Friedman saw himself as defending the legacy of the great British economist Alfred Marshall, for example against the accounts of "imperfect" or "monopolistic" competition put forward by E. H. Chamberlin and Joan Robinson (Friedman 1953a, pp. 38-39). The sentence that I have drawn on in this book's title invokes Marshall: "Marshall took the world as it is; he sought to construct an `engine' to analyze it, not a photographic reproduction of it."

Donald MacKenzie, An Engine, Not a Camera, loc. 1392