"If in individual possesses a pictorial sense, whatever he creates guided by this sense will always lie within the domain of painting. Wood, paper, cloth, leather, glass, string, oil cloth, majolica, tin and all metals, colors, blue etc. etc will enter as most legitimate materials in our present artistic constructions.
The quantity and selection of this material will be regulated case by case by our creative spirit, which in matters of art, is the only authoritative arbiter that we admit.
Thus if all categories become modified and destroyed, categories which were completely arbitrary in any case, and which made of art an artificial game perpetrated with colors and canvas, for art this will be an advantage, for it will be liberated from every prejudice and will manifest itself in its greatest sincerity and purity."
—from IN Defiance of Painting, Cubism, Futurism and the Invention of Collage