The Asymmetry of Sustainability and Their Consequences

The thesis of the paper is that sustainability is delimited by asymmetrical restrictions. At the one hand, a definition of sustainability must deal with crucial intergenerational issues of justice. On the other, it must confront the limitations of substitutability between natural capital and man-made capital, both in production and consumption. In the context of intergenerational justice, we are confronted with two fundamental problems: First, the policies of the present generation undoubtedly has consequences for the next generation, although the policies of future generations will have no consequences for the current one. Thus, we could ask: Why should we care about future generations? One possible answer is that we are connected by our children to the next generation and that the transition between ours and the next generation is not a sudden but continuous one. Normative answers have been put forward by Immanuel Kant in his categorical imperative and by John Rawls in his Theory of Justice. This analysis brings us the second problem: the ethical and economic basis of the concepts of strong and weak sustainability. The main difference between the two is the issue of substitutability between natural and man-made capital. The paper will show that in this area as well, we have to deal with asymmetric problems in the sense that if perfect substitutability were to be achieved in the production sector, it would not necessarily occur in the consumption sector, for example, when consumers do not accept new products (i.e. genetically-manipulated food)