It is now pretty generally recognized that the unities of time and space exclude from the sphere of painting story telling and history, which require for effective representation more than the single moment included in painting. In order to tell a story in painting, one has to supplement what is seen with ideas which can be obtained only from a catalogue or other source external to the picture; one has to add in thought to the moment given on the canvas the missing moments of the action. But a work of art should be complete in itself and so far as possible self-explanatory; it should not lead us away from itself, but keep us always to itself. If the scene represented be a part of a story, the story should be so well known that its connection with the picture can be immediately recognized without external aid, and should admit of a certain completeness in its various parts. The life of Christ is such a story; everybody knows it and can interpret a picture portraying it forthwith; its various incidents and situations have each a unique and complete significance in themselves. Historical paintings are not necessarily bad, of course, but the good ones are good despite the history, and a proof of their excellence consists in the fact that when we see them they make us forget for the moment our historical erudition. This norm does not exclude from the sphere of painting the expression of the relation of man to his fellows; it simply confines painting to the delineation of momentary and self-sufficient glimpses of social life. Pictures representing a mother and child, a pair of lovers, a family group, festival, tavern scene, or battle charge are illustrations. In Dutch painting the social life of Holland in the seventeenth century found its record; yet there is little or no anecdote. The genre, the representation of a group of people united by some common interest and with an appropriate background, has the same legitimacy, if not the same eminence, as the portrait. It does not possess the rank of the portrait because, since the interest is rather in the action or the situation portrayed, the figures are more merely typical, being developed only so far as is necessary to carry the action; seldom is a subtle and individualized inner life portrayed.