This work deals with an unresolved question left open by Hayek: which are the circumstances that lead to prefer a formalized rule to a spontaneous one? This paper suggests that spontaneous and formal rules do not cancel out each other, but are the results of two distinct approaches on just one reality, which did not catch its dynamic indivisibility. It is true that a behavioural rule survives thanks to its efficiency, but it is not true that the autopoiesis of the norm is efficient per se.
Keywords: Social norms, evolutionary economics, Hayek
Jel Code: A12, D02, K10