The paper focuses on the successive tensions that emerged in Geoffrey M. Hodgson’s thought in his passage from political economy to Darwinian social science. The main argument is that Hodgson’s tensions have their origins in two fundamental problems: the irrelevance of population thinking in analyzing both social structures and historical processes; and the necessity of different levels of abstraction in biology and social sciences. Hodgson resolves the first tension by shifting the focus of inquiry from the analysis of capitalism to the genesis of a single convention. But afterwards he is unable to come back down from the extremely abstract level of evolving systems (ranging from amoebas to humans) to the analysis of social problems in contemporary capitalism.