"One of the marks of true genius is a quality of abundance. A rich, rollicking abundance, enough to give indigestion to ordinary people. Great artists turn it out in rolls, in swatches. They cover whole ceilings with paintings, they chip out a mountainside in stone, they write not one novel but a shelf full. It follows that some of their work is better than other. As much as a third of it may be pretty bad. Shall we say this unevenness is the mark of their humanity - of their proud mortality as well as of their immortality?"