Karl Popper's methodology highlights our scientific ignorance: hence the need to institutionalize open‐mindedness through controlled experiments that may falsify our fallible theories about the world. In his endorsement of “piecemeal social engineering,” Popper assumes that the social‐democratic state and its citizens are capable of detecting social problems, and of assessing the results of policies aimed at solving them, through a process of experimentation analogous to that of natural science. But we are not only scientifically but politically ignorant: ignorant of the (...) facts that underpin political debate, which are brought to our attention by theories that, as Max Weber emphasized, can be tested only through counterfactual thought experiments. Public‐opinion and political‐psychology research suggest that human beings are far too unaware, illogical, and doctrinaire to conduct the rigorous theorizing that would be necessary to make piecemeal social engineering work. F.A. Hayek realized that the public could not engage, specifically, in piecemeal economic regulation but failed to draw the conclusion that this was due to a specific type of political ignorance: ignorance of economic theory. (shrink)