Calligraphy art is based on emotional expression, not cognitive reproduction. That is to say, as the materialized form of calligraphy art, lines are "from the inside out, with the heart and hands" (Chao Shuo's Calligraphy Examination), which is the expression of the calligrapher's subjective world, rather than the reproduction of the objective world. Calligraphy art should belong to the category of expressive art. In calligraphy art, people's vision is inspired by lines, so the lines of pen and ink have the reproducibility of understanding the objective world to a certain extent. This is what Yong said in On Pen: "For the body of a book, it must be in its shape" and "Only when there are vertical and horizontal images can a book be called." This constitutes the dual characteristics of the beauty of calligraphy, which has relative reproducibility in the form of expression.
The brushwork lines and structure of calligraphy can't reproduce an object in the objective world, but it is an "image" rather than a "concrete" that symbolizes an object in the objective world in a subjective form. Therefore, the richer and more vivid the expression in calligraphy aesthetics, the more abundant and diverse its reproducibility. It can be seen that the duality of calligraphy beauty is based on performance, supplemented by reproduction, and complement each other.