“Does what goes on inside show on the outside?” the 26-year-old Van Gogh wrote to his brother in his stirring letter about the struggle for artistic purpose and recognition. “Someone has a great fire in his soul and nobody ever comes to warm themselves at it, and passers-by see nothing but a little smoke at the top of the chimney.” It is a hollowing feeling every artist experiences at one point or another, this dispiriting mismatch between the ferocity of…