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.
In the art of calligraphy, people's vision is inspired by lines, so the lines of pen and ink have the reproducibility of understanding the objective world to some extent.
Extended data
The art of calligraphy is the art of lines. In calligraphers' works, some of these lines are as heavy as falling rocks, some as light as flying flowers, some as chiseling iron, some as agile as lightning, some as soft as buds, and each has its own merits.
In the final analysis, all the changes in the calligraphy of Hexi bamboo slips are the changes in the form and combination of lines, which have formed the characteristics of Hexi bamboo slips, so lines are the essence of China's calligraphy art.
Calligraphers use their works to reflect nature and society. The link between the artistic beauty of calligraphy and the beauty of heaven and earth, the beauty of mountains and rivers, and the social beauty of well-dressed figures is lines. In the art of calligraphy, calligraphers' rich emotions are also realized through lines, and the ever-changing lines in calligraphers' works are the expression of calligraphers' inner world.
China's calligraphy depicts a vivid picture of China's calligraphy history in the past ten thousand years through ever-changing lines.
Reference source: Baidu Encyclopedia-Calligraphy Aesthetics