… is from pages 89-90 of the 1964 Harper Torchbooks edition of Karl Popper’s deeply insightful 1957 book, The Poverty of Historicism (footnotes deleted):
The holistic planner overlooks the fact that it is easy to centralize power but impossible to centralize all the knowledge which is distributed over many individual minds, and whose centralization would be necessary for the wise wielding of centralized power. But this fact has far-reaching consequences. Unable to ascertain what is in the minds of so many individuals, he must try to simplify his problems by eliminating individual differences: he must try to control and stereotype interests and beliefs by education and propaganda.