"Like the old ideal of God, the abstraction itself in its nakedness is never directly apprehensible to us. As in the case of God, we can know its manifestations only through works, which, while never completely revealing the total abstraction in the round, symbolize it by the manifestation of different faces of itself in works of art. Therefore, to feel beauty is to participate in the abstraction through a particular agency. In a sense, this is a reflection of the infiniteness of reality. For should we know the appearance of the abstraction itself, we would constantly reproduce only its image. As it is, we have the exhibition of the infinite variety of its inexhaustible facets, for which we should be grateful."
The Artist's reality - Philosophies of Art, Mark Rothko
E não, não acho que tudo possa ser considerado arte - excesso de relativismo leva ao esvaziamento do conceito; mas é um bom assunto para discutirmos um dia :)