The evolution of modern art has been still more injurious to æsthetic speculation than the progress of science. In the palmy days of art-philosophy conditions were eminently favourable to universal generalisations. The great periods of art, classical antiquity and the Renaissance, were so remote that only their simplest and most salient features were discerned. Nor did the art of the period exhibit the bewildering multiplicity of a fertile age,—least of all in Germany, the home and centre of æsthetic inquiry. The formative arts were less important than ever before; music, which was so soon to eclipse all other arts, had not yet awakened the interest of philosophers. The crafts were at a low ebb; landscape-gardening is indeed the only kind of applied art that we hear about at this time. Beauty, art, the ideal—these and all other general notions must have been suggested with unsurpassable simplicity by this uniform and monotonous artistic output. It is easy to understand the eagerness and the delight with which the earlier writers on æsthetic, once the impulse given, drew conclusions, made comparisons, and laid down laws. But it is equally evident that speculative zeal was bound to fall off as soon as the province of art was enlarged and its products differentiated. Even the more intimate knowledge of classical culture which was subsequently gained, necessitated important corrections in æsthetic dogmas. The artistic activities of savage tribes, which have been practically unknown to æsthetic writers until recent years, display many features that cannot be harmonised with the general laws. And in a yet higher degree contemporary art defies the generalisations of a uniform theory. With greater mastery over materials and technique, the different arts have been able to produce more and more specialised forms of beauty. The painter’s ideal can no longer be confused with that of the poet or the story-teller, nor the sculptor’s with that of the actor. Pure music, pure poetry, pure painting, thus develop into isolated, independent arts, of which each one establishes its own laws and conditions for itself. The critic who, in spite of this evolution, tries to apply a narrow æsthetic standard of beauty to all the various arts may indeed—according to his influence—delay the public appreciation of modern works, and thus indirectly impede artistic development. But no amount of theorising will enable him to arrest the growth of artistic forms whose very existence contradicts the generalisations of the old systems. And he is equally powerless to stop such violations of the supposed frontiers of the different arts as continually occur, for instance, in descriptive music, or in poetry like that of Gautier, which aims at producing a pictorial impression by means of words.