In this paper I reconstruct the birth, blossoming and decline of an eighteenth century program, namely “Moral Newtonianism”. I reconstruct the interaction, or co-existence, of different levels: positive theories, methodology, worldviews and trace the presence of scattered items of the various levels in the work of Hume, Adam Smith, Adam Ferguson, Dugald Stewart. I highlight how Mirowski’s reconstruction of the interaction between physics and economics may be extended to the eighteenth century in an interesting way once the outdated reconstruction of (...) Adam Smith that has been adopted by Mirowski is updated. I show how general methodological ideas, such as the distinction between ultimate causes or essences and intermediate principles, that originated in a context where the issue was the interaction between natural science and theology, proved useful when transferred to social theory in encouraging a kind of “experimental” approach to social phenomena. I discuss finally the genesis of frozen metaphors such as equilibrium, circulation, and value, arguing that Canguilhem’s lesson – namely that scientific change is produced not only by similarity but also by opposition – may be applied also to the history of economic thought. I take as an example Adam Smith’s ‘discovery’ of social mechanisms vis-à-vis his sceptical mistrust of neo-Stoic and Platonic views of a world-order. (shrink)