It's simple to say, but very difficult to bring off, something that cannot be taught and really is hard to pin down, and it either works or it doesn't.

NPR: Conductor James DePreist

Drawing on Warren Buffett's observation that it cannot be a coincidence that a group of investors taught by Benjamin Graham can make above average returns, Mr Mallaby presents original research on the performance of a group of fund managers who worked with Julian Robertson at Tiger Management, and similarly reveals superior returns.

ECONOMIST: Learning and learning

Although Socrates and his interlocutor probed whether virtue could be taught, the conclusion reached, in the last paragraph, is that it cannot, since all efforts at defining it failed, and that it was instead a divine gift.

ECONOMIST: Letters