One of the principal signs of the decay of art is the mixture of its various kinds.  The arts themselves, as well as their branches, are related to one another, and have a certain tendency to unite, even to lose themselves in one another; but it is in this that the duty, the merit, the dignity of the real artist consists, namely, in being able to separate the field of art in which he works from others, in placing every art and every branch of art on its own footing, and in isolating it as far as possible.

It has been noticed that all plastic art strives toward painting, all literary art toward the drama, and this observation may in the future give us occasion for important reflections.

The genuine law-giving artist strives for the truth of art, the lawless artist who follows a blind impulse strives for the reality of Nature; through the former, art reaches its highest summit, through the latter its lowest stage.

What holds good of art in general holds good also of the kinds of art.  The sculptor must think and feel differently from the painter, indeed he must proceed when he wishes to produce a work in relief, in a different fashion from that which he will employ for a work in the round.  By the raising of low reliefs higher and higher, by the making of various parts and figures stand out completely, and finally by the adding of buildings and landscapes, so that work was produced which was half painting and half puppet-show, true art steadily declined.  Excellent artists of modern times have unfortunately pursued this course.

When in the future we express such maxims as we think sound, we should like, since they are deduced from works of art, to have them put to the test of practice by the artist.  How rarely one can come to a theoretical agreement with anyone else on a fundamental principle.  That which is applicable and useful, on the other hand, is decided upon much more quickly.  How often we see artists in embarrassment over the choice of subjects, over the general type of composition adapted to their art, and the detailed arrangement; how often the painter over the choice of colors!  Then is the time to test a principle, then will it he easier to decide whether it is bringing us closer to the great models and to everything that we value and love in them, or whether it leaves us entangled in the empirical confusion of an experience that has not been sufficiently thought out.

If such maxims hold good in training:  the artist, in guiding him in many an embarrassment, they will serve also in the development, valuation, and judgment of old and new works of art, and will in turn arise from an observation of these works.  Indeed, it is all the more necessary to adhere to this, because, notwithstanding the universally praised excellences of antiquity, individuals and whole nations among the moderns often fail to recognize wherein lies the highest excellence of those works.

An exact test will protect us best from this evil.  For that reason let us cite only one example to show what usually happens to the amateur in plastic art, so that we may make clear how necessary it is that criticism of ancient as well as modern works should be exact if it is to be of any use.