پیدا کردن زمینه های مشترک بین اقتصاد محیط زیست و اقتصاد پست کینزی

Post-Keynesian economics and ecological economics have in common that they are considered to be ‘heterodox’ schools of thought. Aside from that, there has not been a strong connection between them. Previous books on post-Keynesian economics contain no chapter on environmental or ecological issues. This neglect has led leading ecological economists to criticize post-Keynesians for succumbing to the same growth paradigm as the neoclassical school. This paper argues that the two approaches are complementary in the sense that they each have different strong points. Ecological economics has correctly pointed out that the growth of the global economy may not be welfare-improving anymore, whereas post-Keynesians have gained valuable insights into the functioning of the capitalist growth process. To determine the feasibility of a synthesis between the two schools, the paper compares their approaches to the problems of production, consumption, and economic dynamics as well as the associated policy recommendations. It shows that on a theoretical level the two schools have much in common, but their policy conclusions differ with regard to the desirability of further growth. The paper concludes that a synthesis of both approaches may lead to a better understanding of how a capitalist economy operates in a natural environment with limits to growth and to better-informed policy advice.

Post-Keynesian economics and ecological economics have in common that they are considered to be ‘heterodox’ schools of thought1. Aside from that, there has not been a strong connection between these two schools of thought. A New Guide to Post Keynesian Economics (Holt and Pressman, 2001) contains no chapter on ecological issues or environmental problems. This neglect has led ecological economists like Herman Daly (2007) to criticize post-Keynesians for succumbing to the same ‘growth mania’ as the neoclassical school. This paper argues that the two approaches are complementary in the sense that they each have different strong points. Ecological economists have correctly pointed out that the growth of the global economy may not be welfare-improving anymore, whereas post-Keynesians have gained valuable insights into the relationship between growth and important social issues such as unemployment and income distribution. Therefore, combining insights of both approaches may lead to a much better understanding of how a capitalist economy operates in a natural environment with limits to growth2. The starting point of many ecological economists is a normative question: “Do we want further growth?” They criticize neoclassical resource economics for ignoring the laws of nature, notably the principle of mass balance and the entropy law. According to the former, the mass of output must be equal to the mass of inputs, which implies that the production of material goods requires material inputs. Consequently, ecological economists reject the neoclassical aggregate production function, which allows generously for substitution between material and non-material inputs. The entropy law, as Georgescu-Roegen (1971) pointed out, implies that production is an irreversible process. This has led ecological economists to criticize the common neoclassical assumption of ‘malleable capital’ and recognise the importance of path dependence. Post-Keynesian economists, by contrast, ask a positive question: “How does growth come about in a capitalist economy?” Therefore, they are not necessarily growth enthusiasts. They agree with ecological economists in much of their criticism against the neoclassical mainstream. Their theory of consumer behaviour, as Lavoie (2005) shows, is in many ways similar. The same is true of their production theory (Christensen, 1989): Having rejected the neoclassical aggregate capital stock in the Capital Controversy, post-Keynesians generally view production as a transformation of inputs into outputs that is mostly characterised by fixed technology coefficients unless a capacity constraint is reached. The importance of dynamic concepts such as path dependence and the irreversibility of decisions, which is emphasised by ecological economists, was also realised by Joan Robinson (1980) and other post-Keynesians. The aim of this paper is to determine how the theoretical views of both schools can be reconciled and to show how this could contribute to providing actually relevant policy advice. To this end, the paper confronts the theoretical views held by post-Keynesian and ecological economists and the policy recommendations derived from those theories (Section 2), building on contributions of other authors who identified certain similarities in the fields of production theory (Christensen, 2005), consumption theory (Lavoie, 2005), and dynamic theory (Holt, 2005). Finally, conclusions are drawn and future research avenues are suggested in Section 3.

Eichner and Kregel (1975, p. 1294) believed that ‘post-Keynesian theory has the potential for becoming a comprehensive, positive alternative to the prevailing neoclassical paradigm’. More than 30 years later, however, neoclassical economics still dominates the mainstream of our science. Although Lavoie (2006b, p. xii) presents post-Keynesian theory as a ‘true alternative to the dominant school of economic thought’, it seems that most economists either find neoclassical theory more convincing than the post-Keynesian alternative or are unaware of the latter's existence. It is my impression that one of the reasons for this state of affairs lies in the failure of post-Keynesians to address environmental issues such as climate change and energy security. Many young economists are very much interested in these matters, and since the literature on these topics is almost exclusively written by neoclassical authors, they tend to follow in that tradition. The notable exception to this pattern arises in the field of ecological economics, whose founding fathers were very critical of the neoclassical theory of production. The literature that was reviewed in Section 2 of this paper shows that ecological economists have come to hold similar views as the post-Keynesians. However, communication between these two schools has been limited in the past. Combining insights from post-Keynesian economics and ecological economics could be beneficial for both schools. It would give post-Keynesian economics the practical relevance it needs, because environmental issues will continue to be on top of political and research agendas in the coming decades as the Earth gets warmer and natural resources get scarcer. Ecological economics would benefit from a proper macroeconomic framework with which to tackle the impact of environmental policy on other important issues such as income distribution, unemployment, and growth.