The relation to Nature is particular since it appears impossible to avoid it: human beings are the product of their co-evolution with other living beings, irrespective of the progress in human autonomy, human life and survival remain dependent on ecosystem functioning. Some authors [29–31] explored the hypothesis that there is a critical level below which a decrease in ‘‘natural capital’’ could no longer be replaced by human activity, but instead resulted in a decrease in its effectiveness. If such a threshold exists, then, as suggested by D. Pearce [32], the economic analysis of biodiversity is relevant only insofar as this limit is not reached. When an option may lead to reach it, the question of substituting Nature or even nature’s
services raise issues on our scientific understanding of our biophysical dependence [33] and fundamental ethical issues [34].