Then there is another piece of foppery which is to be cautiously guarded against — the foppery of universality, — of knowing all sciences and excelling in all arts, — chemistry, mathematics, algebra, dancing, history, reasoning, riding, fencing, Low Dutch, High Dutch, natural philosophy, and enough Spanish to talk about Lope de Vega : in short, the modern precept of education very often is, "Take the Admirable Crichton for your model ; I would have you ignorant of nothing!" Now my advice, on the contrary, is, to have the courage to be ignorant of a great number of things, in order to avoid the calamity of being ignorant of every thing.
“I do not think altogether the worse of a book for having survived the author a generation or two. I have more confidence in the dead than the living.” — Hazlitt
8 February 2018
The Courage to Be Ignorant
Sydney Smith, "On the Conduct of the Understanding," Elementary Sketches of Moral Philosophy (London: Longman, Brown, Green, & Longmans, 1855), p. 99: