The goal of this paper is to point out that studying the metaphors used by specialists can yield useful information for a linguist eager to better understand the ideas that helped shape theory in a given field of knowledge. The metaphors suggested, adopted and discussed by economic cycle theorists in their own writings – in relation with the questions of equilibrium and crisis – illustrate the various roles metaphors can play at the heuristic, epistemological, and analytical levels, and in terms of model creation and argumentation. Starting with economic cycle terminology, which itself is metaphorical, the analysis shows how thinkers have borrowed from the two traditional metaphorical veins that have inspired economics: the economic cycle was first conceptualized thanks to metaphors inspired by the laws of nature, and then envisaged through the lens of physics. Intellectual and scientific exchanges between theorists are investigated to illustrate the various roles of metaphor and how metaphors have nourished their theoretical debates.