Thank you for helping! I was wondering how I'd track that down through the lens on translation. I see I might still have to scramble, but this helps. And the Russel paraphrase is good confirmation.

Edit to add: Addresses to the German Nation (1807), Second Address : "The General Nature of the New Education". Chicago and London, The Open Court Publishing Company, 1922, p. 20.

There we go, OP delivers! Rejoice!

When quoting a person, a reference or source is necessary to be taken seriously. Especially by people who question just about everything