Symbol, in the signification we here attach to the word, is not merely the beginning of art from the point of view of its notional development, but marks also its first appearance in history. We may consequently regard it as only the forecourt of art, which is principally the possession of the East, and through which, after a variety of transitional steps and mediating passages, we are at last introduced to the genuine realization of the Ideal in the classical type of art. We must therefore from the very first take care to distinguish symbol where its unique characteristics provide it with an independent sphere of its own, in which it determines the radical and effective type of a certain form of art's exposition and presentment from that kind of symbolic expression which amounts to no more than a purely external aspect of form entirely without such independent significance. In the latter sense we, in fact, come across it in the classical and romantic forms of art just as certain aspects of symbolical art are not wholly without the characteristic features of the classical Ideal, or present to us the origins of romantic art. Such reciprocal interplay between the fundamental forms of art attaches, however, merely to subsidiary images or isolated traits; it has no power whatever to modify, still less to expunge, the animating principle which essentially determines the character of the entire work of art. In such cases where we find symbol elaborated in its entirely unique and independent form it is as a general rule characterized by the quality of the _sublime_, because its main impression is to show us the Idea still united to measureless dimension rather than rounded in a free and self-defined content; it would fain clothe itself with form, and yet is unable to secure in the substantial appearances of the world a definite form which is entirely adequate to express the abstractness and universality of its longing. On account of this inability to attain its purpose the Idea passes over and beyond the external existence which surrounds it instead of penetrating to the core or completely making its home therein. And this flight beyond the limits of the finite and visible world is precisely that which constitutes the general character of the sublime. But before we proceed further it will be convenient, by way of elucidating the formal aspect of our subject, to explain at once, if in quite general terms, what we understand by the expression symbol.