… is from page 217 of the 2015 Fourth Edition of Douglas Irwin’s superb book Free Trade Under Fire  (footnote deleted):
When several factors promoting a good outcome exist simultaneously – a stable political environment, a good educational system, high savings and literacy rates, and so on – it becomes difficult to determine the precise contribution of any one specific factor, such as industrial policy, to the outcome. One cannot rule out the possibility that government intervention actually detracted from the economic success of the country but was more than offset by the other good forces.
DBx: The complexity of society and the economy being as enormous as it is, one cannot hope to understand it by mere observation and measurement of ‘the facts.’ (The facts of the social sciences are themselves not only theoretical constructs, but ones that are unavoidably interpreted subjectively by the human minds that process them .) Attempting to understand the economy without a sound grasp of the economic way of thinking is as futile as trying to fly by flapping your arms. The only difference is that in the latter case the failure is immediately realized while in the former you can delude yourself and others into supposing that your attempt to understand reality merely through observation and careful measurement is a success.