"Don't degrade me into the position of giving you useful information. Education is an admirable thing, but it is well to remember from time to time that nothing that is worth knowing can be taught."
Oscar Wilde, "Intentions [#3]:  The critic as artist".
First published in 1890, reprinted in Richard Ellmann, ed., The Artist as Critic:
Critical writings of Oscar Wilde. New York: Random House, 1968, p. 349. 
Or, as the Chinese saying goes: