Friedman held that important theories must rest on descriptively false assumptions

Evidence

To assess theories by whether their assumptions were empirically accurate was, Friedman argued, fundamentally mistaken: “Truly important and significant hypotheses will be found to have assumptions' that are wildly inaccurate descriptive representations of reality.... A hypothesis is important if it explains’ much by little … if it abstracts the common and crucial elements from the mass of complex and detailed circumstances … and permits valid predictions on the basis of them alone. To be important, therefore, a hypothesis must be descriptively false in its assumptions.” (p. 14) The test of a theory was not whether its assumptions were “descriptively `realistic,’ for they never are, but … whether the theory works, which means whether it yields sufficiently accurate predictions” (p. 15). — Donald MacKenzie, An Engine, Not a Camera, 54

Categorization

• DEFINE: Establishes the core methodological stance (Friedman’s instrumentalism/falsificationism) that the performativity thesis reacts against.
• XREF: Connects to the general ‘performativity vs. description’ framing of the book’s thesis, and to standard history-of-econ-thought treatments of Friedman’s methodology. — connects to: Friedman judged hypotheses solely by predictive capacity, not by realism of assumptions — Angus Burgin, The Great Persuasion: Reinventing Free…, 405; Modelers trained in the Friedman tradition ignored unrealistic assumptions and tested only implications. — Donald MacKenzie, An Engine, Not a Camera: How Financial…, 245; Friedman armed finance theorists against ‘unrealistic’ critiques of their models. — Donald MacKenzie, An Engine, Not a Camera: How Financial…, 62 (+2 more)

Broader Connections

• Friedman armed finance theorists against ‘unrealistic’ critiques of their models. #corroborates (0.92) — Donald MacKenzie, An Engine, Not a Camera, 62
• Frameworks for economic change should be judged by theoretical usefulness, not absolute truth. #corroborates (0.80) — Greta R. Krippner, The Financialization of the American…, 129
• Truth of a theory is independent of either its productivity or its non-application #complicates (0.78)