It being lawful to paint then, is it lawful to paint everything? So long as the painting is confessed—yes; but if, even in the slightest degree, the sense of it be lost, and the thing painted be supposed real—no…. In the Camera di Correggio of San Lodovico at Parma, the trellises of vine shadow the walls, as if with an actual arbor; and the troops of children, peeping through the oval openings, luscious in color and faint in light, may well be expected every instant to break through, or hide behind the covert. The grace of their attitudes, and the evident greatness of the whole work, mark that it is painting, and barely redeem it from the charge of falsehood; but even so saved, it is utterly unworthy to take a place among noble or legitimate architectural decoration.
— Ruskin, The Seven Lamps of Architecture. Unique to Ruskin is the combination of an exceptionally acute aesthetic sense with an exceptionally acute moral sense, and this is one of the many moments when they struggle mightily against each other. Ruskin cannot help admiring the beauty of Correggio’s work here, but he is so deeply opposed to deception in art that he wishes he could reject it altogether.