Talent can be made in twenty-four hours. Genius exists, but an ordinary man cannot be a genius. It is only a word. It is the same in all the arts. Real art cannot be the work of an ordinary man. He cannot act, he cannot be "I." An actor cannot have what another man has—he cannot feel as another man feels. If he plays the part of a priest, he ought to have the understanding and feelings of a priest. But he can have these only if he has all the priest's material, all that a priest knows and understands. And it is so with every profession; special knowledge is required. The artist without knowledge only imagines.
Views from the Real World p.177