From our present point of view its only necessary application concerns the problems of a man's special occupation.

Every special performer needs the power of criticising the quality and the subject-matter of his own work.

Unless he has great gifts or happens to be brought up and trained under peculiarly propitious conditions, his first attempts to practice his art will necessarily be experimental.

He will be sure to commit many mistakes, not merely in the choice of alternative methods and the selection of his subject-matter, but in the extent to which he personally can approve or disapprove of his own achievements.

The thoroughly competent performer must at least possess the intellectual power of profiting from this experience.