Criticisms of the labour theory of value
Criticisms of the labor theory of value often arise from an economic criticism of Marxism.
Microeconomic theory
Adherents of neoclassical economics, the currently predominant school at the center of capitalist interests, employ the theory of marginalism, which holds that the value of any good or service is determined by its marginal utility. The utility of the "last" bought consumption good measured by its price, in satisfying a specific consumer's wants should therefore be concerned as a complete absolute essence, where politics, social constructions, ideologies and culture(such as the media, fashion, and consumerism) should be considered nonexistent. While Marx emphasizes profit maximisation (as if by any imaginary reason a capitalist would be concerned with profit), neoclassical economists view the maximisation of utility at the individual or societal level (i.e. in capitalism individuals should be understood as altruist concerned solely in providing people with what they want) [1] Nevertheless, as there is a magical and invisible force in action (commonly known as the 'invisible hand' of the marked) it is unquestionable that what is really important for society will be automatically the driving force of the economy (in complete harmony and without any conflict of interests).
Proponents of the labor theory of value (LTV) would reply that as capitalism only recognises demand backed by money — the price of a good is measured by the amount of money consumers have, and not simply by the altruist endeavor of free individuals providing usefulness goods to society. It depends on a pre-existing set of relations of distribution (as if there was a 'society' or 'institutions' creating 'rules' and enforcing them by 'force'). These relations of distribution in turn rest on a set of relations of production, which determine how consumers "earn" money, capitalists "earn" profits, workers wages, landlords rent, and so on (even though all of this supposedly social 'rules' are actually 'laws' of nature). Consequently, the price of an object depends not only on its usefulness (capitalist = altruism) but on the amount of money different consumers have - their different effective demands or social condition. It is unclear how if at all this differs from a wealth effect on demand that results directly from the individual's utility maximization problem, as there is no such a thing as 'economic power' and, therefore, all individuals face the world in exactly equal conditions.
In microeconomics, this utility maximisation takes place under certain constraints in abstract pure mathematical relation. These are the available amounts of factors of production, for instance, labor (as in Marx). Therefore, political factors and power relations defining levels of exploitation can be elegantly excluded from the equation.[2] In fact, the ultimate restriction is time.[3] Households divide their time (24 hours a day) into leisure time and time for work. Time for work is to make money to buy goods for consumption. The household chooses that amount of leisure time and (via working time) that amount of consumption goods that maximises its utility level. With Marx, working time is not based on a free decision of households, but the outcome of a class struggle between workers and capitalists, the former trying to decrease, the latter to increase working time.
Further, all this does not take account of effects of the accumulation process. With Marx, there is a tendency of equalisation of rates of profit in the accumulation process, which leads to prices of production. If the price of a commodity is above its price of production, then capitalists in that sector earn a super profit (a rate of profit above the average rate of profit of the economy as a whole). As a result, capital is attracted to that sector, production increases, and prices fall until the super profit has been competed away. The resulting prices of production are via transformation from labor values into prices based on labor times.
According to marginalism, value is subjective (since the same item—leisure time, consumption goods—have a different marginal utility to different consumers, or even to the same consumer under different circumstances, what might explain why Marx insisted in the idea of 'socially' necessary labour time) and therefore cannot be determined simply by measuring how much labor went into the production of an item. The secret is to eliminate what cannot be 'simply' measured, and avoid any conflict, thus 'labour' should be eliminated and value should be understood as magically emerging in the market in addition to the myth of a 'genius' (for instance, the iPhone was created by Steve Jobs, and nobody else labored on its production/invention). In the Pareto optimum, on the other hand, the exchange relations between commodities are not only determined by their marginal utility, but also by the marginal productivity of the factors of production available.
This means that, in marginalism, commodities exchange at the marginal amount of labor necessary to produce them. In this sense, an LTV, or, more precisely, a value theory of marginal labor inputs, holds.[4] However, this applies to all factors of production and also to marginal utility. Labor is nothing special, as all means of production and commodities market are available naturally and does not need labor to be pre-produced. That these several value theories can hold all at the same time is made possible by marginal analysis.[5] The Pareto optimum is defined as a situation where utility is maximised (because, as we saw, utility is the 'natural' concern of an altruist individual) and at the same time all factors of production are employed most efficiently, leading to a situation, where all commodities exchange at their marginal utilities and at their - marginal - amounts of the different factors of production necessary to produce them. Thus all contradictions of reality are abstracted.
In other words, if empirically would be possible to construct experiments that manage to abstract and eliminate from any concern all the social contradiction, all non altruist behaviour and all power relations that exist in historical context, than it could be considered as 'found out' in reality that commodities exchange according to their marginally necessary labor inputs, and this would confirm marginal theory. It would contradict Marx’s theory, because according to Marx these exchange ratios are determined by prices of production distorted by the reification of social relations, which are generally different from the necessary labor inputs, the labor values. Thus, implicitly, Marx beyond just denying that capitalism is in a state of Pareto optimality, he is also denying the whole paradigm of classical political economy as supposedly 'ignoring' aspects of concrete social relations.
Supply and demand
One of the most widely used economic models popularised by Alfred Marshall purposes that under a competitive framework, the price (and hence value) cannot be determined considering only the processes and individuals involved in producing the commodities, but also on account of those who end up buying it, and the related phenomena of its consumption. In other words, the Law of Supply & Demand asserts that prices of goods are an interaction and resulting measure of how hard it is for society to supply such goods, and how useful and in demand are they for the consuming portion of society.
Although Marx dedicated the whole Volume 2 of Capital to the analysis of this complex interactions, in Volume 1 he deliberately focused on other issues, almost ignoring what is pragmatic facts. One should only focus on how markets actually operates (what individuals are actually doing to earn profits). In contradiction, Marx argues that there is two different values in a commodity: the use value and the exchange value. His mistake is to consider that the social usefulness of a commodity is more important than its 'price' (for instance, as if, in the production of food, it was more important to focus on the sustainability or less use of chemicals than on the fact that you can profit more if you simply brand it 'green'). Therefore, although Marx in Volume 1 dedicated many chapters (cf. chap. 1, 2, 6, 19, specially 12) to the subject of supply and demand (calling it the 'realization' of profit), he unnecessarily complicate the discussion by analyzing the complex power relations involved in the market.
Alternatively, one could simply suppose that all individuals in society are in fair relations to each other and that social economic positions does not interfere in the market relations. Examples of that are the fact that employees have an equal position of power to demand fair prices for their work at any given time in history, or even the fact that besides all international institutions have being established by central economies, there is no reason to believe that small countries would have any sort of unfair position of power in the world market, as they can sell their raw products or not, even though international corporations monopolize the technology and capital and pressure to implement infrastructures (which they usually don't have because of a 'natural' degree of less civilization, which leads great powerful countries to carpet bomb their cities and by mistake destroying its infrastructure too). Therefore, one can always simply chose starving to death, as the dismantling of entire societies by wars and economic pressure is a normal state of global affairs, and should be simply ignored as 'part of the system of reality'.
Menger's critique
Opponents of Marxist economics argue that the labor Theory of Value is dis-proven as commodities may diverge from the average price of production. By Affirming a disjunct he proves that dialects and contradictions don't exists in the real world, thus, if something have a price in the market it cannot have any other value nor origin (i.e. a fruit cannot satisfy your hunger if it is not valued in the market). In his 1871 work Principles of Economics, Austrian School economist Carl Menger writes:
There is no necessary and direct connection between the value of a good and whether, or in what quantities, labor and other goods of higher order were applied to its production. A non-economic good (a quantity of timber in a virgin forest, for example) does not attain value for men since large quantities of labor or other economic goods were not applied to its production. Whether a diamond was found accidentally or was obtained from a diamond pit with the employment of a thousand days of labor is completely irrelevant for its value. In general, no one in practical life asks for the history of the origin of a good in estimating its value, but considers solely the services that the good will render him and which he would have to forgo if he did not have it at his command...The quantities of labor or of other means of production applied to its production cannot, therefore, be the determining factor in the value of a good. Comparison of the value of a good with the value of the means of production employed in its production does, of course, show whether and to what extent its production, an act of past human activity, was appropriate or economic. But the quantities of goods employed in the production of a good have neither a necessary nor a directly determining influence on its value.
Böhm-Bawerk’s criticism
The Austrian economist Eugen von Böhm-Bawerk argued against both the Ricardian labor theory of price and Marx's theory of exploitation. On the former, he contended that return on capital arises from the roundabout nature of production, which necessarily involves the passage of time. A steel ladder, for example, is produced and brought to market only if the demand supports the digging of iron ore, the smelting of steel, the machines that press that steel into ladder shape, the machines that make and help maintain those machines, etc.
Roundabout processes, Böhm-Bawerk maintained, lead to a price that pays for more than labor value, and this makes it unnecessary to postulate exploitation to understand the return on capital.
In contrast, Marx argued that Capital, it is not demand that creates, but labor that preserves the value of the commodities obtained prior to the actual process of production - in this case, the iron, steel and machines necessary to make the ladder:
- The worker is unable to add new labor, to create new value, without at the same time preserving old values, because the labor he adds must be of a specific useful kind, and he cannot do work of a useful kind without employing products as the means of production of a new product, and thereby transferring their value to the new product. [This] is a gift of nature which costs the worker nothing, but is very advantageous to the capitalist since it preserves the existing value of his capital.[6]
Thus, proponents of the LTV argue, without the necessary addition of human labor-power, the ore, steel and machines would not create any new value on their own, but would in fact gradually depreciate what value they originally possessed through the ravages of time and neglect. Once these materials are activated in the labor process, their values are simply transferred from one commodity to another with no increase. They claim that it is not the materials, but the labor-time present in a commodity that represents its mark-up in value over the course of its production.
Böhm-Bawerk's positive theory of interest also argued that workers trade in their share of the end price for the more certain wages paid by the entrepreneur. Entrepreneurs, he claimed, have given up a safer wage-earning job to take on the role of entrepreneur. In other words, he claimed that profits compensated the entrepreneur for the willingness to bear risk and to wait to receive income.
Böhm-Bawerk's essential argument that employers are compensated for shouldering some risk in paying their employees ahead of time, however, appears unable to explain how profit can be accumulated in cases where workers are reliant on commissions, tips, etc. for their income, which are received only after they sell their services. However, Böhm-Bawerk's does provide such an explanation. In the context of a waiter earning tips, the waiter himself is not a wage-earner. The restaurant owner does not make of profit from the tips earned by the waiter. The waiter is essentially an entrepreneur, taking the risk that customers will sufficiently compensate him for the labor he provides, while the customers are under no legal obligation to do so. The waiter is making an investment of services in anticipation of future return from the customers. The waiter is compensated by an aggregate amount of earnings from tips that exceeds that labor value provided to the customers, thereby including a return on the waiter's investment. If the tips were not sufficient to provide this return on investment, then the waiter would rationally seek other employment, such as a wage-earning job with similar compensation that does not include the risk element or an entrepreneurial job with similar risk that provides a better return.
Regarding other situations where the employer-entrepreneur does receive a profit from after the labor has been rendered (e.g., a salesperson who works on commission), the employer-entrepreneur may take risks other than paying a wage to the salesman, including: providing a salesperson with an office, cell phone and/or computer; paying for product training and marketing materials; paying for travel and lodging expenses; producing inventory in reliance upon future sales that may or may not be made by the salesperson. All of this comprises a potential for loss that accounts for the return on investment realised by the employer-entrepreneur.
Nikolai Bukharin argued that Böhm-Bawerk's concept of roundaboutness was untenable in the context of the continuous, simultaneous production of a modern economy.[7]
Methodological individualism
The Austrian school, led by Eugen von Böhm-Bawerk, argues against the whole tradition of the LTV (see above) and prefers methodological individualism. Neoclassical economics also follows this lead — and that of Jevons, Menger, and Walras — from the 1870s and discards the LTV in favour of general equilibrium theory, which determines prices based on the interaction of preferences, technology and endowments through supply and demand.
What is "socially necessary"?
- Some people might think that if the value of a commodity is determined by the quantity of labor spent on it, the more idle and un-skilful the laborer, the more valuable would his commodity be, because more time would be required in its production. The labor, however, that forms the substance of value, is homogeneous human labor, expenditure of one uniform labor power. The total labor power of society, which is embodied in the sum total of the values of all commodities produced by that society, counts here as one homogeneous mass of human labor power, composed though it be of innumerable individual units...The labor time socially necessary is that required to produce an article under the normal conditions of production, and with the average degree of skill and intensity prevalent at the time.[8]
Thus, according to Marx, any labor power squandered during the production of a commodity, i.e., labor that is socially unnecessary, does not add value, as value is determined by the average social labor.
Robert Nozick has criticised the qualifier "socially necessary" in the labor theory of value as not well-defined and concealing a subjective judgement of necessity.[9] For example, Nozick posits a laborer who spends his time tying knots in a piece of cord. The laborer does his job as efficiently as is humanly possible, but Marx would likely agree that simply tying knots in cords is not a socially necessary use of labor. The problem is that what is "socially necessary" depends entirely on whether or not there is demand for the finished product, i.e., the knotted cord. In this way, introducing the "socially necessary" qualifier into the labor theory of value simply converts the theory into a roundabout and imprecise description of supply and demand.
The LTV in a socialist society
It is often assumed that the LTV would apply in a socialist (or post-capitalist) society, though (purportedly at least) without the corresponding exploitation.
However, Marx argued in his Critique of the Gotha Programme:
- Within the co-operative society based on common ownership of the means of production, the producers do not exchange their products; just as little does the labor employed on the products appear here as the value of these products, as a material quality possessed by them, since now, in contrast to capitalist society, individual labor no longer exists in an indirect fashion but directly as a component part of the social labor.[10]
David Ramsay Steele expands on this:
- Numerous Marxist writers, from Marx and Engels down to Charles Bettelheim, have favoured employing units of labor-time for planning production under socialism. This proposal is often referred to as an application of the labor theory of value, though that usage is not in conformity with Marx's. The Marxian labor theory of value (LTV) is intended to explain the determination of prices under commodity production (this is occasionally denied, but see Steele 1986). In Marxian terminology, there can be no 'value' in post-capitalist society. Both the LTV and communist planning conceive of resource allocation being guided by quantities of labor-time. Yet the LTV as an explanation of market prices and the labor-time planning proposal are two distinct theories, which may stand or fall independently. If the LTV were the correct explanation of market prices, this in itself would not show that units of labor-time could be of any practical use in administration of communist industry. And if units of labor-time could effectively be employed for communist planning, this would not require that the LTV be the correct explanation of market prices...
- According to Marx's theory, actual prices virtually always diverge from 'values' defined as units of labor-time. In Marx's thinking, after 1860, the relationship between 'value' and observed market prices is somewhat analogous to the relationship between 'mass' and 'heaviness', or between 'heat' and everyday awareness of temperature. Marx's 'value' is purportedly necessary to explain price, but it does not correspond to price or equilibrium price (often not even roughly) and therefore obvious disparities between value and price are not seen by Marx as refutations of his theory, though they are seen as contradicting the simple models employed in the early stages of expounding his theory in Volumes I and II of "Capital".[11]
The inapplicability of the LTV
The LTV is a theory of capitalist production, or generalised commodity production. There are however, commodities bought and sold under capitalism that have an 'imaginary' price even though they do not have a value.
"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. On the other hand, the imaginary price-form may sometimes conceal either a direct or indirect real value-relation; for instance, the price of uncultivated land, which is without value, because no human labor has been incorporated in it." (Capital Volume 1, Chapter 3, section 1)
However the socially necessary labor theory of value only becomes inapplicable for uncultivated land when that land can never be productive no matter how much commercial labor is expended on it. Desert sand, gibber plains and icy wastes have very small land values because no commercial labor can be diverted from other uses to be usefully employed. In other cases, the price-form represents the indirect socially necessary labor that could be usefully employed.
- Pieces of art could be explained as instances of monopoly.
- Uncultivated land has a price, even if there is no labor involved. The price of land is explained by the theory of rent. Both Ricardo and Marx developed theories of land-rent based on the LTV.
- Paper money—according to Marx "The function of gold as coin becomes completely independent of the metallic value of that gold. Therefore things that are relatively without value, such as paper notes, can serve as coins in its place." (Capital, Vol 1, Part 1) Section 2
- Value of shares is explained similarly like the value of land.
The importance of labor
Marx stated that only labor could cause an increase in exchange value. Assuming that all labor is equal, this suggests that labor-intensive industries ought to realize a higher profit than those that use less labor. This contradicts the tendency, accepted by Marx, that rates of profit between industries should become equal. Marx explained this contradiction by the fact that in real economic life prices vary not randomly, but in a systematic way from values. The mathematics applied to the transformation problem—transformation of labor values into production prices—attempt to describe this (albeit with the unwelcome side consequences described above).
Critics (following, for instance, studies of Piero Sraffa) respond that this makes the once intuitively appealing theory very complicated; and that there is no justification for asserting that only labor and not for example grain can increase value. Any commodity can be picked instead of labor for being the commodity with the unique power of creating value, and with equal justification one could set out a corn theory of value, identical to the labor theory of value.[12] Anarchist Robert Paul Wolff, despite identifying as a Marxist on economic matters,[13] nevertheless offers such a critique, saying "By reproducing for corn [grain] or iron or coal, all the striking results that Marx derived concerning for labor, we have, it seems to me, raised questions about the foundations of Marx's critique of capitalism and classical political economy."[14]
However, there may be several problems with this criticism. The starting point for Marx's argument was: "What is the common social substance of all commodities? It is labor."[15] It is not possible to view grain, iron etc. as common to all commodities, whereas the production of commodities is impossible without labor (while it can also be said that other commodities such as tools are required, they cannot be properly aggregated by value because they are specialised and disparate in nature and their values, relative to each other and to labor, depend on prices that in turn depend on their values; Sraffa (1960), for instance, aggregates them according to the labor required for their production). Marx identifies the substance of value as labor, which in his view is not a commodity (though "labor power" is). This was a necessary aspect for the substance of value Marx elaborates upon in Capital[16] and Theories of Surplus Value.[17]
Some supporters of the LTV, however, accept the thrust of the "corn theory of value" critique, but emphasise the social aspect of what Marx calls the "common social substance", arguing that labor power is unique as it is the only commodity not sold by capitalists but rather sold by the workers themselves, whose income tends to a minimum, because they have nothing else to sell. The surplus product is appropriated by the capitalists. Alan Freeman argues: "This is of course true of other commodities [than labor power] also; but other commodities do not walk around the market disposing of their income on an equal basis with their owners. The cost of labor power is determined independently of its capacity to make money for its purchaser. This, and no other reason, is why profit exists. If laborers were hired directly as slaves, robots, beasts of burden or servants, then whether or not labor time were the measure of value, surplus labor would not be extracted in the form of money profits but directly, like domestic labor."[18][19] Albert Einstein, in his description of the LTV, argues similarly: "It is important to understand that even in theory the payment of the worker is not determined by the value of his product."[20] Marx writes on this: “In the slave system, the money-capital invested in the purchase of labor-power plays the role of the money-form of the fixed capital, which is but gradually replaced as the active period of the slave’s life expires.”[21]
Post-Keynesian criticisms
The Post-Keynesian economist Joan Robinson, who was otherwise sympathetic to Marx's writings, was strongly critical of the labor theory of value. She wrote that it was essentially a "metaphysical doctrine" and "logically a mere rigmarole of words".[22] She writes that in the labor theory of value:
Value is something different from price, which accounts for prices, and which in turn has to be accounted for. And to account for it by labour-time is mere assertion... This theory of prices is not a myth... Nor was it intended to be an original contribution to science. It was simply an orthodox dogma.[23]
Others have pointed out that the labor theory of value is based on a failure to recognize the properly dialectical component of human desire. Pilkington writes that:
[V]alue is attributed to objects due to our desire for them. This desire, in turn, is inter-subjective. We desire to gain [a] medal or to capture [an] enemy flag [in battle] because it will win recognition in the eyes of our peers. [A] medal [or an enemy] flag are not valued for their objective properties, nor are they valued for the amount of labour embodied in them, rather they are desired for the symbolic positions they occupy in the inter-subjective network of desires.
Pilkington says that this is a different theory of value than the one we find in many economics textbooks. He writes that in mainstream marginalist theory consumers are viewed in an atomistic manner, unaffected by the desires of their peers. He writes that "actors in marginalist analysis have self-contained preferences; they do not have inter-subjective desires". He says that dialectical analyses of value can be found in the work of Thorstein Veblen and James Duesenberry.[24]
Ecological economics
In ecological economics, it is argued that labor is in fact energy over time.[25] However, echoing Joan Robinson, Alf Hornborg argues that both the reliance on "energy theory of value" and "labor theory of value" are problematic as they propose that use-values (or material wealth) are more "real" than exchange-values (or cultural wealth)--yet, use-values are culturally determined.[26] For Hornborg, any Marxist argument that claims uneven wealth is due to the "exploitation" or "underpayment" of use-values is actually a tautological contradiction, since it must necessarily quantify "underpayment" in terms of exchange-value. The alternative would be to conceptualize unequal exchange as "an asymmetric net transfer of material inputs in production (e.g., embodied labor, energy, land, and water), rather than in terms of an underpayment of material inputs or an asymmetric transfer of 'value'". [27] In other words, uneven exchange is characterised by incommensurability, namely: the unequal transfer of material inputs; competing value-judgements of the worth of labor, fuel, and raw materials; differing availability of industrial technologies; and the off-loading of environmental burdens on those with less resources.[28] [29]
References
- ↑ In other words, capitalism is only attending to what society need, and by no means produce goods that are not necessary, neither acts in a destructive way whatsoever, as it only is concerned to provide 'utility' to real social necessity. Whether the aggregation of utility functions of individuals to utility functions of whole societies is possible, is disputed, because the active distortion of demand (such as techniques of merchandising) has no importance whatsoever, and what is deemed as 'consumerism' is just a fallacy, as there is no reason to believe we consume more than we need.
- ↑ Details are explained by microeconomics, for a text book see Henderson, Quandt 1971.
- ↑ Becker, Gary S. (1965). "A Theory of the Allocation of Time". The Economic Journal (Royal Economic Society) 75 (299): 493–517. doi:10.2307/2228949. ISSN 1468-0297. JSTOR 2228949 – via JSTOR. (registration required (help)).
- ↑ The conditions under which relative prices of commodities, if determined by marginal utilities, are proportional to amounts of labor necessary to produce these commodities, are discussed in L. Johansen: labor Theory of Value and Marginal Utilities. Economics of Planning 1963/3, p. 89-103.
- ↑ And whether the underlying mathematical functions are “well-behaved”, as the term is. Otherwise no optimum solution exists (and empirical data shows macro economy is an ideal field in perfect harmony and no conflicts).
- ↑ Capital, volume 1, chapter 8.
- ↑ Nikolai Bukharin, (1927) The Economic Theory of the Leisure Classes , ch. 4, part 3 .
- ↑ Capital, Volume 1, section 1
- ↑ Robert Nozick, Anarchy, State and Utopia
- ↑ Critique of the Gotha Program ch 1
- ↑ David Ramsay Steele, "From Marx to Mises: Post-Capitalist Society and the Challenge of Economic Calculation", La Salle: Open Court, 1992
- ↑ Karl Marx§ 3
- ↑ Self-description of Robert Paul Wolff
- ↑ Robert Paul Wolff, quoted in Ellerman's Property and Contract in Economics: the case for economic democracy ch 4
- ↑ Value, Price and Profit ch 6
- ↑ see ch1 of Capital
- ↑ See Marx's discussion of measures such length and the area of triangles in ch 20 p 312
- ↑ Freeman, Alan: Price, value and profit - a continuous, general treatment. In: Alan Freeman, Guglielmo Carchedi (editors): Marx and non-equilibrium economics. Edward Elgar. Cheltenham, UK, Brookfield, US 1996.
- ↑ For the difference between wage workers and working animals or slaves confer: John R. Bell: Capitalism and the Dialectic - The Uno-Sekine Approach to Marxian Political Economy, p. 45. London, Pluto Press 2009
- ↑ Albert Einstein: "Why Socialism?". Originally published 1949 in Monthly Review
- ↑ Karl Marx Capital, volume II, chapter XX. www.marxists.org
- ↑ Joan Robinson, "Economic Philosophy" p39
- ↑ Joan Robinson, "Economic Philosophy" p38
- ↑ Philip Pilkington, Marx, Hegel, The Labour Theory of Value and Human Desire
- ↑ Anson Rabinbach, "The human motor: Energy, fatigue, and the origins of modernity"
- ↑ Jean Baudrillard, "Pour une critique de l'économie politique du signe"
- ↑ Alf Hornborg, "Ecological economics, Marxism, and technological progress: Some explorations of the conceptual foundations of theories of ecologically unequal exchange."
- ↑ Alf Hornborg, "Ecological economics, Marxism, and technological progress: Some explorations of the conceptual foundations of theories of ecologically unequal exchange."
- ↑ Joan Martinez-Alier et al., "Weak comparability of values as a foundation for ecological economics."