The second requirement demands of the content of art that it shall be no abstraction. By this is not meant that it must be concrete, as the sensuous is alleged to be concrete in contrast to everything spiritual and intellectual. For everything that is genuinely true, in the realm of thought as well as in the domain of nature, is concrete, and has, in spite of universality, nevertheless, a particular and subjective character. By saying, for example, that God is simply One, the Supreme Being as such, we express thereby nothing but a lifeless abstraction of an understanding devoid of reason. Such a God, as indeed he is not conceived in his concrete truth, can furnish no content for art, least of all for plastic art. Thus the Jews and the Turks have not been able to represent their God, who is still more abstract, in the positive manner in which the Christians have represented theirs. For in Christianity God is conceived in his truth, and therefore concrete, as a person, as a subject, and, more precisely still, as Spirit. What he is as spirit appears to the religious consciousness as a Trinity of persons, which at the same time is One. Here the essence of God is the reconciled unity of universality and particularity, such unity alone being concrete. Hence, as a content in order to be true must be concrete in this sense, art demands the same concreteness; because a mere abstract idea, or an abstract universal, cannot manifest itself in a particular and sensuous unified form. If a true and therefore concrete content is to have its adequate sensuous form and shape, this sensuous form must--this being the third requirement--also be something individual, completely concrete, and one. The nature of concreteness belonging to both the content and the representation of art, is precisely the point in which both can coincide and correspond to each other. The natural shape of the human body, for example, is a sensuous concrete object, which is perfectly adequate to represent the spiritual in its concreteness; the view should therefore be abandoned that an existing object from the external world is accidentally chosen by art to express a spiritual idea. Art does not seize upon this or that form either because it simply finds it or because it can find no other, but the concrete spiritual content itself carries with it the element of external, real, yes, even sensuous, representation. And this is the reason why a sensuous concrete object, which bears the impress of an essentially spiritual content, addresses itself to the inner eye; the outward shape whereby the content is rendered visible and imaginable aims at an existence only in our heart and mind. For this reason alone are content and artistic shape harmoniously wrought. The mere sensuously concrete external nature as such has not this purpose for its only origin. The gay and variegated plumage of the birds shines unseen, and their song dies away unheard;