ABSTRACT
Economists, pursuing the rigor and respectability of “hard sciences,” are fond of observing that a good theory can be built on unrealistic or implausible assumptions, so long as it leads to realistic predictions or other useful results. This idea dates back at least to Milton Friedman (1953) in economics, and more importantly, draws on powerful, wellknown examples in physics. Nothing could be more intuitively implausible than quantum mechanics, yet its predictions have been confirmed in great detail.
