchange value, the exchange value of any commodity with the money commodity. If I trade my apple pie with money representing 100 hours of labor time then the same unequal exchange has taken place. And, once again, both the apple pie and the money represent sums of value.

If Marx had merely said that labor time is the primary determinant of commodity values then we could easily prove or disprove his theory with empirical studies of prices in relation to labor inputs. But Marx’s argument that labor is the substance of value is a different beast entirely. All money prices represent sums of value. These prices can be above or below the actual labor content of a commodity. This can happen through unequal exchange. It can happen through imbalances of supply and demand. And this happens systematically with prices of production. Regardless, none of these deviations stop prices from being sums of value or stop labor from being the content of this value.

What then can be done to empirically verify Marx’s theory of value? I do not believe there is any knock-down empirical proof that labor is the substance of value. However, the argument that labor is the substance of value suggests several tendencies/phenomena that can be empirically judged, to an extent. For one, even though prices systematically deviate from values this is a systematic deviation. They do so in a predictable way. This means that there are still correspondences between value and price. The chief correspondence is the fact that a decrease in labor time per unit produced (increases in efficiency) leads to falling unit prices. This is a prediction based on Marx’s theory of value and it is a prediction that is quite obviously borne out empirically again and again. Everyone is aware that commodity prices fall as labor becomes more productive.

Another phenomenon suggested by Marx’s theory of value is the ‘tendency of the rate of profit to fall’, a subject which has its own chapter in this book. If only human labor produces value then we would expect profit rates to fall when capitalists invest more in non-human inputs (machines, raw materials) than living labor. There is quite a lot of debate about the extent to which empirical evidence supports this theory. As with any empirical debate the devil is in the details. There are quite a lot of different factors involved in measuring profit rates, and even greater difficulties when it comes to showing any causality investments in living labor relative to machines and profit rates. It may be that the present state of record keeping and number crunching is in adequate to properly adjudicate Marx’s value theory through an empirical study of profit rates.

[footnote on Kliman’s position on whether his work ‘proves’ the TRPF]

Conclusion.

The role of labor as the substance of value, and of labor time as the determinant of the magnitude of value, is one of the most controversial aspects of Marx’s work. At the same time it is one of the most crucial. Without a theory of value Marx could not have explained the phenomenon of surplus value which defines the class relation between capitalists and workers. Without a theory of value Marx would not have been able to understand the role of money in capitalism and to argue against the money-reformers of his time. Without value theory Marx would have been unable to theorize the recurrent crisis tendencies of capitalism. The list goes on and on. Value theory sits in a central place in Marx’s universe of thought.