He who knows not, and knows not that he knows not, is a fool. Shun him.
He who knows not, and knows that he knows not is simple. Teach him.
He who knows, and knows not that he knows, is asleep. Wake him.
He who knows, and knows that he knows is wise. Follow him.
Sir Richard Burton, Anonymous Arabic Proverb.
From the website Britannica:
Sir Richard Burton, in full Sir Richard Francis Burton, (born March 19, 1821, Torquay, Devonshire, England—died October 20, 1890, Trieste, Austria-Hungary [now in Italy]), English scholar-explorer and Orientalist who was the first European to discover Lake Tanganyika and to penetrate hitherto-forbidden Muslim cities. He published 43 volumes on his explorations and almost 30 volumes of translations, including an unexpurgated translation of The Arabian Nights.