MULTIPLE MEANINGS OF RIGOUR AND PRECISION

At heart, the debate about economics imperialism might not have moved on very far from when Ralph Souter (1993b: 94) first introduced the notion into social science (see Chapter 1). This was in the 1930s. He argued that rigour and precision looked very different from beyond a mathematical mindset than from within it. They remain prized assets in economics imperialists’ rhetorical armoury but in the absence of Souter's reflections on the many meanings they might acquire. Explanation through mathematical analogy within the model will certainly bring additional rigour and precision to understandings of that world, but this should not be confused with saying that the world beyond the model is now fully understood. The system of equations will reveal mathematical solutions to what, in essence, are merely mathematical problems. Inductive inference to the world beyond the model involves a leap of faith that even the most aggressive selling of economics imperialism does nothing to overcome. The colonists purport to operate somewhere between the world within substitute models and actual day-to-day experiences, connecting the two in a causal explanation. Yet these are distinct ontological realms that respond to different standards of rigour and precision. Souter recognized this 90 years ago, but the long-forgotten nature of his work shows that his warnings went unheeded.

Souter (1933a: 377–8) had shown that the economists of his day were left with a choice of entering one of two strictly parallel domains: Lionel Robbins's new one or Alfred Marshall's old one. Robbins's is where economics imperialists continue to be positioned today, with rigour and precision being defined in relation to the logically sound specification of the world within the model. Marshall's attracts the critics of economics imperialism, because its definitions of rigour and precision are linked to how well the world within the model captures the characteristics of the empirical realities it is asked to imitate. In modern-day philosophical terms, two different representational relationships between model and target are being invoked: “standing for” the real world in the former, “making present” the real world in the latter, or representing versus re-presenting (Prendergast 2000: 5). Mathematical analogy can replace observational content in Robbins's model worlds and still be epistemically reasonable, but not in Marshall’s.