Read the following excerpt from Robert Louis Stevenson's Essay in the Art of Writing and answer the question: There is nothing more disenchanting to man than to be shown the springs and mechanism of any art. All our arts and occupations lie wholly on the surface; it is on the surface that we perceive their beauty, fitness, and significance; and to pry below is to be appalled by their emptiness and shocked by the coarseness of the strings and pulleys. In a similar way, psychology itself, when pushed to any nicety, discovers an abhorrent baldness, but rather from the fault of our analysis than from any poverty native to the mind. And perhaps in aesthetics the reason is the same: those disclosures which seem fatal to the dignity of art seem so perhaps only in the proportion of our ignorance; and those conscious and unconscious artifices which it seems unworthy of the serious artist to employ were yet, if we had the power to trace them to their springs, indications of a delicacy of the sense finer than we conceive, and hints of ancient harmonies in nature. […] I must therefore warn that well-known character, the general reader, that I am here embarked upon a most distasteful business: taking down the picture from the wall and looking on the back; and, like the inquiring child, pulling the musical cart to pieces.

How does the line in bold use diction to create meaning?

The author refers to "that well-known character," meaning the main protagonists of most literary works that have come to be considered classics. This description reminds the reader that many characters are universal.
The author refers to "the general reader," who is the kind of person who loves tearing things apart to learn what they are made of. This process, Stevenson writes, allows readers to understand the beauty of literature.
The author writes about "pulling the musical cart to pieces," which describes the literary analysis process as similar to taking apart a musical instrument. Once the process is complete, the beauty is gone.
The author writes "that I am here embarked upon" the process of literary analysis, which he explains is an important journey for all writers to take because it will improve their ability to communicate clearly.