and decorated by figures of considerable delicacy and variety of form, so that we have no need here for painting. In the case of religious architecture, therefore, painting mainly appears in buildings which begin to approximate to the ancient type of architecture. As a rule, however, Christian painting is to be distinguished from the arts of building, and presents its works in independent form, as for example in large pictures, whether placed in chapels or on high altars. It is true that here, too, the picture must retain some relation to the character of the place, which it is destined to fill; for the rest, however, it is not merely intended to fill up wall spaces, but to hang them as a work of art independently just as a work of sculpture may do. In conclusion painting has its use as a decoration of halls and apartments in public buildings, town halls, palaces, and private houses, in which respect its association with architecture is once more closely marked, an association, however, in which its independence as a free art ought not to be lost. (_β_) A further necessary ground for the contraction of the spatial dimensions in painting to bare surface is due to the fact that the art of painting is concerned to express ideal conditions essentially in their separation[237], and thereby rich in every kind of particular character. A mere restriction to the shapes of _spatial_ form, with which sculpture is able to rest satisfied, vanishes therefore in the more luxuriant art; for the forms of spatial dimension are the most abstract in Nature, and an attempt must now be made to seize particular distinctions, in so far as the demand is now for an essentially more multifold material. The matter specifically defined in the _physical_ sense is attached to the very principle of presentation in Space, the differences of which[238], if they are to appear as essential in the work of art, themselves disclose this fact[239] in the total configuration of spatial form, which no longer remains the final mode of presentation, and they are compelled to make a breach in the complete form of spatial dimensions, in order to cancel the exclusive appearance of the physical medium. For the dimensions in painting are not presented by themselves in their actual reality, but are merely by means of this physical aspect made to appear and be visible as such. (_αα_) If we further inquire what is the nature of the _physical_ element which the art of painting makes use of we shall find this to be _Light_, regarding it as that medium which renders all objects whatever visible.