This evolution within the art-spirit has again in its own nature two sides. In the _first_ place the development itself is a spiritual[137] and universal one, in so far as the graduated series of definite _conceptions of the world_ as the definite but comprehensive consciousness of nature, man and God, gives itself artistic shape; and, in the _second_ place, this _universal_ development of art is obliged to provide itself with external existence and sensuous form, and the definite modes of the sensuous art-existence are themselves a totality of necessary distinctions in the realm of art--which are _the several arts_. It is true, indeed, that the necessary kinds of artistic representation are on the one hand _qua_ spiritual of a very general nature, and not restricted to any one material;[138] while sensuous existence contains manifold varieties of matter. But as this latter, like the mind, has the Idea potentially for its inner soul, it follows from this that particular sensuous materials have a close affinity and secret accord with the spiritual distinctions and types of art presentation. In its completeness, however, our science divides itself into three principal portions. _First_, we obtain a _general part_. It has for its content and object the universal Idea of artistic beauty--this beauty being conceived as the Ideal--together with the nearer relation of the latter both to nature and to subjective artistic production. _Secondly_, there develops itself out of the idea of artistic beauty a _particular_ part, in as far as the essential differences which this idea contains in itself evolve themselves into a scale _particular_ plastic[139] forms. In the _third_ place there results a _final_ part, which has for its subject the individualization of artistic beauty, that consists in the advance of art to the sensuous realization of its shapes and its self-completion as a system of the several arts[140] and their genera and species.