Ever since the Crash of 2008 there has been a widespread recognition, both among economists and the general public, that economic theory has failed. But there is no consensus on the causes and the extent of that failure.
I believe that the failure is more profound than generally recognized. It goes back to the foundations of economic theory. Economics tried to model itself on Newtonian physics. It sought to establish universally and timelessly valid laws governing reality. But economics is a social science and there is a fundamental difference between the natural and social sciences. Social phenomena have thinking participants who base their decisions on imperfect knowledge. That is what economic theory has tried to ignore.
Scientific method needs an independent criterion, by which the truth or validity of its theories can be judged. Natural phenomena constitute such a criterion; social phenomena do not. That is because natural phenomena consist of facts that unfold independently of any statements that relate to them. The facts then serve as objective evidence by which the validity of scientific theories can be judged. That has enabled natural science to produce amazing results.
Social events, by contrast, have thinking participants who have a will of their own. They are not detached observers but engaged decision makers whose decisions greatly influence the course of events. Therefore the events do not constitute an independent criterion by which participants can decide whether their views are valid. In the absence of an independent criterion people have to base their decisions not on knowledge but on an inherently biased and to greater or lesser extent distorted interpretation of reality. Their lack of perfect knowledge or fallibility introduces an element of indeterminacy into the course of events that is absent when the events relate to the behavior of inanimate objects. The resulting uncertainty hinders the social sciences in producing laws similar to Newton’s physics.