… is from pages 55-56 of the 2016 Mercatus Center re-issue of my late colleague Don Lavoie’s superb 1985 volume National Economic Planning: What Is Left? (footnote deleted; links added):
The intricate complexity of our economy is such that removing our profound ignorance of its detailed workings is not just an ambitious and difficult task, as [Wassily] Leontief avers; it is a hopeless dream. The fundamental defect of virtually all proposals for planning – from Marx to Leontief – lies in what Michael Polanyi calls their “objectivist,” or what F.A. Hayek calls their “rationalistic,” concept of their nature of human knowledge.