Not to keep from error, is the duty of the educator of men, but to guide the erring one, even to let him swill his error out of full cups — that is the wisdom of teachers. Whoever merely tastes of his error, will keep house with it for a long time, … but whoever drains it completely will have to get to know it.
Wilhelm Meister's Lehrjahre (Apprenticeship) (1786-1830)