In the Principles of Economics (1890), Alfred Marshall wrote that "economics, like biology, deals with a matter, of which the inner nature and constitution, as well as the outer form, are constantly chnaging" (cited in Hodgson 1993). thus, economics "is a branch of biology broadly interpreted" (Ibid.) According to Marshall, "the Mecca of the economist lies in economic biology rather than in economic dynamics" (Hodgson, 1993). Although Marshall was clearly prone to the use of biological metaphors, his work remained primarily based on mechanical and physical analogies.

Throughout history, from Marshall's work onward, exchanges between economics and biology have been numerous and frequent. However, these relationships between the two disciplines have also been a great source of controversy. More speccifically, biological analogies and metaphors have often been considered as successive temptations of biological reductionism.

More recently, eminent scholars such as Geoffrey Hodgson and Thorbjorn Knudsen have advocated for a new approach based on waht they called "generalized Darwinism", which may help develop both alternative explanatory theories and new predictive models (Hodgson and Knudsen 2010). Once again, this call for the use of Darwinian principles in social science has somehow been received with cautiousness, many economists ans social scientists having reservations about the utility of a Darwinian framework to understand and explain the evolutionary mechanisms of social and economic systems.

In this paper, we consider that the key question is actually not whether generalized Darwinism can be useful or not. more precisely, we argue that the three core Drawinian principles of variation, selection and inheritance can, without any doubt, be fruitful in understanding both the fucntioning and the evolution of economic and social phenomena. However, what is more important are the charcateristics of these principles regarding human societies. In other words, we argue that what economists and other social scientists need to study and understand are the intrinsic features of both competition and selection in human economic systems. More fundamentally, we focus on both the scope and origins of what common language calls competition and "natural selection" in economics.

This article is organized as follows. The first section briefly presents the main historical exchanges between economics and biology which can be related to Darwinian evolutionary concepts. Section 2 then summarizes the Generalized Darwinism approach and the challenges attached to it. Section 3 is devoted to the study of the charcateristics of human and economic competitive and selective processes. We argue that these features cannot be considered, in almost any case, as being "natural". On the contrary, the framework that organizes the existence of competitive and selective pressures in human societies should be considered as "artificial", in the sense that it stems from ideological and political struggles. Finally, we advocate for a renewal of the exchanges between economics and biology, based on the use of tools and methods from the study of complex systems in biology and ecology, and which may help economists avoid new attempts of naturalization of economic phenomena.